System, method, and article of manufacture for a reconfigurable hardware-based audio decoder

Abstract

A system, method and article of manufacture are provided for decoding compressed audio data. A bitstream is read utilizing reconfigurable hardware, where the bitstream includes compressed audio data. The data in the bitstream is interpreted, and then decoded utilizing reconfigurable hardware. The decoded data is quantized. Stereo signals of the decoded data are decoded. The decoded data is processed for output.

Description

FIELD OF THE INVENTION

[0002] The present invention relates to multimedia devices and more particularly to a flexible multimedia hardware device that can encode/decode MPEG 1 Layer III (MP3) formatted audio data.

BACKGROUND OF THE INVENTION

[0003] It is well known that software-controlled machines provide great flexibility in that they can be adapted to many different desired purposes by the use of suitable software. As well as being used in the familiar general purpose computers, software-controlled processors are now used in many products such as cars, telephones and other domestic products, where they are known as embedded systems.

[0004] However, for a given a function, a software-controlled processor is usually slower than hardware dedicated to that function. A way of overcoming this problem is to use a special software-controlled processor such as a RISC processor which can be made to function more quickly for limited purposes by having its parameters (for instance size, instruction set etc.) tailored to the desired functionality.

[0005] Where hardware is used, though, although it increases the speed of operation, it lacks flexibility and, for instance, although it may be suitable for the task for which it was designed it may not be suitable for a modified version of that task which is desired later. It is now possible to form the hardware on reconfigurable logic circuits, such as Field Programmable Gate Arrays (FPGA's) which are logic circuits which can be repeatedly reconfigured in different ways. Thus they provide the speed advantages of dedicated hardware, with some degree of flexibility for later updating or multiple functionality.

[0006] In general, though, it can be seen that designers face a problem in finding the right balance between speed and generality. They can build versatile chips which will be software controlled and thus perform many different functions relatively slowly, or they can devise application-specific chips that do only a limited set of tasks but do them much more quickly.

[0007] A compromise solution to these problems can be found in systems which combine both dedicated hardware and also software. The hardware is dedicated to particular functions, e.g. those requiring speed, and the software can perform the remaining functions. The design of such systems is known as hardware-software codesign.

[0008] Within the design process, the designer must decide, for a target system with a desired functionality, which functions are to be performed in hardware and which in software. This is known as partitioning the design. Although such systems can be highly effective, the designer must be familiar with both software and hardware design. It would be advantageous if such systems could be designed by people who have familiarity only with software and which could utilize the flexibility of configurable logic resources. Further, it would be advantageous to implement into such systems an intuitive, ergonomic interface for selecting and controlling functions.

[0009] It would also be advantageous to provide a tool for encoding and decoding of audio data in the MPEG 1 Layer III (MP3) compression format. MP3 compression is the third and most advanced of the audio compression formats available for MPEG encoded multimedia data.

[0010] MP3 is a lossy compression format, based on the acoustic properties of the human ear. In brief, it transforms an input audio signal into the frequency domain and then using a number of properties of human hearing, it is able to discard a significant proportion of data without a listener perceiving any change thus massively reducing storage space. Typical compression ratios for MP3 are 8-10 times that of the original raw sample data, making it a perfect format for distribution of music over the Internet.

SUMMARY OF THE INVENTION

[0011] A system, method and article of manufacture are provided for decoding compressed audio data, such as audio data compressed in MPEG 1 Layer III (MP3) format. A bitstream is read utilizing reconfigurable hardware, where the bitstream includes compressed audio data. The data in the bitstream is interpreted, and then decoded utilizing reconfigurable hardware. Note that the decoding hardware can be a portion of the hardware that reads the bitstream, or can be an entirely separate piece of hardware that is in communication with the reading hardware. The decoded data is quantized. Stereo signals of the decoded data are decoded. The decoded data is processed for output. Note that the present invention would work equally well with other forms of audio and video encoding/compression.

[0012] In one aspect of the present invention, the reconfigurable hardware includes one or more Field Programmable Gate Arrays (FPGAs). In another aspect of the present invention, a processor is emulated in reconfigurable logic. The processor interprets the data in the bitstream and dequantizes the decoded data in software. The processor can also be used to control the reconfigurable hardware.

[0013] In an aspect of the present invention, the processing of the decoded data for output includes transforming the decoded data into an intermediate form utilizing Inverse Modified Discrete Cosine Transform (IMDCT) filters, and transforming the data in the intermediate form to a final form utilizing polyphase filters.

[0014] In a preferred embodiment, several of the operations are performed in parallel in a pipeline. This makes the decoding very fast. Ideally, a locking system manages access to resources during performance of the operations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be better understood when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

[0016] FIG. 1 is a schematic diagram of a hardware implementation of one embodiment of the present invention;

[0017] FIG. 2 is a flow diagram of a process for providing an interface for transferring configuration data to a reconfigurable logic device;

[0018] FIG. 3 depicts a display according to an exemplary embodiment of the present invention;

[0019] FIG. 4 illustrates an illustrative procedure for initiating a reconfigurable logic device according to the illustrative embodiment of FIG. 3;

[0020] FIG. 5 depicts a process for using a reconfigurable logic device to place a call over the Internet according to the illustrative embodiment of FIG. 3;

[0021] FIG. 6 illustrates a process for answering a call over the Internet;

[0022] FIG. 7 depicts a configuration screen for setting various parameters of telephony functions according to the illustrative embodiment of FIG. 3;

[0023] FIG. 8A depicts an illustrative screen displayed upon receonfiguration of a reconfigurable logic device according to the illustrative embodiment of FIG. 3;

[0024] FIG. 8B depicts a process for providing a user interface for a decoder of audio data in the MPEG 1 Layer III (MP3) format;

[0025] FIG. 8C illustrates a process for decoding compressed audio data according to an embodiment of the present invention;

[0026] FIG. 8D illustrates the discrete modules and data flow in an MP3 decoder according to a preferred embodiment of the present invention;

[0027] FIG. 8E shows sample code for the implementation of the memory-mapped hardware control;

[0028] FIG. 9A depicts a process for providing a hardware-based reconfigurable multimedia device;

[0029] FIG. 9B is a diagrammatic overview of a board of the resource management device according to an illustrative embodiment of the present invention;

[0030] FIG. 10 depicts a JTAG chain for the board of FIG. 9;

[0031] FIG. 11 shows a structure of a Parallel Port Data Transmission System according to an embodiment of the present invention;

[0032] FIG. 12 is a flowchart that shows the typical series of procedure calls when receiving data;

[0033] FIG. 13 is a flow diagram depicting the typical series of procedure calls when transmitting data;

[0034] FIG. 14 is a flow diagram illustrating several processes running in parallel;

[0035] FIG. 15 is a block diagram of an FPGA device according to an exemplary embodiment of the present invention;

[0036] FIG. 16 is a flowchart of a process for network-based configuration of a programmable logic device;

[0037] FIG. 17 illustrates a process for remote altering of a configuration of a hardware device; and

[0038] FIG. 18 illustrates a process for processing data and controlling peripheral hardware.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] A preferred embodiment of a system in accordance with the present invention is preferably practiced in the context of a personal computer such as an IBM compatible personal computer, Apple Macintosh computer or UNIX based workstation. A representative hardware environment is depicted in FIG. 1, which illustrates a typical hardware configuration of a workstation in accordance with a preferred embodiment having a central processing unit 110, such as a microprocessor, and a number of other units interconnected via a system bus 112. The workstation shown in FIG. 1 includes a Random Access Memory (RAM) 114, Read Only Memory (ROM) 116, an I/O adapter 118 for connecting peripheral devices such as disk storage units 120 to the bus 112, a user interface adapter 122 for connecting a keyboard 124, a mouse 126, a speaker 128, a microphone 132, and/or other user interface devices such as a touch screen (not shown) to the bus 112, communication adapter 134 for connecting the workstation to a communication network (e.g., a data processing network) and a display adapter 136 for connecting the bus 112 to a display device 138. The workstation also includes a Field Programmable Gate Array (FPGA) 140 with a complete or a portion of an operating system thereon such as the Microsoft Windows NT or Windows/98 Operating System (OS), the IBM OS/2 operating system, the MAC OS, or UNIX operating system. Those skilled in the art will appreciate that the present invention may also be implemented on platforms and operating systems other than those mentioned.

[0040] The graphics processor 136 set forth in FIG. 1 includes a graphics processing system which offloads graphics processing from the central processing unit 110. In one embodiment of the present invention, the graphics acceleration integrated circuit may include, at least in part, a field programmable gate array (FPGA) device. Use of such device provides flexibility in functionality, while maintaining high processing speeds.

[0041] Examples of such FPGA devices include the XC2000™ and XC3000™ families of FPGA devices introduced by Xilinx, Inc. of San Jose, Calif. The architectures of these devices are exemplified in U.S. Pat. Nos. 4,642,487; 4,706,216; 4,713,557; and 4,758,985; each of which is originally assigned to Xilinx, Inc. and which are herein incorporated by reference for all purposes. It should be noted, however, that FPGA's of any type may be employed in the context of the present invention.

[0042] An FPGA device can be characterized as an integrated circuit that has four major features as follows.

[0043] (1) A user-accessible, configuration-defining memory means, such as SRAM, PROM, EPROM, EEPROM, anti-fused, fused, or other, is provided in the FPGA device so as to be at least once-programmable by device users for defining user-provided configuration instructions. Static Random Access Memory or SRAM is of course, a form of reprogrammable memory that can be differently programmed many times. Electrically Erasable and reProgrammable ROM or EEPROM is an example of nonvolatile reprogrammable memory. The configuration-defining memory of an FPGA device can be formed of mixture of different kinds of memory elements if desired (e.g., SRAM and EEPROM) although this is not a popular approach.

[0044] (2) Input/Output Blocks (IOB's) are provided for interconnecting other internal circuit components of the FPGA device with external circuitry. The IOB's' may have fixed configurations or they may be configurable in accordance with user-provided configuration instructions stored in the configuration-defining memory means.

[0045] (3) Configurable Logic Blocks (CLB's) are provided for carrying out user-programmed logic functions as defined by user-provided configuration instructions stored in the configuration-defining memory means.

[0046] Typically, each of the many CLB's of an FPGA has at least one lookup table (LUT) that is user-configurable to define any desired truth table,—to the extent allowed by the address space of the LUT. Each CLB may have other resources such as LUT input signal pre-processing resources and LUT output signal post-processing resources. Although the term ‘CLB’ was adopted by early pioneers of FPGA technology, it is not uncommon to see other names being given to the repeated portion of the FPGA that carries out user-programmed logic functions. The term, ‘LAB’ is used for example in U.S. Pat. No. 5,260,611 to refer to a repeated unit having a 4-input LUT.

[0047] (4) An interconnect network is provided for carrying signal traffic within the FPGA device between various CLB's and/or between various IOB's and/or between various IOB's and CLB's. At least part of the interconnect network is typically configurable so as to allow for programmably-defined routing of signals between various CLB's and/or IOB's in accordance with user-defined routing instructions stored in the configuration-defining memory means.

[0048] In some instances, FPGA devices may additionally include embedded volatile memory for serving as scratchpad memory for the CLB's or as FIFO or LIFO circuitry. The embedded volatile memory may be fairly sizable and can have 1 million or more storage bits in addition to the storage bits of the device's configuration memory.

[0049] Modern FPGA's tend to be fairly complex. They typically offer a large spectrum of user-configurable options with respect to how each of many CLB's should be configured, how each of many interconnect resources should be configured, and/or how each of many IOB's should be configured. This means that there can be thousands or millions of configurable bits that may need to be individually set or cleared during configuration of each FPGA device.

[0050] Rather than determining with pencil and paper how each of the configurable resources of an FPGA device should be programmed, it is common practice to employ a computer and appropriate FPGA-configuring software to automatically generate the configuration instruction signals that will be supplied to, and that will ultimately cause an unprogrammed FPGA to implement a specific design. (The configuration instruction signals may also define an initial state for the implemented design, that is, initial set and reset states for embedded flip flops and/or embedded scratchpad memory cells.)

[0051] The number of logic bits that are used for defining the configuration instructions of a given FPGA device tends to be fairly large (e.g., 1 Megabits or more) and usually grows with the size and complexity of the target FPGA. Time spent in loading configuration instructions and verifying that the instructions have been correctly loaded can become significant, particularly when such loading is carried out in the field.

[0052] For many reasons, it is often desirable to have in-system reprogramming capabilities so that reconfiguration of FPGA's can be carried out in the field.

[0053] FPGA devices that have configuration memories of the reprogrammable kind are, at least in theory, ‘in-system programmable’ (ISP). This means no more than that a possibility exists for changing the configuration instructions within the FPGA device while the FPGA device is ‘in-system’ because the configuration memory is inherently reprogrammable. The term, ‘in-system’ as used herein indicates that the FPGA device remains connected to an application-specific printed circuit board or to another form of end-use system during reprogramming. The end-use system is of course, one which contains the FPGA device and for which the FPGA device is to be at least once configured to operate within in accordance with predefined, end-use or ‘in the field’ application specifications.

[0054] The possibility of reconfiguring such inherently reprogrammable FPGA's does not mean that configuration changes can always be made with any end-use system. Nor does it mean that, where in-system reprogramming is possible, that reconfiguration of the FPGA can be made in timely fashion or convenient fashion from the perspective of the end-use system or its users. (Users of the end-use system can be located either locally or remotely relative to the end-use system.)

[0055] Although there may be many instances in which it is desirable to alter a pre-existing configuration of an ‘in the field’ FPGA (with the alteration commands coming either from a remote site or from the local site of the FPGA), there are certain practical considerations that may make such in-system reprogrammability of FPGA's more difficult than first apparent (that is, when conventional techniques for FPGA reconfiguration are followed).

[0056] A popular class of FPGA integrated circuits (IC's) relies on volatile memory technologies such as SRAM (static random access memory) for implementing on-chip configuration memory cells. The popularity of such volatile memory technologies is owed primarily to the inherent reprogrammability of the memory over a device lifetime that can include an essentially unlimited number of reprogramming cycles.

[0057] There is a price to be paid for these advantageous features, however. The price is the inherent volatility of the configuration data as stored in the FPGA device. Each time power to the FPGA device is shut off, the volatile configuration memory cells lose their configuration data. Other events may also cause corruption or loss of data from volatile memory cells within the FPGA device.

[0058] Some form of configuration restoration means is needed to restore the lost data when power is shut off and then re-applied to the FPGA or when another like event calls for configuration restoration (e.g., corruption of state data within scratchpad memory).

[0059] The configuration restoration means can take many forms. If the FPGA device resides in a relatively large system that has a magnetic or optical or opto-magnetic form of nonvolatile memory (e.g., a hard magnetic disk)--and the latency of powering up such a optical/magnetic device and/or of loading configuration instructions from such an optical/magnetic form of nonvolatile memory can be tolerated—then the optical/magnetic memory device can be used as a nonvolatile configuration restoration means that redundantly stores the configuration data and is used to reload the same into the system's FPGA device(s) during power-up operations (and/or other restoration cycles).

[0060] On the other hand, if the FPGA device(s) resides in a relatively small system that does not have such optical/magnetic devices, and/or if the latency of loading configuration memory data from such an optical/magnetic device is not tolerable, then a smaller and/or faster configuration restoration means may be called for.

[0061] Many end-use systems such as cable-TV set tops, satellite receiver boxes, and communications switching boxes are constrained by prespecified design limitations on physical size and/or power-up timing and/or security provisions and/or other provisions such that they cannot rely on magnetic or optical technologies (or on network/satellite downloads) for performing configuration restoration. Their designs instead call for a relatively small and fast acting, non-volatile memory device (such as a securely-packaged EPROM IC), for performing the configuration restoration function. The small/fast device is expected to satisfy application-specific criteria such as: (1) being securely retained within the end-use system; (2) being able to store FPGA configuration data during prolonged power outage periods; and (3) being able to quickly and automatically re-load the configuration instructions back into the volatile configuration memory (SRAM) of the FPGA device each time power is turned back on or another event calls for configuration restoration.

[0062] The term ‘CROP device’ will be used herein to refer in a general way to this form of compact, nonvolatile, and fast-acting device that performs ‘Configuration-Restoring On Power-up’ services for an associated FPGA device.

[0063] Unlike its supported, volatilely reprogrammable FPGA device, the corresponding CROP device is not volatile, and it is generally not ‘in-system programmable’. Instead, the CROP device is generally of a completely nonprogrammable type such as exemplified by mask-programmed ROM IC's or by once-only programmable, fuse-based PROM IC's. Examples of such CROP devices include a product family that the Xilinx company provides under the designation ‘Serial Configuration PROMs’ and under the trade name, XC1700D.™. These serial CROP devices employ one-time programmable PROM (Programmable Read Only Memory) cells for storing configuration instructions in nonvolatile fashion.

[0064] A preferred embodiment is written using Handel-C. Handel-C is a programming language marketed by Celoxica Limited, 7-8 Milton Park, Abingdon, Oxfordshire, OX14 4RT, United Kingdom. Handel-C is a programming language that enables a software or hardware engineer to target directly FPGAs (Field Programmable Gate Arrays) in a similar fashion to classical microprocessor cross-compiler development tools, without recourse to a Hardware Description Language. Thereby allowing the designer to directly realize the raw real-time computing capability of the FPGA.

[0065] Handel-C is designed to enable the compilation of programs into synchronous hardware; it is aimed at compiling high level algorithms directly into gate level hardware.

[0066] The Handel-C syntax is based on that of conventional C so programmers familiar with conventional C will recognize almost all the constructs in the Handel-C language.

[0067] Sequential programs can be written in Handel-C just as in conventional C but to gain the most benefit in performance from the target hardware its inherent parallelism must be exploited.

[0068] Handel-C includes parallel constructs that provide the means for the programmer to exploit this benefit in his applications. The compiler compiles and optimizes Handel-C source code into a file suitable for simulation or a net list which can be placed and routed on a real FPGA.

[0069] More information regarding the Handel-C programming language may be found in “EMBEDDED SOLUTIONS Handel-C Language Reference Manual: Version 3,” “EMBEDDED SOLUTIONS Handel-C User Manual: Version 3.0,” “EMBEDDED SOLUTIONS Handel-C Interfacing to other language code blocks: Version 3.0,” each authored by Rachel Ganz, and published by Celoxica Limited in the year of 2001; and “EMBEDDED SOLUTIONS Handel-C Preprocessor Reference Manual: Version 2. 1,” also authored by Rachel Ganz and published by Embedded Solutions Limited in the year of 2000; and which are each incorporated herein by reference in their entirety. Also, United States Patent Application entitled SYSTEM, METHOD AND ARTICLE OF MANUFACTURE FOR INTERFACE CONSTRUCTS IN A PROGRAMMING LANGUAGE CAPABLE OF PROGRAMMING HARDWARE ARCHITECTURES and assigned to common assignee Celoxica Limited provides more detail about programming hardware using Handel-C and is herein incorporated by reference in its entirety for all purposes.

[0070] It should be noted that other programming and hardware description languages can be utilized as well, such as VHDL.

[0071] Another embodiment of the present invention may be written at least in part using JAVA, C, and the C++ language and utilize object oriented programming methodology. Object oriented programming (OOP) has become increasingly used to develop complex applications. As OOP moves toward the mainstream of software design and development, various software solutions require adaptation to make use of the benefits of OOP. A need exists for these principles of OOP to be applied to a messaging interface of an electronic messaging system such that a set of OOP classes and objects for the messaging interface can be provided.

[0072] OOP is a process of developing computer software using objects, including the steps of analyzing the problem, designing the system, and constructing the program. An object is a software package that contains both data and a collection of related structures and procedures. Since it contains both data and a collection of structures and procedures, it can be visualized as a self-sufficient component that does not require other additional structures, procedures or data to perform its specific task. OOP, therefore, views a computer program as a collection of largely autonomous components, called objects, each of which is responsible for a specific task. This concept of packaging data, structures, and procedures together in one component or module is called encapsulation.

[0073] In general, OOP components are reusable software modules which present an interface that conforms to an object model and which are accessed at run-time through a component integration architecture. A component integration architecture is a set of architecture mechanisms which allow software modules in different process spaces to utilize each others capabilities or functions. This is generally done by assuming a common component object model on which to build the architecture. It is worthwhile to differentiate between an object and a class of objects at this point. An object is a single instance of the class of objects, which is often just called a class. A class of objects can be viewed as a blueprint, from which many objects can be formed.

[0074] OOP allows the programmer to create an object that is a part of another object. For example, the object representing a piston engine is said to have a composition-relationship with the object representing a piston. In reality, a piston engine comprises a piston, valves and many other components; the fact that a piston is an element of a piston engine can be logically and semantically represented in OOP by two objects.

[0075] OOP also allows creation of an object that “depends from” another object. If there are two objects, one representing a piston engine and the other representing a piston engine wherein the piston is made of ceramic, then the relationship between the two objects is not that of composition. A ceramic piston engine does not make up a piston engine. Rather it is merely one kind of piston engine that has one more limitation than the piston engine; its piston is made of ceramic. In this case, the object representing the ceramic piston engine is called a derived object, and it inherits all of the aspects of the object representing the piston engine and adds further limitation or detail to it. The object representing the ceramic piston engine “depends from” the object representing the piston engine. The relationship between these objects is called inheritance.

[0076] When the object or class representing the ceramic piston engine inherits all of the aspects of the objects representing the piston engine, it inherits the thermal characteristics of a standard piston defined in the piston engine class. However, the ceramic piston engine object overrides these ceramic specific thermal characteristics, which are typically different from those associated with a metal piston. It skips over the original and uses new functions related to ceramic pistons. Different kinds of piston engines have different characteristics, but may have the same underlying functions associated with it (e.g., how many pistons in the engine, ignition sequences, lubrication, etc.). To access each of these functions in any piston engine object, a programmer would call the same functions with the same names, but each type of piston engine may have different/overriding implementations of functions behind the same name. This ability to hide different implementations of a function behind the same name is called polymorphism and it greatly simplifies communication among objects.

[0077] With the concepts of composition-relationship, encapsulation, inheritance and polymorphism, an object can represent just about anything in the real world. In fact, one's logical perception of the reality is the only limit on determining the kinds of things that can become objects in object-oriented software. Some typical categories are as follows:

[0078] Objects can represent physical objects, such as automobiles in a traffic-flow simulation, electrical components in a circuit-design program, countries in an economics model, or aircraft in an air-traffic-control system.

[0079] Objects can represent elements of the computer-user environment such as windows, menus or graphics objects.

[0080] An object can represent an inventory, such as a personnel file or a table of the latitudes and longitudes of cities.

[0081] An object can represent user-defined data types such as time, angles, and complex numbers, or points on the plane.

[0082] With this enormous capability of an object to represent just about any logically separable matters, OOP allows the software developer to design and implement a computer program that is a model of some aspects of reality, whether that reality is a physical entity, a process, a system, or a composition of matter. Since the object can represent anything, the software developer can create an object which can be used as a component in a larger software project in the future.

[0083] If 90% of a new OOP software program consists of proven, existing components made from preexisting reusable objects, then only the remaining 10% of the new software project has to be written and tested from scratch. Since 90% already came from an inventory of extensively tested reusable objects, the potential domain from which an error could originate is 10% of the program. As a result, OOP enables software developers to build objects out of other, previously built objects.

[0084] This process closely resembles complex machinery being built out of assemblies and sub-assemblies. OOP technology, therefore, makes software engineering more like hardware engineering in that software is built from existing components, which are available to the developer as objects. All this adds up to an improved quality of the software as well as an increased speed of its development.

[0085] Programming languages are beginning to fully support the OOP principles, such as encapsulation, inheritance, polymorphism, and composition-relationship. With the advent of the C++ language, many commercial software developers have embraced OOP. C++ is an OOP language that offers a fast, machine-executable code. Furthermore, C++ is suitable for both commercial-application and systems-programming projects. For now, C++ appears to be the most popular choice among many OOP programmers, but there is a host of other OOP languages, such as Smalltalk, Common Lisp Object System (CLOS), and Eiffel. Additionally, OOP capabilities are being added to more traditional popular computer programming languages such as Pascal.

[0086] The benefits of object classes can be summarized, as follows:

[0087] Objects and their corresponding classes break down complex programming problems into many smaller, simpler problems.

[0088] Encapsulation enforces data abstraction through the organization of data into small, independent objects that can communicate with each other. Encapsulation protects the data in an object from accidental damage, but allows other objects to interact with that data by calling the object's member functions and structures.

[0089] Subclassing and inheritance make it possible to extend and modify objects through deriving new kinds of objects from the standard classes available in the system. Thus, new capabilities are created without having to start from scratch.

[0090] Polymorphism and multiple inheritance make it possible for different programmers to mix and match characteristics of many different classes and create specialized objects that can still work with related objects in predictable ways.

[0091] Class hierarchies and containment hierarchies provide a flexible mechanism for modeling real-world objects and the relationships among them.

[0092] Libraries of reusable classes are useful in many situations, but they also have some limitations. For example:

[0093] Complexity. In a complex system, the class hierarchies for related classes can become extremely confusing, with many dozens or even hundreds of classes.

[0094] Flow of control. A program written with the aid of class libraries is still responsible for the flow of control (i.e., it must control the interactions among all the objects created from a particular library). The programmer has to decide which functions to call at what times for which kinds of objects.

[0095] Duplication of effort. Although class libraries allow programmers to use and reuse many small pieces of code, each programmer puts those pieces together in a different way. Two different programmers can use the same set of class libraries to write two programs that do exactly the same thing but whose internal structure (i.e., design) may be quite different, depending on hundreds of small decisions each programmer makes along the way. Inevitably, similar pieces of code end up doing similar things in slightly different ways and do not work as well together as they should.

[0096] Class libraries are very flexible. As programs grow more complex, more programmers are forced to reinvent basic solutions to basic problems over and over again. A relatively new extension of the class library concept is to have a framework of class libraries. This framework is more complex and consists of significant collections of collaborating classes that capture both the small scale patterns and major mechanisms that implement the common requirements and design in a specific application domain. They were first developed to free application programmers from the chores involved in displaying menus, windows, dialog boxes, and other standard user interface elements for personal computers.

[0097] Frameworks also represent a change in the way programmers think about the interaction between the code they write and code written by others. In the early days of procedural programming, the programmer called libraries provided by the operating system to perform certain tasks, but basically the program executed down the page from start to finish, and the programmer was solely responsible for the flow of control. This was appropriate for printing out paychecks, calculating a mathematical table, or solving other problems with a program that executed in just one way.

[0098] The development of graphical user interfaces began to turn this procedural programming arrangement inside out. These interfaces allow the user, rather than program logic, to drive the program and decide when certain actions should be performed. Today, most personal computer software accomplishes this by means of an event loop which monitors the mouse, keyboard, and other sources of external events and calls the appropriate parts of the programmer's code according to actions that the user performs. The programmer no longer determines the order in which events occur. Instead, a program is divided into separate pieces that are called at unpredictable times and in an unpredictable order. By relinquishing control in this way to users, the developer creates a program that is much easier to use. Nevertheless, individual pieces of the program written by the developer still call libraries provided by the operating system to accomplish certain tasks, and the programmer must still determine the flow of control within each piece after it's called by the event loop. Application code still “sits on top of” the system.

[0099] Even event loop programs require programmers to write a lot of code that should not need to be written separately for every application. The concept of an application framework carries the event loop concept further. Instead of dealing with all the nuts and bolts of constructing basic menus, windows, and dialog boxes and then making these things all work together, programmers using application frameworks start with working application code and basic user interface elements in place. Subsequently, they build from there by replacing some of the generic capabilities of the framework with the specific capabilities of the intended application.

[0100] Application frameworks reduce the total amount of code that a programmer has to write from scratch. However, because the framework is really a generic application that displays windows, supports copy and paste, and so on, the programmer can also relinquish control to a greater degree than event loop programs permit. The framework code takes care of almost all event handling and flow of control, and the programmer's code is called only when the framework needs it (e.g., to create or manipulate a proprietary data structure).

[0101] A programmer writing a framework program not only relinquishes control to the user (as is also true for event loop programs), but also relinquishes the detailed flow of control within the program to the framework. This approach allows the creation of more complex systems that work together in interesting ways, as opposed to isolated programs, having custom code, being created over and over again for similar problems.

[0102] Thus, as is explained above, a framework basically is a collection of cooperating classes that make up a reusable design solution for a given problem domain. It typically includes objects that provide default behavior (e.g., for menus and windows), and programmers use it by inheriting some of that default behavior and overriding other behavior so that the framework calls application code at the appropriate times.

[0103] There are three main differences between frameworks and class libraries:

[0104] Behavior versus protocol. Class libraries are essentially collections of behaviors that you can call when you want those individual behaviors in your program. A framework, on the other hand, provides not only behavior but also the protocol or set of rules that govern the ways in which behaviors can be combined, including rules for what a programmer is supposed to provide versus what the framework provides.

[0105] Call versus override. With a class library, the code the programmer instantiates objects and calls their member functions. It's possible to instantiate and call objects in the same way with a framework (i.e., to treat the framework as a class library), but to take full advantage of a framework's reusable design, a programmer typically writes code that overrides and is called by the framework. The framework manages the flow of control among its objects. Writing a program involves dividing responsibilities among the various pieces of software that are called by the framework rather than specifying how the different pieces should work together.

[0106] Implementation versus design. With class libraries, programmers reuse only implementations, whereas with frameworks, they reuse design. A framework embodies the way a family of related programs or pieces of software work. It represents a generic design solution that can be adapted to a variety of specific problems in a given domain. For example, a single framework can embody the way a user interface works, even though two different user interfaces created with the same framework might solve quite different interface problems.

[0107] Thus, through the development of frameworks for solutions to various problems and programming tasks, significant reductions in the design and development effort for software can be achieved. A preferred embodiment of the invention utilizes HyperText Markup Language (HTML) to implement documents on the Internet together with a general-purpose secure communication protocol for a transport medium between the client and the Newco. HTTP or other protocols could be readily substituted for HTML without undue experimentation. Information on these products is available in T. Berners-Lee, D. Connoly, “RFC 1866: Hypertext Markup Language—2.0” (Nov. 1995); and R. Fielding, H, Frystyk, T. Berners-Lee, J. Gettys and J. C. Mogul, “Hypertext Transfer Protocol—HTTP/1.1: HTTP Working Group Internet Draft” (May 2, 1996). HTML is a simple data format used to create hypertext documents that are portable from one platform to another. HTML documents are SGML documents with generic semantics that are appropriate for representing information from a wide range of domains. HTML has been in use by the World-Wide Web global information initiative since 1990. HTML is an application of ISO Standard 8879; 1986 Information Processing Text and Office Systems; Standard Generalized Markup Language (SGML).

[0108] To date, Web development tools have been limited in their ability to create dynamic Web applications which span from client to server and interoperate with existing computing resources. Until recently, HTML has been the dominant technology used in development of Web-based solutions. However, HTML has proven to be inadequate in the following areas:

[0109] Poor performance;

[0110] Restricted user interface capabilities;

[0111] Can only produce static Web pages;

[0112] Lack of interoperability with existing applications and data; and

[0113] Inability to scale.

[0114] Sun Microsystem's Java language solves many of the client-side problems by:

[0115] Improving performance on the client side;

[0116] Enabling the creation of dynamic, real-time Web applications; and

[0117] Providing the ability to create a wide variety of user interface components.

[0118] With Java, developers can create robust User Interface (UI) components. Custom “widgets” (e.g., real-time stock tickers, animated icons, etc.) can be created, and client-side performance is improved. Unlike HTML, Java supports the notion of client-side validation, offloading appropriate processing onto the client for improved performance. Dynamic, real-time Web pages can be created. Using the above-mentioned custom UI components, dynamic Web pages can also be created.

[0119] Sun's Java language has emerged as an industry-recognized language for “programming the Internet.” Sun defines Java as: “a simple, object-oriented, distributed, interpreted, robust, secure, architecture-neutral, portable, high-performance, multithreaded, dynamic, buzzword-compliant, general-purpose programming language. Java supports programming for the Internet in the form of platform-independent Java applets.” Java applets are small, specialized applications that comply with Sun's Java Application Programming Interface (API) allowing developers to add “interactive content” to Web documents (e.g., simple animations, page adornments, basic games, etc.). Applets execute within a Java-compatible browser (e.g., Netscape Navigator) by copying code from the server to client. From a language standpoint, Java's core feature set is based on C++. Sun's Java literature states that Java is basically, “C++ with extensions from Objective C for more dynamic method resolution.”

[0120] Another technology that provides similar function to JAVA is provided by Microsoft and ActiveX Technologies, to give developers and Web designers wherewithal to build dynamic content for the Internet and personal computers. ActiveX includes tools for developing animation, 3-D virtual reality, video and other multimedia content. The tools use Internet standards, work on multiple platforms, and are being supported by over 100 companies. The group's building blocks are called ActiveX Controls, small, fast components that enable developers to embed parts of software in hypertext markup language (HTML) pages. ActiveX Controls work with a variety of programming languages including Microsoft Visual C++, Borland Delphi, Microsoft Visual Basic programming system and, in the future, Microsoft's development tool for Java, code named “Jakarta.” ActiveX Technologies also includes ActiveX Server Framework, allowing developers to create server applications. One of ordinary skill in the art readily recognizes that ActiveX could be substituted for JAVA without undue experimentation to practice the invention.

[0121] Network-Configurable Hardware

[0122] This section will detail the development of a flexible multimedia device according to an illustrative embodiment of the present invention using hardware that can be reconfigured over a network connection and runs software applications built directly in silicon.

[0123] The illustrative platform developed for this purpose is called the Multimedia Terminal (MMT). It features no dedicated stored program and no Central Processing Unit (CPU). Instead, programs are implemented in Field Programmable Gate Arrays (FPGA) which are used both to control peripherals and to process data in order to create CPU-like flexibility using only reconfigurable logic and a software design methodology.

[0124] FPGAs can be used to create soft hardware that runs applications without the overhead associated with microprocessors and operating systems. Such hardware can be totally reconfigured over a network connection to provide enhancements, fixes, or a completely new application. Reconfigurability avoids obsolescence by allowing the flexibility to support evolving standards and applications not imagined when hardware is designed. This also allows manufacturers to use Internet Reconfigurable Logic to remotely access and change their hardware designs at any time regardless of where the units reside.

[0125] The MMT according to one exemplary embodiment of the present invention achieves flexible reconfigurability by using two independent one-million gate Xilinx XCV1000 Virtex FPGAs. One of the FPGAs remains statically configured with networking functionality when the device is switched on. The other FPGA is reconfigured with data provided by the master. The two FPGAs communicate directly via a 36-bit bus with 4 bits reserved for handshaking and two 16-bit unidirectional channels as set forth in U.S. patent application entitled SYSTEM, METHOD, AND ARTICLE OF MANUFACTURE FOR DATA TRANSFER ACROSS CLOCK DOMAINS, Attorney Docket Number EMB1P015 and filed Jan. 29, 2001 and assigned to common assignee, and which is incorporated herein by reference for all purposes. The protocol ensures that reliable communication is available even when the two FPGAs are being clocked at different speeds.

[0126] The other components of the MMT are an LCD touch screen, audio chip, 10-Mbps Ethernet, parallel and serial ports, three RAM banks and a single non-volatile flash memory chip.

[0127] FPGA reconfiguration can be performed by using one of two methods. The first method implements the Xilinx selectmap programming protocol on the static FPGA which can then program the other. The second method supplies reconfiguration data from the network interface or from the flash memory on the MMT. Reconfiguration from flash memory is used only to load the GUI for a voice-over-internet protocol (VOIP) telephone into the slave FPGA upon power-up, when an application has finished, or when configuration via the network fails. Network-based reconfiguration uses the Hypertext Transfer Protocol (HTTP) over a TCP connection to a server. A text string containing a file request is sent by the MMT to the server which then sends back the reconfiguration data (a bitfile).

[0128] There has thus been presented a flexible architecture that can run selected applications in an FPGA. Now will be described methods ofr writing all those applications and how to do it in a reasonable amount of time. Hardware Description Languages (HDL) are well-suited to creating interface logic and defining hardware designs with low-level timing issues. However, HDL may not be suitable for networking, VoIP, MP3s and video games.

[0129] To meet the challenges of the system described above, the MMT design can be done using Handel-C. It is based on ANSI-C and is quickly learned by anyone that has done C software development. Extensions have been put in to support parallelism, variables of arbitrary width, and other features familiar in hardware design, but it very much targets software design methodologies. Unlike some of the prior art C-based solutions that translate C into an HDL, the Handel-C compiler directly synthesizes an EDIF netlist that can be immediately placed and routed and put onto an FPGA.

[0130] The default application that runs on the illustrative embodiment of the MMT upon power-up is a Voice over Internet Protocol (VOIP) telephone complete with GUI. The voice over internet protocol consists of a call state machine, a mechanism to negotiate calls, and a Real Time Protocol (RTP) module for sound processing. A combination of messages from the GUI and the call negotiation unit are used to drive the state machine. The protocol implemented by the call negotiation unit is a subset of H.323 Faststart (including H225 and Q931). This protocol uses TCP to establish a stream-based connection between the two IP telephones. The RTP module is responsible for processing incoming sound packets and generating outgoing packets sent over UDP.

[0131] Algorithms for protocols such as RTP, TCP, IP and UDP can be derived from existing public domain C sources. The source code can be optimized to use features available in Handel-C such as parallelism; this is useful for network protocols which generally require fields in a packet header to be read in succession and which can usually be performed by a pipeline with stages running in parallel. Each stage can be tested and simulated within a single Handel-C environment and then put directly into hardware by generating an EDIF netlist. Further optimizations and tuning can be performed quickly simply by downloading the latest version onto the MMT over the network.

[0132] Because of the flexibility of the architecture and to take advantage of Internet reconfigurability, a mixed-bag of applications can be developed that all run in hardware on the MMT. Among them are a fully-functional MP3 player with GUI, several video games, and some impressive graphics demonstrations that were all developed using Handel-C. These applications are hosted as bitfiles on a server that supplies these files upon demand from the user of the MMT over a network connection.

[0133] Interface

[0134] In accordance with the invention, an intuitive interface is provided for defining and transferring configuration files from a computer to a device in reconfigurable logic

[0135] FIG. 2 is a flow diagram of a process 200 for providing an interface for transferring configuration data to a reconfigurable logic device, such as a Field Programmable Gate Array (FPGA), Programmable Logic Device (PLD), or Complex Programmable Logic Device (CPLD). In operation 202, images are presented on a display connected to a reconfigurable logic device. In operation 204, the user is allowed to input a command to configure the reconfigurable logic device by selecting one or more of the images. The configuration data is transferred from a computer to the reconfigurable logic device in operation 206 where it is used to reconfigure the reconfigurable logic device in operation 208.

[0136] Other embodiments include a touch sensitive Liquid Crystal Display (LCD), buttons presented as bitmapped images to guide a user, interactive configuration of the device and its components and provides downloading via the Internet and a wireless network.

[0137] In a preferred embodiment, the reconfigurable logic device is capable of saving the configuration data for later reuse. In another embodiment, the display is operable for inputting commands to control operation of the reconfigurable logic device.

EXAMPLE 1

[0138] FIG. 3 depicts a display 300 according to one embodiment of the present invention. The display is connected to a reconfigurable logic device, such as the one described below with respect to FIGS. 9-15. As an option, the display could be integrated with the device.

[0139] An exemplary procedure 400 for initiating the device is shown in FIG. 4. The device is connected to a network in operation 402 and a power source in operation 404. The display is calibrated in operation 406. In operation 408, on connecting power, the device boots with a default programming. In this example, the device boots as an IP phone, ready to accept/receive calls.

[0140] Referring again to FIG. 3, the display includes several bitmapped buttons with which a user can input commands for use during a session of Internet telephony. Keypad buttons 302 are used to enter IP addresses to place a call. The status window 304 displays the status of the device.

[0141] In accordance with the present invention, a hardware-based reconfigurable Internet telephony system can be provided. The system includes a first Field Programmable Gate Array (FPGA) that is configured with networking functionality. A user interface is in communication with the first FPGA for presenting information to a user and receiving commands from a user. A microphone in communication with the first FPGA receives voice data from the user. A communications port is in communication with the first FPGA and the Internet. The first FPGA is configured to provide a call state machine, a call negotiation mechanism, and a Real Time Protocol (RTP) module for sound processing. See the discussion relating to FIGS. 5-7 for more detailed information about how to place a call.

[0142] According to one embodiment of the present invention, a stream-based connection is generated between the system and another Internet telephony system. In another embodiment of the present invention, a second FPGA is configured for running a second application. In such an embodiment, the first FPGA can preferably configure the second FPGA.

[0143] In an embodiment of the present invention, the RTP module processes incoming sound packets and generates outgoing sound packets. In a preferred embodiment, the user interface includes a touch screen.

[0144] FIG. 5 depicts a process 500 for using the device to place a call. (The process flow is from top to bottom.) The number key is pressed and then the IP address to be called is entered. As the numbers are typed, they appear in the status window. Once the number is entered, the accept button 306 is pressed to make the connection. The word “calling” appears in the status window to denote that the connection is pending. Upon making the connection, “connected” appears in the status window. To end the call, the end button 308 is pressed.

[0145] FIG. 6 illustrates the process 600 to answering a call. The status window displays “incoming call” and the device may sound a tone. The user selects the accept button to answer the call. Selection of the end button terminates the call.

[0146] FIG. 7 depicts a configuration screen 700 for setting various parameters of the telephony functions. The buttons 702, 704 having the plus and minus signs are used to increase and decrease speaker volume, microphone volume, etc. Mute buttons 706 and display brightness buttons 708.

[0147] One skilled in the art will recognize that the device operates much like a traditional telephone and therefore, can include many of the features found in such telephones.

[0148] The screen shown in FIG. 3 includes several buttons other than those discussed above. Selecting the MP3 button 310 initiates a download sequence ordering the device to request configuration information to reconfigure the device to play audio in the MP3 format. Once the configuration information is received, the device reconfigures itself to play MP3 audio. See the following section, entitled “MP3 Decoder and Encoder” for more information about the MP3 functions of the present invention.

[0149] Upon reconfiguration, the display presents the screen 800 shown in FIG. 8A. The various buttons displayed include a play button 802, a stop button 804, track back and track forward buttons 806, 808, a pause button 810, a mute button 812, volume up and down buttons 814, 816 and an exit button 818 that returns to the default program, in this case, the IP telephony program. A graphical spectrum analyzer 820 and a track timer 822 can also be included.

[0150] Upon selection of the saver button 824, the configuration information is stored for reconfiguration of the device without requiring a download, if the device has access to sufficient storage for the information.

[0151] Referring again to FIG. 3, selection of the game button 312 initiates a download sequence ordering the device to request configuration information to reconfigure the device to allow playing of a game.

[0152] Audio Decoder

[0153] While the present invention can be used to decode audio data in a variety of ways and formats, the following description of the present invention will be set forth, for illustrative purposes, with a focus on decoding of MP3 audio.

[0154] The Decoder

[0155] GUI

[0156] FIG. 8A, described above, illustrates a graphical user interface for an MP3 decoder/player according to a preferred embodiment of the present invention.

[0157] Operation

[0158] FIG. 8B depicts a process 830 for providing a user interface for a decoder of audio data in the MPEG 1 Layer III (MP3) format. In operation 832, a display control program that controls operation of a touch screen display device is initiated. The touch screen is coupled to a reconfigurable logic device capable of decoding MP3 audio. In operation 834, a plurality of icons are displayed on the touch screen. A user selects one of the icons by touching the icon on the touch screen. A determination is made in operation 836 as to whether a user has touched the touch screen. If no touch is detected, a period of time is allowed to pass and another check is made. Note that the period between checks need not be uniform. Further, the checking process can be continuous, with no time period between checks. If a touch is detected, a location of the touch is determined in operation 838. The location of the touch is correlated with one of the icons in operation 840. In operation 842, a macro associated with the icon touched is called. The macro is utilized for processing a command for controlling the reconfigurable logic device. Note that the same or similar interface can be used with other similar devices, such as an encoder of audio or decoder of video data, for example.

[0159] In one embodiment of the present invention, the reconfigurable logic device includes at least one Field Programmable Gate Array (FPGA). As an option, the display control program can be implemented in the reconfigurable logic device. In other words, the display control program may be programmed in programmable logic, and/or can be software processed by a processor emulated in the reconfigurable logic device.

[0160] Preferably, the icons represent functions such as play, pause, stop, skip track forward, skip track back, and change volume. To increase speed, the icons can be positioned on bit boundary pixels. Also preferably, when the reconfigurable logic device is reconfigured to decode audio data in the MP3 format, the display control program is called.

[0161] Following are several macros that can be written in Handel C or other hardware description language for controlling the GUI and/or the MP3 decoder/player.

[0162] div10—A simple macro to divide by ten, used when calculating the track number of tracks.

[0163] reset_counters—Resets all counters to zero, to the beginning of the track.

[0164] mp3_play, mp3_stop, mp3_pause, mp3_quit,—Calls the relevant mp3 macros to stop, play, pause or quit the mp3 player.

[0165] mp3_skipf, mp3skipb—Skips forward of backwards by one track, by first stopping the current track, resetting the counters and starting the next track.

[0166] mp3_mute, mp3_volup, mp3_voldown—Calls the relevant mp3 functions to adjust the volume.

[0167] update_tracktime—uses the COUNTER_CLOCK_SPEED define to count the current track time. One second is COUNTER_CLOCK_SPEED clock cycles.

[0168] run_interface—runs the main display of the GUI. It contains macros for the display, the touch screen buttons, and the spectrum analyzers in parallel.

[0169] display—Checks the syncgen scan position for its location, and displays the relevant icon using the icon ROMs. The icons are kept as monochrome bitmaps at a scaling of the actual size. To increase speed, the icons are positioned on bit boundary pixels; scan positions can be tested by dropping the least significant pixels. The sixteen spectrum analyzers can be kept in two 8×8 ROMs, to reduce the number of individual icons.

[0170] update_buttons—This macro runs continuously. It first checks for a touch on the touch screen, then checks its location (i.e. which buttons have been pressed. It then calls the relevant macro to process the command.

[0171] mp3interface—The main GUI function. When the GUI is run from the same FPGA as other programs, it must account for time when the mp3 player is not running. There is therefore delay code whilst the mp3 is not running. When the GUI is needed, this calls the run interface macro once, which controls the rest of the GUI program.

[0172] Audio Decode

[0173] FIG. 8C illustrates a process 850 for decoding compressed audio data, such as audio data compressed in MPEG 1 Layer III (MP3) format. In operation 852, a bitstream is read utilizing reconfigurable hardware, where the bitstream includes compressed audio data. The data in the bitstream is interpreted in operation 854, and in operation 856, is decoded utilizing reconfigurable hardware. Note that the decoding hardware can be a portion of the hardware that reads the bitstream, or can be an entirely separate piece of hardware that is in communication with the reading hardware. The decoded data is quantized in operation 858. Stereo signals of the decoded data are decoded in operation 860. The decoded data is processed for output in operation 862.

[0174] In one embodiment of the present invention, the reconfigurable hardware includes one or more Field Programmable Gate Arrays (FPGAs). In another embodiment of the present invention, a processor is emulated in reconfigurable logic. The processor interprets the data in the bitstream and dequantizes the decoded data in software. The processor can also be used to control the reconfigurable hardware.

[0175] In an embodiment of the present invention, the processing of the decoded data for output includes transforming the decoded data into an intermediate form utilizing Inverse Modified Discrete Cosine Transform (IMDCT) filters, and transforming the data in the intermediate form to a final form utilizing polyphase filters.

[0176] In a preferred embodiment, several of the operations are performed in parallel in a pipeline. This makes the decoding very fast. Ideally, a locking system manages access to resources during performance of the operations.

[0177] The MP3 Decoder Algorithms

[0178] FIG. 8D illustrates the discrete modules and data flow in the MP3 decoder according to a preferred embodiment of the present invention. The MP3 decoder according to a preferred embodiment of the present invention has eight identifiable stages in producing the final audio signal. These are split between pure hardware implementations, and some software on a lightweight embedded RISC processor core, preferably implemented in Handel-C. They are: Bitstream Reader 865, Bitstream Interpreter, Huffman Decoder 866, Dequantizer, Stereo Decoding 867, Antialiasing, IMDCT 868, Polyphase filter bank.

[0179] Details of their function are outlined below:

[0180] Bitstream Reader

[0181] The bitstream reader is implemented in hardware, to allow one bitstream read to be implemented per clock cycle. Between 1 and 32 or more bits can be written per call.

[0182] Bitstream Interpreter

[0183] The code for parsing the bitstream, extracting information about the frame currently being decoded etc. is handled by the processor core. This code extracts information such as sample frequency, bitrate of the bitstream, stereo encoding method and the Huffman tables to use for extracting the audio data.

[0184] Huffman Decoder

[0185] The Huffman decoder for MP3 is implemented with a number of fixed tables, optimized for maximum compression of the audio data. The decoder is implemented in hardware, controlled by the processor. It in turn uses the bitstream reading hardware.

[0186] Dequantizer

[0187] The dequantizer takes the quantized frequency band output from the Huffman decoder, and along with scaling information encoded in the frame side- information, scales (using a large look-up table) the data into a floating-point form. This is implemented in software on the processor

[0188] Stereo Decoding

[0189] The stereo decoding algorithm takes the dequantized frame information from the processor memory bank, converts it from floating point to fixed point and decodes Mixed-Stereo signals for the filter banks.

[0190] IMDCT

[0191] A bank of IMDCT (Inverse Modified Discrete Cosine Transform) filters is used to transform the frequency data into an intermediate form before the final polyphase filtering stage.

[0192] Polyphase Filter Bank

[0193] The polyphase filter bank takes the IMDCT output and transforms the intermediate frequency data into the final sample. This is the most multiply intensive of the transformations and so has a heavily optimized algorithm.

[0194] Decoder Architecture

[0195] The MMT-based MP3 player uses the following shared resources:

[0196] Memory banks 0 and 1

[0197] Audio chip

[0198] Shared pins between the two FPGAs

[0199] Touch screen driver

[0200] One fixed-point multiplier on the FPGA.

[0201] The player has been designed so that most of the modules run in parallel in a pipeline. However there are limited resources available to be shared between these various processes. Thus a locking system has been implemented using mutual exclusion processes and the resources partitioned carefully amongst the competing processes. The bitstream reading, Huffman decoding, processor and stereo decoding have been allocated to Memory Bank 0.

[0202] The locking on Bank 0 has been designed so that the resource is automatically granted to the processor unless the other processes specifically request it. To implement this, the processor has a halt signal, so that it can run continuously until the memory is requested by one of the three other processes. The next time the processor tries to fetch a new instruction it stops, signals that it is halted and the resource lock is granted to the waiting process. On completion of the process, the halt signal is unset and the processor continues.

[0203] The filter banks require both scratch space and multiplication resources and thus both compete for Bank 1 and the multiplier.

[0204] The processor is in overall control of the hardware, deciding what parameters to pass to the filter banks and the Huffman decoder. In order to pass data to and from the various other processes, the hardware has been mapped into the address space above the physical memory (1 Meg). The hardware control logic include 16 32-bit registers, which can be used to supply parameters to the hardware, or read back data from the hardware (for instance—the Huffman tables to use for a particular frame are passed to the hardware through some of these status registers, and the total number of bits read while decoding returned in another register for the processor to read). Control logic for the hardware has also been mapped into a number of addresses. Thus to start the Huffman decoding process, the processor writes to the appropriate address and then is stalled until decoding completes. Similarly the processor writes to another address to start the filter banks, but as these can run simultaneously (not having any resources in common with which to conflict), the processor can continue immediately the start signal is sent.

[0205] The example code in FIG. 8E shows the implementation of the memory-mapped hardware control.

[0206] As well as the hardware (FPGA configuration) for the decoder, there is also an amount of code for the processor which must be loaded into the flash memory. Processing has been partitioned between the hardware and the processor according to two criteria. Firstly, some code is written for the processor because it is control-heavy but does not need to run particularly fast (thus saving space on the FPGA) but also some code has been partitioned onto the processor so that, with minor changes to the program code, the decoder can be changed so that it can handle MPEG2 audio streams—and thus be used in conduction with a video decoder for full movie playing.

[0207] Usage

[0208] The MP3 decoder core is designed to occupy one FPGA on the board set forth below in the section entitled Illustrative Reconfigurable Logic Device, and to receive commands and bitstream data from the other FPGA via communications implemented on the shared pins. The protocol is defined below as well.

[0209] When the MP3 decoder starts up, it performs internal initialization, and then sends a request for program code to the other FPGA. Having done this, it then does nothing until a command is sent. On receipt of a PLAY instruction, it will send requests for MP3 bitstream as required, and play the audio. When the audio stream is complete, the server FPGA should send a STOP command.

[0210] One skilled in the art will understand the general concepts of audio and video encoding and decoding (compressing and decompressing). For those requiring more information, detailed information about MPEG, MP3 and the MP3 decoding process (including the reference source code) is available on the Internet at: http://www.mpeg.org/.

[0211] Multimedia Device

[0212] FIG. 9A depicts a process 900 for providing a hardware-based reconfigurable multimedia device. In operation 902, a default multimedia application is initiated on a reconfigurable multimedia logic device, which can be a device similar to that discussed with respect to FIGS. 9B-15 below. A request for a second multimedia application is received from a user in operation 904. Configuration data is retrieved from a data source in operation 906, and, in operation 908, is used to configure the logic device to run the second multimedia application. In operation 910, the second multimedia application is run on the logic device.

[0213] According to the present invention, the multimedia applications can include an audio application, a video application, a voice-based application, a video game application, and/or any other type of multimedia application.

[0214] In one embodiment of the present invention, the configuration data is retrieved from a server located remotely from the logic device utilizing a network such as the Internet.

[0215] In another embodiment of the present invention, the logic device includes one or more Field Programmable Gate Arrays (FPGAs). Ideally, a first FPGA receives the configuration data and uses the configuration data to configure a second FPGA. Another embodiment of the present invention includes first and second FPGAs that are clocked at different speeds. In a preferred embodiment, the default multimedia application and the second multimedia application are both able to run simultaneously on the logic device, regardless of the number of FPGAs.

[0216] Illustrative Reconfigurable Logic Device

[0217] A reconfigurable logic device according to a preferred embodiment of the present invention includes a bidirectional 16 bit communications driver for allowing two FPGAs to talk to each other. Every message from one FPGA to the other is preceded by a 16 bit ID, the high eight bits of which identify the type of message (AUDIO, FLASH, RECONFIGURATION etc . . . ) and the low identify the particular request for that hardware (FLASH_READ etc . . . ). The id codes are processed in the header file fp0server.h, and then an appropriate macro procedure is called for each type of message (e.g. for AUDIO AudioRequest is called) which then receives and processes the main body of the communication.

[0218] Preferably, the FPGAs are allowed to access external memory. Also preferably, arbitration is provided for preventing conflicts between the FPGAs when the FPGAs access the same resource. Further, the need to stop and reinitialize drivers and hardware when passing from one FPGA to the other is removed.

[0219] As an option, shared resources can be locked from other processes while communications are in progress. This can include communications between the FPGAs and/or communication between an FPGA and the resource.

[0220] In one embodiment of the present invention, an application on one of the FPGAs is allowed to send a command to another of the FPGAs. In another embodiment of the present invention, one or more of the FPGAs is reconfigured so that it can access the resource.

[0221] In use, the server process requires a number of parameters to be passed to it. These are:

[0222] PID: Used for locking shared resources (such as the FLASH) from other processes while communications are in progress.

[0223] usendCommand, uSendLock: A channel allowing applications on FP0 to send commands to applications on FP1 and a one-bit locking variable to ensure the data is not interleaved with server-sent data.

[0224] uSoundOut, uSoundIn: Two channels mirroring the function of the audio driver. Data sent to uSoundOut will be played (assuming the correct code in FP1) out of the MMT2000 speakers, and data read from uSoundIn is the input to the MMT2000 microphone. The channels are implemented in such a way that when the sound driver blocks, the communication channel between FPGAs is not held up.

[0225] MP3Run: A one bit variable controlling the MP3 GUI. The server will activate or deactivate the MP3 GUI on receipt of commands from FP1.

[0226] ConfigAddr: A 23 bit channel controlling the reconfiguration process. When the flash address of a valid FPGA bitfile is sent to this channel, the server reconfigures FP1 with the bitmap specified.

[0227] The data transfer rate between the two FPGAs in either direction is preferably about 16 bits per 5 clock cycles (in the clock domain of the slowest FPGA), for communicating between FPGAs that may be running at different clock rates.

[0228] Several Handel-C macros which may be generated for use in various implementations of the present invention are set forth in Table 1. The document “Handel-C Language Reference Manual: version 3,” incorporated by reference above, provides more information about generating macros in Handel-C.

TABLE 1
Filename	Type	Macro Name	Purpose
Fp0server.h	Resource server	Fp0server()	Resource server for FP0 for the
			MMT2000 IPPhone/MP3
			project
Audiorequest.h	Audio Server	AudioRequest()	Audio server for allowing
			sharing of sound hardware
Flashrequest.h	Data server	FlashRequest()	Server for allowing FP1 access
			to the FLASH memory
Mp3request.h	MP3 server	MP3Request()	Server to control the MP3
			application and feed it MP3
			bitstream data when requested.
Reconfigurerequest.h	Reconfiguration	Reconfigurerequest()	Allows FP1 to request to be
	hardware		reconfigured, at an application
			exit.
Fpgacomms.h	Communications	Fpgacomms()	Implements two unidirectional
	hardware		16 bit channels for
			communicating between the
			two FPGAs

[0229] Illustrative Device Development Platform

[0230] FIG. 9B is a diagrammatic overview of a board 950 of the resource management device according to an illustrative embodiment of the present invention. It should be noted that the following description is set forth as an illustrative embodiment of the present invention and, therefore, the various embodiments of the present invention should not be limited by this description. As shown, the board can include two Xilinx Virtex™ 2000e FPGAs 952, 954, an Intel StrongARM SA1110 processor 956, a large amount of memory 958, 960 and a number of I/O ports 962. Its main features are listed below:

[0231] Two XCV 2000e FPGAs each with sole access to the following devices:

[0232] Two banks (1 MB each) of SRAM (256K×32 bits wide)

[0233] Parallel port

[0234] Serial port

[0235] ATA port

[0236] The FPGAs share the following devices:

[0237] VGA monitor port

[0238] Eight LEDs

[0239] 2 banks of shared SRAM (also shared with the CPU)

[0240] USB interface (also shared with the CPU)

[0241] The FPGAs are connected to each other through a General Purpose I/O (GPIO) bus, a 32 bit SelectLink bus and a 32 bit Expansion bus with connectors that allow external devices to be connected to the FPGAs. The FPGAs are mapped to the memory of the StrongARM processor, as variable latency I/O devices.

[0242] The Intel StrongARM SA1110 processor has access to the following:

[0243] 64 Mbytes of SDRAM

[0244] 16 Mbytes of FLASH memory

[0245] LCD port

[0246] IRDA port

[0247] Serial port

[0248] It shares the USB port and the shared SRAM with the FPGAs.

[0249] In addition to these the board also has a Xilinx XC95288XL CPLD to implement a number of glue logic functions and to act as a shared RAM arbiter, variable rate clock generators and JTAG and MultiLinx SelectMAP support for FPGA configuration.

[0250] A number of communications mechanisms are possible between the ARM processor and the FPGAs. The FPGAs are mapped into the ARM's memory allowing them to be accessed from the ARM as through they were RAM devices. The FPGAs also share two 1 MB banks of SRAM with the processor, allowing DMA transfers to be performed. There are also a number of direct connections between the FPGAs and the ARM through the ARM's general purpose I/O (GPIO) registers.

[0251] The board is fitted with 4 clocks, 2 fixed frequency and 2 PLLs. The PLLs are programmable by the ARM processor.

[0252] The ARM is configured to boot into Angel, the ARM onboard debugging monitor, on power up and this can be connected to the ARM debugger on the host PC via a serial link. This allows applications to be easily developed on the host and run on the board.

[0253] There are a variety of ways by which the FPGAs can be configured. These are:

[0254] By an external host using JTAG or MultiLinx SelectMAP

[0255] By the ARM processor, using data stored in either of the Flash RAMs or data acquired through one to the serial ports (USB, IRDA or RS232).

[0256] By the CPLD from power-up with data stored at specific locations in the FPGA FlashRAM.

[0257] By one of the other FPGAs.

[0258] Appendices A and B set forth the pin definition files for the master and slave FPGAs on the board. Appendix C describes a parallel port interface that gives full access to all the parallel port pins. Appendix D discusses a macro library for the board of the present invention.

[0259] StrongARM

[0260] The board is fitted with an Intel SA1110 Strong ARM processor. This has 64 Mbytes of SDRAM connected to it locally and 16Mbytes of Intel StrataFLASH™ from which the processor may boot. The processor has direct connections to the FPGAs, which are mapped to its memory map as SRAM like variable latency I/O devices, and access to various I/O devices including USB, IRDA, and LCD screen connector and serial port. It also has access to 2MB of SRAM shared between the processor and the FPGAs.

[0261] Memory Map

[0262] The various devices have been mapped to the StrongARM memory locations as shown in Table 2:

TABLE 2
Address Location Contents
0x00000000       Flash Memory 16 MB 16 bits wide.
0x08000000       CPLD see CPLD section for list of registers
0x10000000       Shared RAM bank 1 256K words x32
0x18000000       Shared RAM bank 0 256K words x32
0x40000000       FPGA access (nCS4)
0x48000000       FPGA access (nCS5)
0xC0000000       SDRAM bank 0
0xD0000000       SDRAM bank 1

[0263] The suggested settings for the StrongARM's internal memory configuration registers are shown in Table 3:

TABLE 3
Register Value
MDCNFG   0x A165 A165
MDREF    0x 8230 02E1
MDCADS0  0x 5555 5557
MDCAS1   0x 5555 5555
MDCAS2   0x 5555 5555
MSC0     0x 2210 4B5C
MSC1     0x 0009 0009
MSC2     0x 2210 2210

[0264] Where the acronyms are defined as:

[0265] MDCNFG—DRAM configuration register

[0266] MSC0,1,2—Static memory control registers for banks 0,1,2

[0267] MDREF—DRAM refresh control register

[0268] MDCAS—CAS rotate control register for DRAM banks

[0269] The CPU clock should be set to 191.7 MHz (CCF=9). Please refer to the StrongARM Developers Manual, available from Intel Corporation, for further information on how to access these registers.

[0270] FLASH Memory

[0271] The Flash RAM is very slow compared to the SRAM or SDRAM. It should only be used for booting from; it is recommended that code be copied from Flash RAM to SDRAM for execution. If the StrongARM is used to update the Flash RAM contents then the code must not be running from the Flash or the programming instructions in the Flash will get corrupted.

[0272] SDRAM

[0273] A standard 64 MB SDRAM SODIMM is fitted to the board and this provides the bulk of the memory for the StrongARM. Depending upon the module fitted the SDRAM may not appear contiguous in memory.

[0274] Shared RAM banks

[0275] These RAM banks are shared with both FPGAs. This resource is arbitrated by the CPLD and may only be accessed once the CPLD has granted the ARM permission to do so. Requesting and receiving permission to access the RAMs is carried out through CPLD register Ox 10. Refer to the CPLD section of this document for more information about accessing the CPLD and its internal registers from the ARM processor. See Appendix D.

[0276] FPGA Access

[0277] The FPGAs are mapped to the ARM's memory and the StrongARM can access the FPGAs directly using the specified locations. These locations support variable length accesses so the FPGA is able to prevent the ARM from completing the access until the FPGA is ready to receive or transmit the data. To the StrongARM these will appear as static memory devices, with the FPGAs having access to the Data, Address and Chip Control signals of the RAMs.

[0278] The FPGAs are also connected to the GPIO block of the processor via the SAIO bus. The GPIO pins map to the SAIO bus is shown in Table 4.

TABLE 4
GPIO pins SAIO lines
0, 1      0, 1
10, 11    2, 3
17-27     4-14

[0279] Of these SAIO[0:10] connect to the FPGAs and SAIO[0:14] connect to connector CN25 on the board. The FPGAs and ARM are also able to access 2 MB of shared memory, allowing DMA transfers between the devices to be performed.

[0280] I/O Devices

[0281] The following connectors are provided:

[0282] LCD Interface connector with backlight connector

[0283] IRDA connector (not 5V tolerant)

[0284] GPIO pins (not 5V tolerant)

[0285] Serial port

[0286] Reset button to reboot the StrongARM

[0287] The connections between these and the ARM processor are defined below in Tables 5-8:

TABLE 5
ARM - LCD connections (CN27)
	LCD connector
	pin no.	ARM pin	Description
	10..6	LCD0..4	BLUE0..4
	18..16	LCD5..7	GREEN0..2
	15..13	GPIO2..GPIO4	GREEN3..5
	24..20	GPIO5..GPIO9	RED0..RED4
	27	LCD_FCLK	16
	28	LCD_LCLK	17
	29	LCD_PCLK	18
	4	LCD_BIAS	19
	2, 3, (1)		+5V
	(1), 5, 11, 12, 19,		GND
	25, 26, 30

[0288]

TABLE 6
ARM IRDA connections (CN8A)
	IRDA
	connector pin no.	ARM pin	Description
	2	RxD2
	1	TxD2
	3	GPIO12
	4	GPIO13
	5	GPIO14
	6, 8		GND
	7		+3.3V

[0289]

TABLE 7
ARM GPIO - CN20AP connections
CN20AP pin no. GPIO pins
2, 3           0, 1
4, 5           10, 11
6-16           17-27
17, 19         +3.3V
18, 20         GND

[0290]

TABLE 8
ARM - Serial Port connections (CN23)
	Serial Port
	connector pin no.	ARM pin	Description
	2	RxD1
	8	RxD3
	3	TxD1
	7	TxD3
	1, 4, 6, 9		Not connected
	5		GND

[0291] The serial port is wired in such away that two ports are available with a special lead if handshaking isn't required.

[0292] Angel

[0293] Angel is the onboard debug monitor for the ARM processor. It communicates with the host PC over the serial port (a null modem serial cable will be required). The ARM is setup to automatically boot into Angel on startup—the startup code in the ARM's Flash RAM will need to be changed if this is not required.

[0294] When Angel is in use 32 MBs of SDRAM are mapped to 3x00000000 in memory and are marked as cacheable and bufferable (except the top 1 MB). The Flash memory is remapped to 0x40000000 and is read only and cacheable. The rest of memory is mapped one to one and is not cacheable or bufferable.

[0295] Under Angel it is possible to run the FPGA programmer software which takes a bitfile from the host machine and programs the FPGAs with it. As the .bit files are over 1 MB in size and a serial link is used for the data transfer this is however a very slow way of configuring the FPGAs.

[0296] Virtex FPGA's

[0297] Two Virtex 2000e FPGAs are fitted to the board. They may be programmed from a variety of sources, including at power up from the FLASH memory. Although both devices feature the same components they have different pin definitions; Handel-C header files for the two FPGAs are provided.

[0298] One of the devices has been assigned ‘Master’, the other ‘Slave’. This is basically a means of identifying the FPGAs, with the Master having priority over the Slave when requests for the shared memory are processed by the CPLD. The FPGA below the serial number is the Master.

[0299] One pin on each of the FPGAs is defined as the Master/Slave define pin. This pin is pulled to GND on the Master FPGA and held high on the Slave. The pins are:

[0300] Master FPGA: C9

[0301] Slave FPGA: D33

[0302] The following part and family parameters should be used when compiling a Handel-C program for these chips:

[0303] set family=Xilinx4000E;

[0304] set part=“XV2000e-6-fg680”;

[0305] Clocks

[0306] Two socketed clock oscillator modules may be fitted to the board. CLKA is fitted with a 50 MHz oscillator on dispatch and the CLKB socket is left to be fitted by the user should other or multiple frequencies to required. A +5V oscillator module should be used for CLKB.

[0307] Two on board PLLs, VCLK and MCLK, provide clock sources between 8 MHz and 100 MHz (125 MHz may well be possible). These are programmable by the ARM processor. VCLK may also be single stepped by the ARM.

[0308] This multitude of clock sources allows the FPGAs to be clocked at different rates, or to let one FPGA have multiple clock domains.

[0309] The clocks are connected to the FPGAs, as described in Table 9 and Appendices A and B:

	TABLE 9
		Master FPGA	Slave FPGA
	Clock	pin	pin
	CLKA	A20	D21
	CLKB	D21	A20
	VCLK	AW19	AU22
	MCLK	AU22	AW19

[0310] Programming the FPGAs

[0311] The FPGAs may be programmed from a variety of sources:

[0312] Parallel III cable JTAG

[0313] MultiLinx JTAG

[0314] MultiLinx SelectMAP

[0315] ARM processor

[0316] From the other FPGA

[0317] Power up from FLASH memory ( FPGA FLASH memory section).

[0318] When using any of the JTAG methods of programming the FPGAs you must ensure that the Bitgen command is passed the option “-g startupclk:jtagclk”. You will also need a .jed file for the CPLD or a .bsd file, which may be found in “Xilinx\xc9500×1\data\xc95288XL_tq144.bsd”. The StrongARM also requires a .bsd file, which may be found on the Intel website http:H/developer.intel.com/design/ strong/bsd1/sa1110_b1.bsd. When downloaded this file will contain HTML headers and footers which will need to be removed first. Alternatively, copies of the required .bsd files are included on the supplied disks.

[0319] The JTAG chain 1000 for the board is shown in FIG. 10.

[0320] The connections when using the Xilinx Parallel III cable and the ‘JTAG Programmer’ are set forth in Table 10:

TABLE 10
Parallel III Cable JTAG
CN24 pin number JTAG Connector
1               TMS
2               cut pin
3               TDI
4               TDO
5               not used
6               TCK
7               not used
8               GND
9               POWER

[0321] With the Xilinx cables it may be easier to fit the flying ends into the Xilinx pod so that a number of cables may be connected to the board in one go.

[0322] MultiLinx JTAG

[0323] The board has support for programming using MultiLinx. CN3 is the only connector required for JTAG programming with MultiLinx and is wired up as described in Table 11. (Note that not used signals may be connected up to the MultiLinx if required.)

TABLE 11
CN3 pin number	MultiLinx	CN3 pin number	MultiLinx
1	not used	2	Vcc
3	RD(TDO)	4	GND
5	not used	6	not used
7	not used	8	not used
9	TDI	10	not used
11	TCK	12	not used
13	TMS	14	not used
15	not used	16	not used
17	not used	18	not used
19	not used	20	not used

[0324] MultiLinx SelectMAP

[0325] JP3 must be fitted when using MulitLinx SelectMap to configure the FPGAs. This link prevents the CPLD from accessing the FPGA databus to prevent bus contention. This also prevents the ARM accessing the FPGA Flash memory and from attempting FPGA programming from power up. Connectors CN3 and CN4 should be used for Master FPGA programming and CN10 and CN11 for programming the Slave FPGA. See Tables 12-13.

TABLE 12
CN4/CN10 pin		CN4/CN10 pin
number	MultiLinx	number	MultiLinx
1	not used	2	+3v3
3	not used	4	GND
5	not used	6	not used
7	not used	8	CCLK
9	not used	10	DONE
11	not used	12	not used
13	not used	14	nPROG
15	not used	16	nINIT
17	not used	18	not used
19	not used	20	not used

[0326]

TABLE 13
CN4/CN11 pin		CN4/CN11 pin
number	MultiLinx	number	MultiLinx
1	CS0	2	D0
3	not used	4	D1
5	not used	6	D2
7	not used	8	D3
9	not used	10	D4
11	not used	12	D5
13	RS(RDWR)	14	D6
15	not used	16	D7
17	DY/BUSY	18	not used
19	not used	20	not used

[0327] In practice MultiLinx SelectMap was found to be a very tiresome method of programming the FPGAs due to the large number of flying leads involved and the fact that the lack of support for multi FPGA systems means that the leads have to connected to a different connector for configuring each of the FPGA.

[0328] ARM processor

[0329] The ARM is able to program each FPGA via the CPLD. The FPGAs are set up to be configured in SelectMap mode. Please refer to the CPLD section of this document and Xilinx Datasheets on Virtex configuration for more details of how to access the programming pins of the FPGAs and the actual configuration process respectively. An ARM program for configuring the FPGAs with a .bit file from the host PC under Angel is supplied. This is a very slow process however as the file is transferred over a serial link. Data could also be acquired from a variety of other sources including USB and IRDA or the onboard Flash RAMs and this should allow an FPGA to be configured in under 0.5 seconds.

[0330] Configuring One FPGA From the Other FPGA

[0331] One FPGA is able to configure the other through the CPLD in a manner similar to when the ARM is configuring the FPGAs. Again, please refer to the CPLD section of this document and the Xilinx data sheets for more information.

[0332] Configuring on Power Up From Flash Memory

[0333] The board can be set to boot the FPGAs using configuration data stored in this memory on power up. The following jumpers should be set if the board is required to boot from the Flash RAM:

[0334] JP1 should be fitted if the Master FPGA is to be programmed from power up

[0335] JP2 should be fitted if the Slave FPGA is to be programmed from power up.

[0336] If these jumpers are used the Flash RAM needs to be organized as shown in Table 14:

	TABLE 14
	Open	Open	All of FLASH memory available for FLASH
			data
	Fitted	Open	Master FPGA configuration data to start at
			address 0x0000
	Open	Fitted	Slave FPGA configuration data to start at
			address 0x0000
	Fitted	Fitted	Master FPGA configuration data to start at
			address 0x0000 followed by slave FPGA
			configuration data.

[0337] The configuration data must be the configuration bit stream only, not the entire .bit file. The .bit file contains header information which must first be stripped out and the bytes of the configuration stream as stored in the bit file need to be mirrored—i.e. a configuration byte stored as 00110001 in the bit file needs to be applied to the FPGA configuration data pins are 10001100.

[0338] For more information on configuration of Xilinx FPGAs and the .bit format refer to the appropriate Xilinx datasheets.

[0339] FPGA FLASH Memory

[0340] 16 MB of Intel StrataFLASH™ Flash memory is available to the FPGAs. This is shared between the two FPGAs and the CLPD and is connected directly to them. The Flash RAM is much slower than the SRAMs on the board, having a read cycle time of 120 ns and a write cycle of around 80 ns.

[0341] The FPGAs are able to read and write to the memory directly, while the ARM processor has access to it via the CPLD. Macros for reading and writing simple commands to the Flash RAM's internal state machine are provided in the klib.h macro library (such as retrieving identification and status information for the RAM), but it is left up to the developer to enhance these to implement the more complex procedures such as block programming and locking. The macros provided are intended to illustrate the basic mechanism for accessing the Flash RAM.

[0342] When an FPGA requires access to the Flash RAM it is required to notify the CLPD by setting the Flash Bus Master signal low. This causes the CPLD to tri-state its Flash RAM pins to avoid bus contention. Similarly, as both FPGAs have access to the Flash RAM over a shared bus, care has to be taken that they do not try and access the memory at the same time (one or both of the two FPGAs may be damaged if they are driven against each other). It is left up to the developer to implement as suitable arbitration system if the sharing of this RAM across both FPGAs is required.

[0343] The connections between this RAM and the FPGAs are set forth in Table 15:

TABLE 15
Flash RAM pin	Master FPGA	Slave FPGA pin
FD0	C2	C2
FD1	P4	P4
FD2	P3	P3
FD3	R1	R1
FD4	AD3	AD3
FD5	AG2	AG2
FD6	AH1	AH1
FD7	AR4	AR4
FD8	B21	A21
FD9	C23	C23
FD10	A21	B21
FD11	E22	D23
FD12	B20	A22
FD13	D22	E23
FD14	C21	B22
FD15	B19	B24
FA0	A28	A14
FA1	C28	D16
FA2	B27	B15
FA3	D27	C16
FA4	A27	A15
FA5	C27	E17
FA6	B26	B16
FA7	D26	D17
FA8	C26	C17
FA9	A26	A16
FA10	D25	E18
FA11	B25	B17
FA12	C25	D18
FA13	A25	A17
FA14	D24	C18
FA15	A24	B18
FA16	B23	D19
FA17	C24	A18
FA18	A23	C19
FA19	B24	B19
FA20	B22	C21
FA21	E23	D22
FA22	A22	B20
FA23	D23	E22
nCE	C19	A23
nWF	A18	C24
STS	D19	B23
nOE	B18	C24
nBYTE	C18	B24
F bus master pin	C17	C26

[0344] Local SRAM

[0345] Each FPGA has two banks of local SRAM, arranged as 256 K words×32 bits. They have an access time of 15 ns.

[0346] In order to allow single cycle accesses to these RAMs it is recommended that the external clock rate is divided by 2 or 3 for the Handel-C clock rate. I.e. include the following line in your code:

set clock=external_divide “A20” 2; // or higher

[0347] For an external_divide 2 clock rate the RAM should be defined as:

macro expr sram_local_bank0_spec =
{
offchip = 1,
wegate = 1,
data = DATA_pins,
addr = ADDRESS_pins,
cs = { “E2”, “F1”, “J4”, “F2”,
“H3”},
we = { “H4” },
oe = { “E1” }
};

[0348] If the clock is divided by more than 2 replace the wegate parameter with

[0349] westart=2,

[0350] welength=1,

[0351] The connections to these RAMs are as follows:

TABLE 16
SRAM Pin	Master FPGA SRAM 0	Slave FPGA SRAM 0	Master FPGA SRAM 1	Slave FPGA SRAM 1
D31	W1	AA39	AT3	AR37
D30	AB4	AB35	AP3	AR39
D29	AB3	Y38	AR3	AR36
D28	W2	AB36	AT2	AT38
D27	AB2	Y39	AP4	AR38
D26	V1	AB37	AR2	AP36
D25	AA4	AA36	AT1	AT39
D24	V2	W39	AN4	AP37
D23	AA3	AA37	AR1	AP38
D22	U1	W38	AN3	AP39
D21	W3	W37	AP2	AN36
D20	U2	V39	AN2	AN38
D19	W4	W36	AP1	AN37
D18	T1	U39	AM4	AN39
D17	V3	V38	AN1	AM36
D16	T2	U38	AM3	AM38
D15	V4	V37	AL4	AM37
D14	V5	T39	AM2	AL36
D13	U3	V36	AL3	AM39
D12	R2	T38	AM1	AL37
D11	U4	V35	AL2	AL38
D10	P1	R39	AL1	AK36
D9	U5	U37	AK4	AL39
D8	P2	U36	AK2	AK37
D7	T3	R38	AK3	AK38
D6	N1	U35	AK1	AJ36
D5	N2	P39	AJ4	AK39
D4	T4	T37	AJ1	AJ37
D3	M1	P38	AJ3	AJ38
D2	R3	T36	AH2	AH37
D1	M2	N39	AJ2	AJ39
D0	R4	N38	AH3	AH38
A17	L1	R37	AG1	AH39
A16	L2	M39	AG4	AG38
A15	N3	R36	AF2	AG36
A14	K1	M38	AG3	AG39
A13	N4	P37	AF1	AG37
A12	K2	L39	AF4	AF39
A11	M3	P36	AF3	AF36
A10	J1	N37	AE2	AE38
A9	L3	L38	AE4	AF37
A8	J2	N36	AE	AF38
A7	L4	K39	AE3	AE39
A6	H1	M37	AD2	AE36
A5	K3	K38	AD4	AD38
A4	H2	L37	AD1	AE37
A3	K4	J39	AC1	AD39
A2	G1	L36	AB1	AD36
A1	G2	J38	AC5	AC38
A0	J3	K37	AA2	AC39
CS	E2, F1, J4,	J36, H38,	AB5, AC4,	AB38, AD37,
	F2, H3	J37, K36,	AA1, AC3,	AB39, AC35,
		H39	Y1	AC37
WE	H4	G38	Y2	AA38
OE	E1	G39	AC2	AC36
D31	W1	AA39	AT3	AR37

[0352] Shared SRAM

[0353] Each FPGA has access two banks of shared SRAM, again arranged as 256K words×32 bits. These have a 16 ns access time. A series of quick switches are used to switch these RAMs between the FPGAs and these are controlled by the CPLD which acts as an arbiter. To request access to a particular SRAM bank the REQUEST pin should be pulled low. The code should then wait until the GRANT signal is pulled low by the CPLD in response.

[0354] The Handel-C code to implement this is given below:

// define the Request and Grant interfaces for
the Shared SRAM
unsigned 1 shared_bank0_request=1;
unsigned 1 shared_bank1_request=1;
interface bus_out( )
sharedbk0reg(shared_bank0_request) with
sram_shared_bank0_request_pin;
interface bus_out( )
sharedbk1reg(shared_bank1_request) with
sram_shared_bank1_request_pin;
interface bus_clock_in(unsigned 1)
shared_bank0_grant( ) with
sram_shared_bank0_grant_pin;
interface bus_clock_in(unsigned 1)
shared_bank1_grant( ) with
sram_shared_bank1_grant_pin;
// Access to a shared RAM bank
{
shared_bank0_request=0;
while (shared_bank0_grant.in) delay;
}
// perform accesses ...
// release bank
shared_bank0_request=1;

[0355] The RAMs should be defined in the same manner as the local RAMs. (See above.)

[0356] The connections to the shared RAMs are given in Table 17:

TABLE 17
	Master FPGA	Slave FPGA	Master FPGA	Slave FPGA
Shared SRAM pin	Shared SRAM 0	Shared SRAM 0	Shared SRAM 1	Shared SRAM 1
D31	AA39	W1	AR37	AT3
D30	AB35	AB4	AR39	AP3
D29	Y38	AB3	AR36	AR3
D28	AB36	W2	AT38	AT2
D27	Y39	AB2	AR38	AP4
D26	AB37	V1	AP36	AR2
D25	AA36	AA4	AT39	AT1
D24	W39	V2	AP37	AN4
D23	AA37	AA3	AP38	AR1
D22	W38	U1	AP39	AN3
D21	W37	W3	AN36	AP2
D20	V39	U2	AN38	AN2
D19	W36	W4	AN37	AP1
D18	U39	T1	AN39	AM4
D17	V38	V3	AM36	AN1
D16	U38	T2	AM38	AM3
D15	V37	V4	AM37	AL4
D14	T39	V5	AL36	AM2
D13	V36	U3	AM39	AL3
D12	T38	R2	AL37	AM1
D11	V35	U4	AL38	AL2
D10	R39	P1	AK36	AL1
D9	U37	U5	AL39	AK4
D8	U36	P2	AK37	AK2
D7	R38	T3	AK38	AK3
D6	U35	N1	AJ36	AK1
D5	P39	N2	AK39	AJ4
D4	T37	T4	AJ37	AJ1
D3	P38	M1	AJ38	AJ3
D2	T36	R3	AH37	AH2
D1	N39	M2	AJ39	AJ2
D0	N38	R4	AH38	AH3
A17	R37	L1	AH39	AG1
A16	M39	L2	AG38	AG4
A15	R36	N3	AG36	AF2
A14	M38	K1	AG39	AG3
A13	P37	N4	AG37	AF1
A12	L39	K2	AF39	AF4
A11	P36	M3	AF36	AF3
A10	N37	J1	AE38	AE2
A9	L38	L3	AF37	AE4
A8	N36	J2	AF38	AE1
A7	K39	L4	AE39	AE3
A6	M37	H1	AE36	AD2
A5	K38	K3	AD38	AD4
A4	L37	H2	AE37	AD1
A3	J39	K4	AD39	AC1
A2	L36	G1	AD36	AB1
A1	J38	G2	AC38	AC5
A0	K37	J3	AC39	AA2
CS	J36, H39, K36,	E2, H3, F2, J4, F1	AC37, AD37,	AB5, AC3,
	H38, J37		AB38, AC35.	Y1, AA1,
			AB39	AC4
WE	G38	H4	AA38	Y2
OE	G39	E1	AC36	AC2
REQUEST	A17	A25	D18	C25
GRANT	B17	B25	E18	D25

[0357] Connections to the StrongARM Processor

[0358] The FPGAs are mapped to the StrongARMs memory as variable latency I/O devices, and are treated as by the ARM as though they were 1024 entry by 32 bit RAM devices. The address, data and control signals associated with these RAMs are attached directly to the FPGAs. The manner in which the FPGAs interact with the ARM using these signals is left to the developer.

[0359] The connections are as shown in Table 18:

TABLE 18
ARM pin	Master FPGA pin	Slave FPGA pin
ARMA9	A33	C11
ARMA8	C31	B11
ARMA7	B32	C12
ARMA6	B31	A11
ARMA5	A32	D13
ARMA4	D30	B12
ARMA3	A31	C13
ARMA2	C30	D14
ARMA1	B30	A12
ARMA0	D29	C14
ARMD30	H37	G4
ARMD29	F38	D2
ARMD28	H36	F3
ARMD27	E39	D3
ARMD26	G37	F4
ARMD25	E38	D1
ARMD24	G36	C5
ARMD23	D39	A4
ARMD22	D38	D6
ARMD21	F36	B5
ARMD20	D37	C6
ARMD19	E37	A5
ARMD18	C38	D7
ARMD17	B37	B6
ARMD16	F37	C7
ARMD15	D35	A6
ARMD14	B36	D8
ARMD13	C35	B7
ARMD12	A36	C8
ARMD11	D34	A7
ARMD10	B35	D9
ARMD9	C34	B8
ARMD8	A35	A8
ARMD7	D33	C9
ARMD6	B34	B9
ARMD5	C33	D10
ARMD4	A34	A9
ARMD3	B33	B10
ARMD2	D32	C10
ARMD1	C32	D11
ARMD0	D31	A10
ARMnWE	A30	B13
ARMnOE	C29	D15
ARMnCS4	A29	A13
ARMnCS5	B29	C15
ARMRDY	B28	B14

[0360] Some of the ARM's general purpose I/O pins are also connected to the FPGAs. These go through connector CN25 on the board, allowing external devices to be connected to them (see also ARM section). See Table 19.

	TABLE 19
	SAIO bus	ARM GPI/O	Master	Slave
	(ARMGPIO)	pins	FPGA pin	FPGA pin
	SAIO10	23	B9	B34
	SAIO9	22	D10	C33
	SAIO8	21	A9	A34
	SAIO7	20	C10	D32
	SAIO6	19	B10	B33
	SAIO5	18	D11	C32
	SAIO4	17	A10	D31
	SAIO3	11	C11	A33
	SAIO2	10	B11	C31
	SAIO1	1	C12	B32
	SAIO0	0	A11	B31

[0361] CPLD Interfacing

[0362] Listed in Table 20 are the pins used for setting the Flash Bus Master signal and FP_COMs. Refer to the CPLD section for greater detail on this.

	TABLE 20
	Bus Master pin	C17	C26
	FP_COM pins	B16, E17, A15	B26, C27, A27
	[MSB..LSB]

[0363] Local I/O Devices Available to Each FPGA

[0364] ATA port

[0365] 33 FPGA I/O pins directly connect to the ATA port. These pins have 100Ω series termination resistors which make the port 5V IO tolerant. These pins may also be used as I/O if the ATA port isn't required. See Table 21.

TABLE 21
ATA line no.	ATA port	Master FPGA	Slave FPGA pin
ATA0	1	AV4	AT33
ATA1	4	AU6	AW36
ATA2	3	AW4	AU33
ATA3	6	AT7	AV35
ATA4	5	AW5	AT32
ATA5	8	AU7	AW35
ATA6	7	AV6	AU32
ATA7	10	AT8	AV34
ATA8	9	AW6	AV32
ATA9	12	AU8	AW34
ATA10	11	AV7	AT31
ATA11	14	AT9	AU31
ATA12	13	AW7	AV33
ATA13	16	AV8	AT30
ATA14	15	AU9	AW33
ATA15	18	AW8	AU30
ATA16	17	AT10	AW32
ATA17	20	AV9	AT29
ATA18	21	AU10	AV31
ATA19	23	AW9	AU29
ATA20	25	AT11	AW31
ATA21	28	AV10	AV29
ATA22	27	AU11	AV30
ATA23	29	AW10	AU28
ATA24	31	AU12	AW30
ATA25	32	AV11	AT27
ATA26	33	AT13	AW29
ATA27	34	AW11	AV28
ATA28	35	AU13	AU27
ATA29	36	AT14	AW28
ATA30	37	AV12	AT26
ATA31	38	AU14	AV27
ATA32	39	AW12	AU26
GND	2, 19, 22, 24, 26, 30, 40

[0366] Parallel Port

[0367] A conventional 25 pin D-type connector and a 26 way box header are provided to access this port. The I/O pins have 100Ω series termination resistors which also make the port 5V I/O tolerant. These pins may also be used as I/O if the parallel port isn't required. See Table 22. See also Appendix C.

TABLE 22
PP line no.	Parallel port pin	Master FPGA pin	Slave FPGA pin
PPO0	1	A8	A35
PPO1	14	B8	C34
PPO2	2	D9	B35
PPO3	15	A7	D34
PPO4	3	C8	A36
PPO5	16	B7	C35
PPO6	4	D8	B36
PPO7	17	A6	D35
PPO8	5	C7	F37
PPO9	6	B6	B37
PPO10	7	D7	C38
PPO11	8	A5	E37
PPO12	9	C6	D37
PPG13	10	B5	F36
PPO14	11	D6	D38
PPO15	12	A4	D39
PPO16	13	C5	G36
GND	18, 19, 20, 21, 22, 23, 24, 25

[0368] Serial Port

[0369] A standard 9 pin D-type connector with a RS232 level shifter is provided. This port may be directly connected to a PC with a Null Modem cable. A box header with 5V tolerant I/O is also provided. These signals must NOT be connected to a standard RS232 interface without an external level shifter as the FPGAs may be damaged. See Table 23.

TABLE 23
Serial line no.	Serial port pin no.	Master FPGA pin	Slave FPGA pin
Serial 0 (CTS)	8 (CTS)	AV3	AT34
Serial 1 (RxD)	2 (RxD)	AU4	AU36
Serial 2 (RTS)	7 (RTS)	AV5	AU34
Serial 3 (TxD)	3 (TxD)	AT6	AV36
GND.	5
Not connected	1, 4, 6, 9

[0370] Serial Header

[0371] Each FPGA also connects to a 10 pin header (CN9/CN16). The connections are shown in Table 24:

TABLE 24
(CN9/CN16) Header pin no.	Master FPGA pin	Slave FPGA Pin
1	D1	E38
2	F4	G37
3	D3	E39
4	F3	H36
5	D2	F38
6	G4	H37
7	G3	F39
8.9	GND
10	+5V

[0372] Shared I/O Devices

[0373] These devices are shared directly between the two FPGAs and great care should be taken as to which FPGA accesses which device at any given time.

[0374] VGA Monitor

[0375] A standard 15 pin High Density connector with an on-board 4 bit DAC for each colour (Red, Green, Blue) is provided. This is connected to the FPGAs as set forth in Table 25:

TABLE 25
VGA line	Master FPGA pin	Slave FPGA pin
VGA11 (R3)	AV25	AT16
VGA10 (R2)	AT24	AW14
VGA9 (R1)	AW25	AU16
VGA8 (R0)	AU24	AV15
VGA7 (G3)	AW24	AR17
VGA6 (G2)	AW23	AW15
VGA5 (G1)	AV24	AT17
VGA4 (G0)	AV22	AU17
VGA3 (B3)	AR23	AV16
VGA2 (B2)	AW22	AR18
VGA1 (B1)	AT23	AW16
VGA0 (B0)	AV21	AT18
VGA13	AW26	AW13
VGA12	AU25	AV14

[0376] LEDs

[0377] Eight of the twelve LEDs on the board are connected directly to the FPGAs. See Table 26.

	TABLE 26
	LED	Master FPGA pin	Slave FPGA pin
	D5	AT25	AU15
	D6	AV26	AV13
	D7	AW27	AT15
	D8	AU26	AW12
	D9	AV27	AU14
	D10	AT26	AV12
	D11	AW28	AT14
	D12	AU27	AU13

[0378] GPIO Connector

[0379] A 50 way Box header with 5V tolerant I/O is provided. 32 data bits (‘E’ bus) are available and two clock signals. The connector may be used to implement a SelectLink to another FPGA. +3V3 and +5V power supplies are provided via fuses. See Table 27.

	TABLE 27
		GPI/O
	Expansion	header pin	Master	Slave FPGA
	bus line	no.	FPGA pin	pin
	E0	11	AT15	AW27
	E1	13	AV13	AV26
	E2	15	AU15	AT25
	E3	17	AW13	AW26
	E5	23	AT16	AV25
	E6	25	AW14	AT24
	E7	27	AU16	AW25
	E8	31	AV15	AU24
	E9	33	AR17	AW24
	E10	35	AW15	AW23
	E11	37	AT17	AV24
	E12	41	AU17	AV22
	E13	43	AV16	AR23
	E14	45	AR18	AW22
	E15	47	AW16	AT23
	E16	44	AT18	AV21
	E17	42	AV17	AU23
	E18	40	AU18	AW21
	E19	38	AW17	AV23
	E20	34	AT19	AR22
	E21	32	AV18	AV20
	E22	30	AU19	AW20
	E23	28	AW18	AV19
	E24	24	AU21	AU21
	E25	22	AV19	AW18
	E26	20	AW20	AU19
	E27	18	AV20	AV18
	E28	14	AR22	AT19
	E29	12	AV23	AW17
	E30	10	AW21	AU18
	E31	8	AU23	AV17
	CLKA	5 (CLK 3 on diagrams)
	CLKB	49 (CLK 4 on diagrams)
	+5V	1, 2
	+3V3	3, 4
	GND	6, 7, 9, 16, 19, 26, 29, 36, 39, 46, 48, 50

[0380] SelectLink Interface

[0381] There is another 32bit general purpose bus connecting the two FPGAs which may be used to implement a SelectLink interface to provide greater bandwidth between the two devices. The connections are set forth in Table 28:

	TABLE 28
		Master	Slave
	SelectLink Line	FPGA pin	FPGA pin
	SL0	AV28	AW11
	SL1	AW29	AT13
	SL2	AT27	AV11
	SL3	AW30	AU12
	SL4	AU28	AW10
	SL5	AV30	AU11
	SL6	AV29	AV10
	SL7	AW31	AT11
	SL8	AU29	AW9
	SL9	AV31	AU10
	SL10	AT29	AV9
	SL11	AW32	AT10
	SL12	AU30	AW8
	SL13	AW33	AU9
	SL14	AT30	AV8
	SL15	AV33	AW7
	SL16	AU31	AT9
	SL17	AT31	AV7
	SL18	AW34	AU8
	SL19	AV32	AW6
	SL20	AV34	AT8
	SL21	AU32	AV6
	SL22	AW35	AU7
	SL23	AT32	AU8
	SL24	AV35	AT7
	SL25	AU33	AW4
	SL26	AW36	AU6
	SL27	AT33	AV4
	SL28	AV36	AT6
	SL29	AU34	AV5
	SL30	AU36	AU4
	SL31	AT34	AV3

[0382] USB

[0383] The FPGAs have shared access to the USB chip on the board. As in the case of the Flash RAM, the FPGA needs to notify the CPLD that it has taken control of the USB chip by setting the USBMaster pin low before accessing the chip. For more information on the USB chip refer to the USB section of this document.

	TABLE 29
	USBMaster	D17	D26
	USBMS	C16	D27
	nRST	B15	B27
	IRQ	D16	C28
	A0	A14	A28
	nRD	B14	B28
	nWR	C15	B29
	nCS	A13	A29
	D7	D15	C29
	D6	B13	A30
	D5	C14	D29
	D4	A12	B30
	D3	D14	C30
	D2	C13	A31
	D1	B12	D30
	D0	D13	A32

[0384] CPLD

[0385] The board is fitted with a Xilinx XC95288XL CPLD which provides a number of Glue Logic functions for shared RAM arbitration, interfacing between the ARM and FPGA and configuration of the FPGAs. The later can be used to either configure the FPGAs from power up or when one FPGA re-configures the other (Refer to section ‘Programming the FPGAs’). A full listing of ABEL code contained in the CPLD can be found in Appendix D.

[0386] Shared SRAM Bank Controller

[0387] The CPLD implements a controller to manage the shared RAM banks. A Request—Grant system has been implemented to allow each SRAM bank to be accessed by one of the three devices. A priority system is employed if more than one device requests the SRAM bank at the same time.

Highest priority: ARM
                  Master FPGA
Lowest priority:  Slave FPGA

[0388] The FPGAs request access to the shared SRAM by pulling the corresponding REQUEST signals low and waiting for the CPLD to pull the GRANT signals low in response. Control is relinquished by setting the REQUEST signal high again. The ARM processor is able to request access to the shared SRAM banks via some registers within the CPLD—refer to the next section.

[0389] CPLD Registers for the ARM

[0390] The ARM can access a number of registers in the CPLD, as shown in Table 30:

TABLE 30
0x00 This is an address indirection register for register 1 which used
     for the data access.
     0 Write only FLASH Address A0-A7
     1 Write only FLASH Address A8-A15
     2 Write only FLASH Address A16-A24
     3 Read / Write FLASH data (Access time must be at least
     150 ns)
     5 Write Only USB control (RST / MS)
       D0: USB RESET
       D1: USB Master Slave
0x04 Data for register 0 address expanded data
0x08 Master FPGA access
0x0C Slave FPGA access
0x10 SRAM Arbiter
     D0: Shared SRAM bank 0 Request (high to request, low to
     relinquish)
     D1: Shared SRAM bank 1 Request (high to request, low to
     relinquish)
     D4: Shared SRAM bank 0 Granted (High Granted Low not
     Granted)
     D5: Shared SRAM bank 1 Granted (High Granted Low not
     Granted)
0x14 Status / FPGA control pins (including PLL control)
     Write
     D0: Master FPGA nPROGRAM pin
     D1: Slave FPGA nPROGRAM pin
     D2: Undefined
     D3: Undefined
     D4: PLL Serial clock pin
     D5: PLL Serial data pin
     D6: PLL Feature Clock
     D7: PLL Internal Clock select
     Read
     D0: Master FPGA DONE Signal
     D1: Slave FPGA DONE signal
     D2: FPGA INIT Signal
     D3: FLASH status Signal
     D4: Master FPGA DOUT Signal
     D5: Slave FPGA DOUT Signal
     D6: USB IRQ Signal
0x18 USB Register 0
0x1C USB Register 1

[0391] CPLD Registers for the FPGA's

[0392] The FPGAs can access the CPLD by setting a command on the FPCOM pins. Data is transferred on the FPQA (Flash RAM) databus. See Table 31.

TABLE 31
0x0 Write to Control Register
    D0: Master FPGA Program signal (inverted)
    D1: Slave FPGA Program signal (inverted)
    D2: Master FPGA chip select signal (inverted)
    D3: Slave FPGA chip select signal (inverted)
0x3 Sets configuration clock low
0x5 Read Status Register
    D0: Master FPGA DONE signal
    D1: Slave FPGA DONE signal
    D2: FPGA INIT signal
    D3: FLASH status signal
    D4: Master FPGA DOUT signal
    D5: Slave FPGA DOUT signal
    D6: USB IRQ signal
0x7 No Operation

[0393] These commands will mainly be used when one FPGA reconfigures the other. Refer to the FPGA configuration section and the appropriate Xilinx datasheets for more information.

[0394] CPLD LEDs

[0395] Four LED's are directly connected to the CPLD. These are used to indicate the following:

D0 DONE LED for the Master FPGA Flashes during programming
D1 DONE LED for the Slave FPGA Flashes during programming
D2 Not used
D3 Flashes until an FPGA becomes programmed

[0396] Other Devices

[0397] USB

[0398] The board has a SCAN Logic SL11H USB interface chip, capable of full speed 12 Mbits/s transmission. The chip is directly connected to the FPGAs and can be accessed by the ARM processor via the CLPD (refer to the CPLD section of this document for further information).

[0399] The datasheet for this chip is available at http://www.scanlogic.com/pdf/sl11h /sl11hspec.pdf

[0400] PSU

[0401] This board maybe powered from an external 12V DC power supply through the 2.1 mm DC JACK. The supply should be capable of providing at least 2.4A.

[0402] Handel-C Library Reference

[0403] Introduction

[0404] This section describes the Handel-C libraries written for the board. The klib.h library provides a number of macro procedures to allow easier access to the various devices on the board, including the shared memory, the Flash RAM, the CPLD and the LEDs. Two other libraries are also presented, parallel_port.h and serial_port.h, which are generic Handel-C libraries for accessing the parallel and serial ports and communicating over these with external devices such as a host PC.

[0405] Also described is an example program which utilizes these various libraries to implement an echo server for the parallel and serial ports.

[0406] Also described here is a host side implementation of ESL's parallel port data transfer protocol, to be used with the data transfer macros in parallel_port.h.

[0407] The klib.h Library

[0408] Shared RAM Arbitration

[0409] A request—grant mechanism is implemented to arbitrate the shared RAM between the two FPGAs and the ARM processor. Four macros are provided to make the process of requesting and releasing the individual RAM banks easier.

[0410] KRequestMemoryBank0( );

[0411] KRequestMemoryBank1( );

[0412] KReleaseMemoryBank0( );

[0413] KReleaseMemoryBank1( );

[0414] Arguments

[0415] None.

[0416] Return Values

[0417] None.

[0418] Execution Time

[0419] KRequestMemoryBank#( ) requires at least one clock cycle.

[0420] KReleaseMemoryBank#( ) takes one clock cycle.

[0421] Description

[0422] These macro procedures will request and relinquish ownership of their respective memory banks. When a request for a memory bank is made the procedure will block the thread until access to the requested bank has been granted.

[0423] Note: The request and release functions for different banks may be called in parallel with each other to gain access to or release both banks in the same cycle.

[0424] Flash RAM Macros

[0425] These macros are provided as a basis through which interfacing to the Flash RAM can be carried out. The macros retrieve model and status information from the RAM to illustrate how the read/write cycle should work. Writing actual data to the Flash RAM is more complex and the implementation of this is left to the developer.

[0426] KSetFPG,4FBM( )

[0427] KReleaseFPGAFBM( )

[0428] Arguments

[0429] None.

[0430] Return Values

[0431] None.

[0432] Execution Time

[0433] Both macros require one clock cycle.

[0434] Description

[0435] Before any communication with the Flash RAM is carried out the FPGA needs to let the CPLD know that it is taking control of the Flash RAM. This causes the CLPD to tri-state the Flash bus pins, avoiding resource contention. KSetFPGAFBM( ) sets the Flash Bus Master (FBM) signal and KReleaseFPGAFBM( ) releases it. This macro is generally called by higher level macros such as KReadFlash( ) or KWriteFlash( ).

[0436] Note: These two procedures access the same signals and should NOT be called in parallel to each other.

[0437] KEnableFlash( )

[0438] KDisableFlash( )

[0439] Arguments

[0440] None.

[0441] Return Values

[0442] None.

[0443] Execution Time

[0444] Both macros require one clock cycle.

[0445] Description

[0446] These macros raise and lower the chip-select signal of the Flash RAM and tri-state the FPGA Flash RAM lines (data bus, address bus and control signals). This is necessary if the Flash RAM is to be shared between the two FPGAs as only one chip can control the Flash at any give time. Both FPGAs trying to access the Flash RAM simultaneously can cause the FPGAs to ‘latch up’ or seriously damage the FPGAs or Flash RAM chip. This macro is generally called by higher level macros such as KReadFlash( ) or KWriteFlash( ).

[0447] Note: These macros access the same signals and should NOT be called in parallel with each other.

[0448] KWriteFlash(address, data)

[0449] KReadFlash(address, data)

[0450] Arguments

[0451] 24 bit address to be written or read.

[0452] 8 bit data byte.

[0453] Return Values

[0454] KReadFlash( ) returns the value of the location specified by address in the data parameter.

[0455] Execution Time

[0456] Both procedures take 4 cycles.

[0457] The procedures are limited by the timing characteristics of the Flash RAM device. A read cycle takes at least 120 ns, a write cycle 100 ns. The procedures have been set up for a Handel-C clock of 25 MHz.

[0458] Description

[0459] The macros read data from and write data to the address location specified in the address parameter.

[0460] Note: These macros access the same signals and should NOT be called in parallel with each other.

[0461] KSetFlashAddress (address)

[0462] Arguments

[0463] 24 bit address value.

[0464] Return Values

[0465] None.

[0466] Execution Time

[0467] This macro requires one clock cycle.

[0468] Description

[0469] The macro sets the Flash address bus to the value passed in the address parameter. This macro is used when a return value of the data at the specified location is not required, as may be the case when one FPGA is configuring the other with data from the Flash RAM since the configuration pins of the FPGAs are connected directly to the lower 8 data lines of the Flash RAM.

[0470] KReadFlashIDflash_component_ID, manufacturer_ID)

[0471] KReadFlashStatus(status)

[0472] Arguments

[0473] 8 bit parameters to hold manufacturer, component and status information.

[0474] Return Values

[0475] The macros return the requested values in the parameters passed to it.

[0476] Execution Time

[0477] KReadFlashStatus( ) requires 10 cycles,

[0478] KReadFlashID( ) requires 14 cycles.

[0479] Description

[0480] The macros retrieve component and status information from the Flash RAM. This is done by performing a series of writes and reads to the internal Flash RAM state machine.

[0481] Again, these macros are limited by the access time of the Flash RAM and the number of cycles required depends on rate the design is clocked at. These macros are designed to be used with a Handel-C clock rate of 25 MHz or less.

[0482] Although a system is in place for indicating to the CPLD that the Flash RAM is in use (by using the KSetFPGAFBM( ) and KReleaseFPGAFBM( ) macros) it is left up to the developers to devise a method of arbitration between the two FPGAs. As all the Flash RAM lines are shared between the FPGAs and there is no switching mechanism as in the shared RAM problems will arise if both FPGAs attempt to access the Flash RAM simultaneously.

[0483] Note: These macros access the same signals and should NOT be called in parallel with each other. Also note that these macros provide a basic interface for communication with the Flash RAM. For more in-depth please refer to the Flash RAM datasheet.

[0484] CPLD Interfacing

[0485] The following are macros for reading and writing to the CPLD status and control registers:

[0486] KReadCPLDStatus(status)

[0487] KWriteCPLDControl(control)

[0488] Arguments

[0489] 8 bit word

[0490] Return Values

[0491] KReadStatus( ) returns an 8 bit word containing the bits of the CPLD's status register. (Refer to the CPLD section for more information)

[0492] Execution Time

[0493] Both macros require six clock cycles, at a Handel-C clock rate of 25MHz or less.

[0494] Description

[0495] These macros read the status register and write to the control register of the CPLD.

[0496] KSetFPCOMfp_command)

[0497] Arguments

[0498] 3 bit word.

[0499] Return Values

[0500] None.

[0501] Execution Time

[0502] This macro requires three clock cycles, at a Handel-C clock rate of 25 MHz or less.

[0503] Description

[0504] This macro is provided to make the sending of FP_COMMANDs to the CPLD easier. FP_COMMANDs are used when the reconfiguration of one FPGA from the other is desired (refer to the CPLD section for more information).

[0505] The different possible fpcommand (s) are set forth in Table 32:

TABLE 32
FP_SET_IDLE      Sets CPLD to idle
FP_READ_STATUS   Read the status register of the CPLD
FP_WRITE_CONTROL Write to the control register of the CPLD
FP_CCLK_LOW      Set the configuration clock low
FP_CCLK_HIGH     Set the configuration clock high

[0506] e.g.

[0507] KSetFPCOM(FP_READ_STATUS);

[0508] KSetFPCOM(FP_SET_IDLE);

[0509] Note: These macros access the same signals and should NOT be called in parallel with each other.

[0510] LEDs

[0511] KSetLEDs(maskByte)

[0512] Arguments

[0513] 8 bit word.

[0514] Return Values

[0515] None.

[0516] Execution Time

[0517] One clock cycle.

[0518] Description

[0519] This macro procedure has been provided for controlling the LEDs on the board. The maskByte parameter is applied to the LEDs on the board, with a 1 indicating to turn a light on and a 0 to turn it off. The MSB of maskbyte corresponds to D12 and the LSB to D5 on the board.

[0520] Note: Only one of the FPGAs may access this function. If both attempt to do so the FPGAs will drive against each other and may ‘latch-up’, possibly damaging them.

[0521] Using the Parallel Port

[0522] Introduction

[0523] The library parallel_port.h contains routines for accessing the parallel port. This implements a parallel port controller as an independent process, modeled closely on the parallel port interface found on an IBM PC. The controller allows simultaneous access to the control, status and data ports (as defined on an IBM PC) of the parallel interface. These ports are accessed by reading and writing to channels into the controller process. The reads and writes to these channels are encapsulated in other macro procedures to provide an intuitive API.

[0524] FIG. 11 shows a structure of a Parallel Port Data Transmission System 1100 according to an embodiment of the present invention. An implementation of ESL's parallel data transfer protocol has also been provided, allowing data transfer over the parallel port, to and from a host computer 1102. This is implemented as a separate process which utilizes the parallel port controller layer to implement the protocol. Data can be transferred to and from the host by writing and reading from channels into this process. Again macro procedure abstractions are provided to make the API more intuitive.

[0525] A host side application for data transfer under Windows95/98 and NT is provided. Data transfer speeds of around 100 Kbytes/s can be achieved over this interface, limited by the speed of the parallel port.

[0526] Accessing the Parallel Port Directly.

[0527] The 17 used pins of the port have been split into data, control and status ports as defined in the IBM PC parallel port specification. See Table 33.

TABLE 33
Port Name          Pin number
Data Port
Data 0             2
Data 1             3
Data 2             4
Data 3             5
Data 4             6
Data 5             7
Data 6             8
Data 7             9
Status Port
nACK               10
Busy               11
Paper Empty        12
Select             13
nError             15
Control Port
nStrobe            1
nAutoFeed          14
Initialise Printer 16
(Init)
nSelectIn          17

[0528] The parallel port controller process needs to be run in parallel with those part of the program wishing to access the parallel port. It is recommended that this is done using a par{} statement in the main( ) procedure.

[0529] The controller procedure is:

[0530] parallel_port(

[0531] pp_data_send_channel,

[0532] pp_data_read_channel,

[0533] pp_control_port_read,

[0534] pp_status_port_read,

[0535] pp_status_port_write);

[0536] where the parameters are all channels through which the various ports can be accessed.

[0537] Parallel Port Macros

[0538] It is recommended that the following macros be used to access the parallel port rather than writing to the channels directly.

[0539] PpWriteData(byte)

[0540] PpReadData(byte)

[0541] Arguments

[0542] Unsigned 8 bit word.

[0543] Return Values

[0544] PpReadData( ) returns the value of the data pins in the argument byte.

[0545] Execution Time

[0546] Both macros require one clock cycle.

[0547] Description

[0548] These write the argument byte to the register controlling the data pins of the port, or return the value of the data port within the argument byte respectively, with the MSB of the argument corresponding to data[7]. Whether or not the value is actually placed on the data pins depends on the direction settings of the data pins, controlled by bit 6 of the status register.

[0549] PpReadControl(control_port)

[0550] Arguments

[0551] Unsigned 4 bit word.

[0552] Return Values

[0553] PpReadControl( ) returns the value of the control port pins in the argument byte.

[0554] Execution Time

[0555] This macro requires one clock cycle.

[0556] Description

[0557] This procedure returns the value of the control port. The 4 bit nibble is made up of [nSelect_in@Init@nAutofeed@nStrobe], where nSelect_in is the MSB.

[0558] PpReadStatus(status_port)

[0559] PpSetStatus(status_port)

[0560] Arguments

[0561] Unsigned 6 bit word.

[0562] Return Values

[0563] PpReadStatus( ) returns the value of the status port register in the argument byte.

[0564] Execution Time

[0565] This macro requires one clock cycle.

[0566] Description

[0567] These read and write to the status port. The 6 bit word passed to the macros is made up of [pp_direction@busy@nAck@PE@Select@nError], where pp_direction indicates the direction of the data pins (i.e. whether they are in send [1] or receive [0] mode). It is important that this bit is set correctly before trying to write or read data from the port using PpWriteData( ) or PpReadData( ).

[0568] Note: All of the ports may be accessed simultaneously, but only one operation may be performed on each at any given time. Calls dealing with a particular port should not be made in parallel with each other.

[0569] Transferring Data To and From the Host PC

[0570] The library parallel_port.h also contains routines for transferring data to and from a host PC using ESL's data transfer protocol. The data transfer process, pp_coms( ), which implements the transfer protocol should to be run in parallel to the parallel port controller process, again preferably in the main par{} statement. A host side implementation of the protocol, ksend.exe, is provided also.

pp_coms(pp_send_chan, channel to write data to when sending
pp_recv_chan,         channel to read data from when receiving
pp_command,           channel to write commands to
pp_error)             channel to receive error messaged from.

[0571] The following macros provide interfaces to the data transfer process:

OpenPP(error)  open the parallel port for data transfer
ClosePP(error) close the port

[0572] Note: Make sure that the host side application, ksend.exe, is running. The macros will try and handshake with the host and will block (or timeout) until a response is received. Also note that the following macros all access the same process and should NOT be called in parallel with each other.

[0573] Arguments

[0574] Unsigned 2 bit word.

[0575] Return Values

[0576] The argument will return an error code indicating the success or failure of the command.

[0577] Execution Time

[0578] This macro requires one clock cycle.

[0579] Description

[0580] These two macros open and close the port for receiving or sending data. They initiate a handshaking procedure to start communications with the host computer.

SetSendMode(error) set the port to send mode
SetRecvMode(error) set the port to receive mode

[0581] Arguments

[0582] Unsigned 2 bit word.

[0583] Return Values

[0584] The argument will return an error code indicating the success or failure of the command.

[0585] Execution Time

[0586] This macro requires one clock cycle.

[0587] Description

[0588] These set the direction of data transfer and the appropriate mode should be set before attempting to send or receive data over the port.

SendPP(byte, error) send a byte over the port
ReadPP(byte, error) read a byte from the port

[0589] Arguments

[0590] Unsigned 8 bit and unsigned 2 bit words.

[0591] Return Values

[0592] ReadP( ) returns the 8 bit data value read from the host in the byte parameter. Both macros will return an error code indicating the success or failure of the command.

[0593] Execution Time

[0594] How quickly these macros execute depend on the Host. The whole sequence of handshaking actions for each byte need to be completed before the next byte can be read or written.

[0595] Description

[0596] These two macros will send and receive a byte over the parallel port once this has been initialized and placed in the correct mode.

[0597] The procedures return a two bit error code indicating the result of the operation. These codes are defined as:

#define PP_NO_ERROR              0
#define PP_HOST_BUFFER_NOT_FINISHED 1
#define PP_OPEN_TIMEOUT          2

[0598] Note: SendPP and ReadPP will block the thread until a byte is transmitted or the timeout value is reached. If you need to do some processing while waiting for a communication use a ‘prialt’ statement to read from the global pp_recv_chan channel or write to the pp_send_chan channel.

[0599] Typical macro procedure calls during Read/Write

[0600] FIG. 12 is a flowchart that shows the typical series of procedure calls 1200 when receiving data. FIG. 13 is a flow diagram depicting the typical series of procedure calls 1300 when transmitting data.

[0601] The Ksend Application

[0602] The ksend.exe application is designed to transfer data to and from the board FPGAs over the parallel port. It implements the ESL data transfer protocol. It is designed to communicate with the pp_coms( ) process running on the FPGA. This application is still in the development stage and may have a number of bugs in it.

[0603] Two versions of the program exist, one for Windows95/98 and one for WindowsNT. The NT version requires the GenPort driver to be installed. Refer to the GenPort documentation for details of how to do this.

[0604] In its current for the ksend application is mainly intended for sending data to the board, as is done in the esl_boardtest program. It is how ever also able to accept output form the board. Again, please refer to the application note or the ksend help (invoked by calling ksend without any parameters) for further details.

[0605] Serial Port

[0606] Introduction

[0607] Each FPGA has access to a RS232 port allowing it to be connected to a host PC. A driver for transferring data to and from the FPGAs from over the serial port is contained in the file serial_port.h.

[0608] RS232A Interface

[0609] There are numerous ways of implementing RS232 interfacing, depending on the capabilities of the host and device and what cables are used. This interface is implemented for a cross wired null modem cable which doesn't require any hardware handshaking—the option of software flow control is provided, though this probably won't be necessary as the FPGA will be able to deal with the data at a much faster rate than the host PC can provide it. When soft flow control is used the host can stop and start the FPGA transmitting data by sending the XON and XOFF tokens. This is only necessary when dealing with buffers that can fill up and either side needs to be notified.

[0610] Serial Port Macros

[0611] Serial port communications have been implemented as a separate process that runs in parallel to the processes that wish to send/ receive data. FIG. 14 is a flow diagram illustrating several processes 1402, 1404 running in parallel.

[0612] The serial port controller process is

[0613] serial_port(sp_input, sp_output);

[0614] where sp_input and sp_output are n bit channels through which data can be read or written out form the port. These reads and writes are again encapsulated in separate macro procedures to provide the user with a more intuitive API.

[0615] SpReadData(byte)—read a data byte from the port

[0616] SpWriteData(byte)—write a byte to the port

[0617] Arguments

[0618] n bit words, where n is the number of data bits specified.

[0619] Return Values

[0620] SpReadData( ) returns an n bit value corresponding to the transmitted byte in the argument.

[0621] Execution Time

[0622] The execution time depends to the protocol and the baud rate being used.

[0623] Description

[0624] These procedures send and receive data over the serial port using the RS232 protocol. The exact communications protocol must be set up using a series of #defines before including the serial_port.h library. To use an 8 data bit, 1 start and 1 stop bit protocol at 115200 baud on a null modem cable with no flow control the settings would be:

#define BAUD_RATE 115200
#define START_BIT     ((unsigned 1)0)
#define STOP_BIT      ((unsigned 1)1)
#define NUM_DATA_BITS 8

[0625] Other options are:

[0626] For soft flow control:

#define SOFTFLOW
#define XON  <ASCII CHARACTER CODE>
#define XOFF <ASCII CHARACTER CODE>

[0627] RTSICTS flow control:

[0628] #define HARDFLOW

[0629] The default settings are:

Baud rate      9600
Start bit      0
Stop bit       1
Num. data bits 8
XON            17
XOFF           19
Flow control off

[0630] Any of the standard baud rate settings will work provided that the Handel-C clock rate is at least 8 times higher than the baud rate. Also ensure that the macro CLOCK_RATE is defined, this is generally found in the pin definition header for each of the FPGAs.

[0631] e.g.

[0632] #define CLOCK_RATE 25000000//define the

[0633] clock rate

[0634] Example Program

[0635] Shown here is an example Handel-C program that illustrates how to use the parallel and serial port routines found in the serial_port.h and parallel_port.h libraries. The program implements a simple echo server on the serial and parallel ports. The SetLEDs( ) function from the klib.h library is used to display the ASCII value received over the serial port on the LEDs in binary.

// Include the necessary header files
#define MASTER
#ifdef MASTER
#include “KompressorMaster.h”
#else
#include “KompressorSlave.h”
#endif
#include “stdlib.h”
#include “parallel_port.h”
#include “klib.h”
// Define the protocol and include the file
#define BAUD_RATE 9600
#define NUM_DATA_BITS 8
#define NULLMODEM
#include “serial_port.h”
/////////////////////////////
// Process to echo any data received by the parallel
port
// to verify it is working properly
macro proc EchoPP( )
{
unsigned 8 pp_data_in;
unsigned 2 error with {warn = 0};
unsigned 1 done;
OpenPP(error); // initiate contact with host
while(!done)
{
// read a byte
SetRecvMode(error);
ReadPP(pp_data_in, error);
// echo it
SetSendMode(error);
WritePP(pp_data_in, error);
}
ClosePP(error); // close connection
}
/////////////////////////////
// Process to echo any data received by the serial
port
// to verify it is working properly. We are always
// listening on the serial port so there is no need
to open it.
macro proc EchoSP( )
{
unsigned 8 serial_in_data;
while(1)
{
SpReadData(serial_in_data); // read a byte
from the serial port
SetLEDs(serial_in_data);
SpWriteData(serial_in_data); // write it
back out
}
delay; // avoid combinational cycles
}
void main(void)
{
while(1)
{
par
{
EchoPP( ); //Parallel port thread
EchoSP( ); // Serial port thread
////// Start the services ////////
// Parallel Port stuff
pp_coms(pp_send_chan, pp_recv_chan,
pp_command, pp_error);
parallel_port(pp_data_send_channel,
pp_data_read_channel,
pp_control_port_read,
pp_status_port_read,pp_status_port_write);
// Serial port stuff //
serial_port(sp_input, sp_output);
}
}
}

[0636] The code can be compiled for either FPGA by simple defining or un-defining the MASTER macro—lines 1 to 5

[0637] More Information

[0638] Useful information pertaining to the subjects of this described herein can be found in the following: The Programmable Logic Data Book, Xilinx 1996; Handel-C Preprocessor Reference Manual, Handel-C Compiler Reference Manual, and Handel-C Language Reference Manual, Embedded Solutions Limited 1998; and Xilinx Datasheets and Application notes, available from the Xilinx website http://www.xilinx.com, and which are herein incorporated by reference.

[0639] Illustrative Embodiment

[0640] According to an embodiment of the present invention, a device encapsulates the Creative MP3 encoder engine in to an FPGA device. FIG. 15 is a block diagram of an FPGA device 1500 according to an exemplary embodiment of the present invention. The purpose of the device is to stream audio data directly from a CD 1502 or CDRW into the FPGA, compress the data, and push the data to a USB host 1504 which delivers it to the OASIS(Nomad 2) decoder. The entire operation of this device is independent of a PC.

[0641] The design of the FPGA uses the “Handel-C” compiler, described above, from Embedded Solutions Limited (ESL). The EDA tool provided by ESL is intended to rapidly deploy and modify software algorithms through the use of FPGAs without the need to redevelop silicon. Therefore the ESL tools can be utilized as an alternative to silicon development and can be used in a broader range of products.

[0642] Feature Overview

[0643] The FGPA preferably contains the necessary logic for the following:

[0644] MP3 Encoder 1506

[0645] User Command Look Up Table

[0646] play

[0647] pause

[0648] eject

[0649] stop

[0650] skip song (forward/reverse)

[0651] scan song (forward/reverse)

[0652] record (rip to MP3)→OASIS Unit

[0653] ATAPI

[0654] command and control

[0655] command FIFO

[0656] data bus

[0657] command bus

[0658] (2) 64 sample FIFOs (16bit*44.100 kHz)

[0659] Serial Port (16550 UART) optionally EEPROM Interface (I2C & I2S)

[0660] USB Interface to host controller

[0661] SDRAM controller

[0662] 32-bit ARM or RISC processor

[0663] In addition to the FPGA the following is preferably provided:

[0664] USB Host/Hub controller (2 USB ports)

[0665] 4MB SDRAM

[0666] 128K EEPROM

[0667] 9-pin serial port

[0668] 6 control buttons.

[0669] 40-Pin IDE Interface for CD or CDRW

[0670] Interfaces

[0671] ATAPI (IDE) Interface

[0672] User Interface

[0673] USB Interface

[0674] Network-Based Configuration

[0675] FIG. 16 illustrates a process 1600 for network-based configuration of a programmable logic device. In operation 1602, a default application is initiated on a programmable logic device. In operation 1604, a file request for configuration data from the logic device is sent to a service located remotely from the logic device utilizing a network. The configuration data is received from the network server in operation 1606, and can be in the form of a bitfile for example. In operation 1608, the configuration data is used to configure the logic device to run a second application. The second application is run on the logic device in operation 1610.

[0676] According to one embodiment of the present invention, the logic device includes one or more Field Programmable Gate Arrays (FPGAs). Preferably, a first FPGA receives the configuration data and uses that data to configure a second FPGA. The first and second FPGAs can be clocked at different speeds.

[0677] According to another embodiment of the present invention, the default application and the second application are both able to run simultaneously on the logic device. The logic device can further include a display screen, a touch screen, an audio chip, an Ethernet device, a parallel port, a serial port, a RAM bank, a non-volatile memory, and/or other hardware components.

[0678] FIG. 17 illustrates a process 1700 for remote altering of a configuration of a hardware device. A hardware device is accessed in operation 1702 utilizing a network such as the Internet, where the hardware device is configured in reconfigurable logic. In operation 1704, a current configuration of the hardware device is detected prior to selecting reconfiguring information. Reconfiguration information is selected in operation 1706, and in operation 1708, is sent to the hardware device. In operation 1710 the reconfiguration information is used to reprogram the reconfigurable logic of the hardware device for altering a configuration of the hardware device.

[0679] The reconfiguration of the hardware device can be performed in response to a request received from the hardware device. In an embodiment of the present invention, the hardware device is accessed by a system of a manufacture of the hardware device, a vendor of the hardware device, and/or an administrator of the hardware device.

[0680] In another embodiment of the present invention, the logic device includes at least one Field Programmable Gate Array (FPGA). Preferably, a first FPGA receives the reconfiguration information and uses the reconfiguration information for configuring a second FPGA.

[0681] Illustrative Embodiment

[0682] FIG. 18 illustrates a process 1800 for processing data and controlling peripheral hardware. In operation 1802, a first Field Programmable Gate Array (FPGA) of a reconfigurable logic device is initiated. The first FPGA is configured with programming functionality for programming a second FPGA of the logic device in according with reconfiguration data. The reconfiguration data for configuring the second FPGA is retrieved in operation 1804. In operation 1806, the first FPGA is instructed to utilize the reconfiguration data to program the second FPGA to run an application. In operation 1808, the first FPGA is instructed to user the reconfiguration data to program the second FPGA to control peripheral hardware incident to running the application.

[0683] In one embodiment of the present invention, data stored in nonvolatile memory is utilized for configuring the first FPGA with the programming functionality upon initiation of the first FPGA. In another embodiment of the present invention, the configuration data is retrieved from a server located remotely from the logic device utilizing a network. The configuration data can be received in the form of a bitfile.

[0684] The first and second FPGA's can be clocked at different speeds. Preferably, the logic device also includes a display screen, a touch screen, an audio chip, an Ethernet device, a parallel port, a serial port, a RAM bank, and/or a non-volatile memory.

[0685] Further Embodiments and Equivalents

[0686] While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A method for decoding compressed audio data, comprising the steps of: (a) reading a bitstream utilizing reconfigurable hardware, wherein the bitstream includes compressed audio data; (b) interpreting the data in the bitstream; (c) decoding the data utilizing reconfigurable hardware; (d) dequantizing the decoded data; and (e) processing the decoded data for output.

2. A method as recited in claim 1, wherein the reconfigurable hardware includes at least one Field Programmable Gate Array (FPGA).

3. A method as recited in claim 1, wherein a processor is emulated in reconfigurable logic, wherein the steps of interpreting the data in the bitstream and dequantizing the decoded data are performed in software processed by the emulated processor.

4. A method as recited in claim 3, wherein the processor controls the reconfigurable hardware.

5. A method as recited in claim 1, wherein the step of processing the decoded data for output includes the steps of transforming the decoded data into an intermediate form utilizing Inverse Modified Discrete Cosine Transform (IMDCT) filters, and transforming the data in the intermediate form to a final form utilizing polyphase filters.

6. A method as recited in claim 1, wherein at least two of the steps are performed in parallel in a pipeline.

7. A method as recited in claim 6, wherein a locking system manages access to resources during performance of the steps.

8. A system for decoding compressed audio data, comprising: (a) a bitstream reader implemented in reconfigurable hardware for reading a bitstream, wherein the bitstream includes compressed audio data; (b) a bitstream interpreter for interpreting the data in the bitstream; (c) a decoder implemented in reconfigurable hardware for decoding the data utilizing reconfigurable hardware; (d) a dequantizer for dequantizing the decoded data; and (e) at least one filter bank, the at least one filter bank being for processing the decoded data for output.

9. A system as recited in claim 8, wherein the reconfigurable hardware includes at least one Field Programmable Gate Array (FPGA).

10. A system as recited in claim 8, further including a processor emulated in reconfigurable logic, wherein the bitstream interpreter and dequantizer are software modules processed by the emulated processor.

11. A system as recited in claim 10, wherein the processor controls the reconfigurable hardware.

12. A system as recited in claim 8, wherein the at least one filter bank includes Inverse Modified Discrete Cosine Transform (IMDCT) filters, and polyphase filters.

13. A system as recited in claim 8, wherein at least two of the bitstream reader, bitstream interpreter, decoder, dequantizer operate in parallel.

14. A system as recited in claim 13, further comprising a locking subsystem for managing access to resources.

15. A computer program product for decoding compressed audio data, comprising: (a) computer code for configuring reconfigurable hardware for reading a bitstream, wherein the bitstream includes compressed audio data; (b) computer code for interpreting the data in the bitstream; (c) computer code for configuring reconfigurable hardware for decoding the data; (d) computer code for dequantizing the decoded data; and (e) computer code for processing the decoded data for output.

16. A computer program product as recited in claim 15, wherein the reconfigurable hardware includes at least one Field Programmable Gate Array (FPGA).

17. A computer program product as recited in claim 15, wherein a processor is emulated in reconfigurable logic, wherein the computer code for interpreting the data in the bitstream and dequantizing the decoded data are processed by the emulated processor.

18. A computer program product as recited in claim 17, wherein the processor controls the reconfigurable hardware.

19. A computer program product as recited in claim 15, wherein the computer code for processing the decoded data for output includes computer code for transforming the decoded data into an intermediate form utilizing Inverse Modified Discrete Cosine Transform (IMDCT) filters, and computer code for transforming the data in the intermediate form to a final form utilizing polyphase filters.

20. A computer program product as recited in claim 15, wherein at least two of the computer code segments are executed in parallel.

21. A computer program product as recited in claim 20, wherein a locking system manages access to resources during decoding of the data.