Patent Application
20110161532
Many standards have been developed for wired serial communication. The standards allow manufacturers of serial communication hardware, firmware and software to develop products in parallel that when interfaced, couple together mechanically and electrically to provide predictable and robust exchange of information between products. As a standard becomes more accepted in the market, product manufacturers look to distinguish their products by offering variations, including communication options that compliment the accepted communication standard. However, some communication standards do not allow much deviation, and thus require different support components, such as different transceivers, to support each variation of a product certified under that standard. Finding the specific support components, and stocking each, can be cost prohibitive and limit a product manufacturer's ability to fully compete in a product market.
This document discusses, among other things, transceiver apparatus and methods for wired serial communication to a remote device. In an example, the transceiver can include an input for receiving first information, a compensation input for receiving compensation information, and an output for transmitting an output signal, including the first information, to a component coupled between the transceiver and the remote device. The transceiver can be configured to generate the output signal using the compensation information to maintain a specified signal quality at the remote device.
Another aspect of the disclosure includes a method for using an adjustable transceiver. In one example, the method includes receiving first information at an input of a transceiver. The transceiver is configured for wired serial communication to a remote device. The method also includes receiving compensation information using a compensation input of the transceiver, generating an output signal including the first information according to the compensation information, and transmitting the first information to the remote device. System examples employing an adjustable High Speed Universal Serial Bus transceiver are also provided.
The examples provided herein can be combined in any permutation or combination. This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various examples discussed in the present document.
In various examples, a transceiver includes a data port (e.g., an input), a communication port (e.g., an output) and a compensation input. The data port exchanges information with a control device, such as a processor. The information can include data received at the communication port or data for transmission out of the communication port. The communication port can receive and transmit information with a remote device. In various examples, the communication port communicates with the remote device using a wired media. The transceiver can transmit information and can be configured to receive information at the communication port consistent with one or more specified standards, for example, but not limited to, Universal Serial Bus (USB) standards.
In an example, standards can allow manufacturers to build communication interfaces that are physically and electrically compatible. Various standards provide guidelines for signal characteristics, hardware characteristics, and hardware dimensions. For example, hardware standards can include, but are not limited to, connector shapes, termination counts, termination locations, termination configurations, and connector dimensions. Some wired, serial communication guidelines provide guidelines for signal levels and signal switching rates. For example, the high-speed USB 2.0 (HS USB 2.0) specification refers to “eye” compliance for signal morphology in providing specification limits of the signal levels and signal switching rates. Manufacturers of HS USB 2.0 compatible products can obtain certification, and label and advertise such certification, by meeting the specification guidelines. However, some products with wired serial communications capabilities can include features that do not allow a transceiver for one certified device to be used in a second device and yet still comply with the certification requirements in the second device. The present inventors have recognized, among other things, that an adjustable transceiver can allow a manufacturer to use a single transceiver in a variety of products yet still meet communication compliance even though those products can include components that distort the signals transmitted and received by the transceiver.
In many products, the switch 624 can introduce distortion between a signal source, such as a wired serial communication transceiver 600, and the port 626 of the product 620. In some cases, the distortion is minor and does not interfere with communication between the product 620 and the remote device 630. However, for some wired serial communication standards, the distortion, even though minor, can prevent the product 620 from complying with, and obtaining certification of compliance for, a desired communication standard. In such cases, manufacturers can be limited to the number of features and different product lines a particular transceiver can work with and still maintain certification. Several transceivers with different transmission characteristics may need to be stocked such that the various product lines, the various features, and the various combination of features within a product line can maintain certification with a desired communication standard. Even slight design changes can change electrical characteristics of the connection between the transceiver and the port of the device. For example, modifying a printed circuit board (PCB) layout, or switching PCB suppliers, may require a different transceiver to maintain compliance between the transceiver and the port of the device. Slight changes can introduce enough distortion that the output signal no longer complies with a desired standard. Thus, small modifications can require a manufacturer to change a communication transceiver or to stock several different transceivers to maintain compliance with a desired communication standard.
A transceiver according to the present subject matter can solve these problems. In various examples, the transceiver can include a plurality of compensation settings such that a single transceiver model can work with a broad range of products requiring certification with a desired wired, serial communication standard, such as the High Speed USB 2.0 standard. In various examples, the plurality of settings can be stored in programmable memory. In some examples, the plurality of settings can be hard-coded into the transceiver. In some examples, compensation using the compensation settings can be implemented using software. In some examples, compensation using the compensation settings can be implemented using hardware. In various examples, compensation using the compensation settings can be implemented using a combination of hardware and software.
Selection of a compensation setting for a product can be accomplished using a compensation input of the adjustable transceiver. In various examples, the compensation input can include a terminal. Biasing the terminal with a first reference can select a first compensation setting for generating an output signal of the transceiver. Biasing the terminal with a second reference can select a second compensation setting for generating an output signal of the transceiver. In various examples, the compensation input can provide an indication whether a component is coupled to the output transceiver or not. A compensation setting can be selected based on configuration information received using the compensation input. Providing the ability to adjust the output signal of the transceiver can allow a manufacturer to use a single model of transceiver for a number of products. The transceiver can include a number of selectable compensation settings. In various examples, a compensation setting can be selected based on the components, or lack thereof, coupled to the transceiver. Implementation of the selected compensation setting compensates for distortion of an output signal of the transceiver caused by the components coupled to the transceiver. A compensation setting, in various examples, can be selected to maintain certification of a product according to a desired communication standard. For example, upon installation of an adjustable transceiver within a product, one or more transceiver terminals can be biased to select a particular compensation setting for the transceiver related to particular product within which the transceiver is installed.
In various examples, a selected compensation setting can alter how the serial output signal of the transceiver is generated. For example, in some products a switch can be coupled to the transceiver. The switch can allow a single port of the product to communicate a variety of information, including, but not limited to, wired serial communication information, audio information, and video information. Such a switch can introduce signal distortion. The signal distortion can cause the product to fail certification of a desired wired serial communication standard, such as the “eye” requirements of a standard. In various examples, a compensation setting of an adjustable transceiver can be selected to adjust output signal levels, such as amplitude levels, of the transceiver to maintain the “eye” shape at a remote device. In some examples, “pre-emphasis” can be used to maintain the “eye”. “Pre-emphasis” drives the output harder during the initial transition of a signal and then reduces the “pre-emphasis” as the signal transitions. Such “pre-emphasis” driving of the output signal can compensate for additional impedance introduced by a switch, for example. The amount of pre-emphasis can be different depending on the particular component coupled to the transceiver. For example, a first USB switch coupled to a transceiver can require a first pre-emphasis, or amplitude adjustment setting to maintain the “eye”, but a second USB switch coupled to the same transceiver can require a different setting to maintain the “eye”. The adjustable transceiver can be used with both switches, thus reducing the number of different transceivers a manufacturer needs to stock. Although the transceiver can compensate several different components with a particular “pre-emphasis” setting, in some situations, over driving a switch, or a PCB board, can also provide a non-compliant signal at the port of the product. Additionally, where a compensation setting causes the transceiver to drive an output signal substantially harder than is necessary, use of the product can be substantially reduced. For example, where the product is used under battery power, substantial overdriving can discharge the battery faster than a setting matched to more gently bring the signal into compliance. It is understood that other methods of compensation, in addition to “pre-emphasis” and amplitude adjustment are possible without departing from the scope of the present subject matter.
The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific examples in which the invention can be practiced. These examples are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventor also contemplates examples in which only those elements shown or described are provided. Moreover, the present inventor also contemplates examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.
All publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other examples can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed example. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. The scope of the invention should be determined with reference to the appended claims, along with the full scope of legal equivalents to which such claims are entitled.
