Integrated circuit (IC) devices, including memory devices, are often used in computers and other electronic products (e.g., digital televisions, digital cameras, and cellular phones) to store data and other information. Multiple IC devices are often used together in a system.
Systems including multiple devices typically receive information in the form of data digits. Some of the data digits, called chip select digits, select the device that is to receive and act on the information. The chip select digits take up bandwidth and may be communicated on dedicated channels between the devices. If the data digits are transmitted in packets, the chip select digits may result in the packet having a non-binary length. In addition, read data packets do not include chip select digits, while write data packets do include chip select digits.
The inventor has discovered that the challenges noted above, as well as others, can be addressed by encoding correction digits differently depending on the device being addressed. Encoding correction digits to select a device to receive and act on the data digits transmitted as well as to provide a capability to detect and correct errors in the data digits makes it unnecessary to send separate chip select digits. This reduces the bandwidth used to transmit information to multiple devices and may reduce the number of channels over which the information is transmitted.
In this description, an algorithm is a sequence of computational acts that transform an input value, or set of values, to produce an output value, or set of values.
In this description, a data digit is an item of data that has one of two or more values. A binary data digit, also called a data bit, has one of two values, a logical one (1) or a logical zero (0). A non-binary data digit has one of three or more values. The following description refers to data digits, and embodiments of the invention described herein may be implemented with data digits or data bits.
A cyclic redundancy check (CRC) is an algorithm used to identify and correct errors in a group of data digits before they are used for their intended purpose. A computation of a CRC resembles a long division of data digits by a divisor, called a CRC polynomial, to produce a CRC remainder of data digits. An example of a CRC polynomial is:
x8+x7+x3+x2+1
The length of the CRC remainder is less than the length of the polynomial. When a CRC remainder is computed from a group of data digits to be transmitted, the CRC remainder is tacked onto the end of the data digits before transmission. The CRC remainder is used by a receiving device to identify and correct errors in the data digits. Different CRC polynomials constitute different algorithms according to various embodiments of the invention.
An error correcting code (ECC) is an algorithm used to identify and correct errors in a group of data digits before they are used for their intended purpose. Examples of ECC algorithms include, but are not limited to, a Hamming code, a Reed-Solomon code, a Bose Chaudhuri Hocquenghem (BCH) code, a binary Golay code, a ternary Golay code, a Reed-Muller code, a turbo code, and a low-density parity-check (LDPC) code. ECC digits can be calculated for data digits according to one of the above-listed codes, and are transmitted with the data digits and used by a receiving device to identify and correct errors in the data digits. Each of the above-listed codes is a different algorithm according to various embodiments of the invention.
Each of the IC dies 124, 126, and 128 may be a memory device formed of semiconductor material and includes electronic circuitry which includes respective control logic circuits 154, 156, and 158 and respective arrays 164, 166, and 168 of memory cells. The IC dies 124, 126, and 128 may communicate with each other through the channels 131-138 and with the processor 110 through the interface device 116. Other devices such as other memory devices or processors may be coupled to the interface device 116 to communicate with the IC dies 124, 126, and 128. The channels 131-138 extend through or into the IC dies 124, 126, and 128 in the stack 120. The IC dies 124, 126, and 128 may have a different order, arrangement, or orientation with respect to each other in the stack 120 according to various embodiments of the invention. The stack 120 may include more or fewer IC dies according to various embodiments of the invention.
Information exchanged between the processor 110 and the stack 120 may be controlled by a control circuit 170 in the interface device 116. The information includes one or more of data, address, and control information or other information. The control circuit 170 may control information exchanged between the processor 110 and any other device coupled to the interface device 116. Information exchanged on the channels 131-138 between the interface device 116 and the IC dies 124, 126, and 128 may be controlled by a sequencer 172. A write buffer 174 in the interface device 116 stores information to be transmitted on the channels 131-138, and information received from the channels 131-138 is stored in a read buffer 176 in the interface device 116.
The channels 131-138 may be arranged into different buses to transfer different types of information. For example, the channels 131-134 may form a data bus to transfer information representing data to be stored in or read from the arrays 164, 166, and 168. The channels 135 and 136 may form an address bus to transfer information representing an address of a location where data may be stored in the arrays 164, 166, and 168. The channels 137 and 138 may form a control bus to transfer control information to the control logic circuits 154, 156, and 158 to control operations of the stack 120. Other channels (not shown) may form a power bus to provide power to the IC dies 124, 126, and 128.
The stack 120 shown in
According to various embodiments, the stack 120 shown in
Information may be transmitted in packets between the interface device 116 and the IC dies 124, 126, and 128.
The command packet or the data packet may be received by multiple pins in each of the IC dies 124, 126, and 128 shown in
According to various embodiments, the correction digits used in the method 300 are CRC digits that are calculated differently for each of the N IC devices. A different polynomial is assigned to each of the N IC devices, and each IC device uses its own polynomial to check for error in the data digits. The controller chooses which IC device is to be the intended recipient of the data digits, called a selected IC device, and calculates CRC digits by dividing the data digits by the polynomial assigned to the selected IC device. The data digits and the CRC digits are transmitted to all N of the IC devices, and each IC device divides the data digits by its own assigned polynomial to generate its own CRC digits. Each IC device compares its own CRC digits with the CRC digits received from the controller, and only one of the IC devices is able to calculate its own CRC digits to be the same as the CRC digits received from the controller and detect no error in the data digits. The IC device detecting no error in the data digits will act in response to the data digits. Other IC devices will divide the data digits by their own polynomial, different from the polynomial used by the controller, to generate their own CRC digits that are different from the CRC digits received from the controller. These IC devices will identify an error in the data digits and send an error message to the controller to request that the data digits be retransmitted. The controller will decide that the data digits contain an error only when all N of the IC devices return an error message.
According to various embodiments, CRC digits used in the method 300 may be calculated in a different manner. CRC digits may be calculated by dividing the data digits by a polynomial and then modifying the CRC digits differently depending on the IC device that is the intended recipient of the data digits. According to various embodiments, a different quantity is added to the CRC digits for each of the N IC devices, and each IC device adds its own quantity to the CRC digits before checking the data digits for error using the modified CRC digits. The quantity may be an integer. The controller chooses which IC device is to be the intended recipient of the data digits, called a selected IC device, and adds a quantity to the CRC digits, the quantity being assigned to the selected IC device. The data digits and the CRC digits are transmitted to all N of the IC devices, and each IC device divides the data digits by the polynomial to generate a CRC remainder, and then adds its own quantity to the CRC remainder to generate its own CRC digits. Each IC device compares its own CRC digits with the CRC digits received from the controller, and only one of the IC devices is able to calculate its own CRC digits to be the same as the CRC digits received from the controller and detect no error in the data digits. The IC device detecting no error in the data digits will act in response to the data digits. Other IC devices will add a quantity to the CRC remainder different from the quantity used by the intended recipient to generate their own CRC digits that are different from the CRC digits received from the controller. These IC devices will identify an error in the data digits and send an error message to the controller to request that the data digits be retransmitted. The controller will decide that the data digits contain an error only when all N of the IC devices return an error message.
The individual activities of the methods 300 and 400 do not have to be performed in the order shown or in any particular order. Some of the activities may be repeated and others may occur only once. Some of the activities may be performed in parallel. Various embodiments may have more or fewer activities than those shown in
The stack 120 shown and described herein with reference to
One or more of the components of the system 600 may be operated according to the methods 300 or 400 shown and described with reference to
The system 600 may also include a switch 646 such as a push button switch coupled to the bus 660 and a power source 647. The switch 646 may be engaged to couple power from the power source 647 to one or more of the components of system 600 such as the processor 610 or the memory device 612.
The processor 610 may include a general-purpose processor or an application specific IC (ASIC). The processor 610 may include a single core processor or a multiple-core processor. The processor 610 may execute one or more programming commands to process information. The information may include digital output information provided by other components of system 600 such as the image sensor device 620 or the memory device 625.
Each of the memory devices 625 and 612 may include a volatile memory device, a non-volatile memory device, or a combination of both. For example, the memory device 625 may comprise a DRAM device, a static random access memory (SRAM) device, a flash memory device, or a combination of these memory devices.
Each of the memory devices 625 and 612 and/or the processor 610 may be arranged in a stack of IC dies according to the various embodiments described herein, such as the stack 120 shown and described with reference to
Some components of the system 600 may be arranged together such that the system 600 may include a system in package (SIP). For example, the memory device 612 and the processor 610 may be a part of a SIP 601 or the entire SIP 601 in which the memory device 612 may be used as a cache memory for the processor 610. The memory device 612 may be a level L1 cache, a level L2 cache, a level L3 cache, or a combination thereof. The processor 610 and the memory device 612 may communicate with each other through one or more channels 621.
The image sensor device 620 may include a complementary metal-oxide-semiconductor (CMOS) image sensor having a CMOS pixel array or charge-coupled device (CCD) image sensor having a CCD pixel array. The display 652 may include an analog display or a digital display. The display 652 may receive information from other components. For example, the display 652 may receive and display information such as text or images that is processed by one or more of the image sensor device 620, the memory device 625, the graphics controller 640, and the processor 610.
The additional circuit 645 may include circuit components used in a vehicle (not shown). The additional circuit 645 may receive information from other components to activate one or more subsystems of the vehicle. For example, the additional circuit 645 may receive information that is processed by one or more of the image sensor device 620, the memory device 625, and the processor 610 to activate one or more of an air bag system, a vehicle security alarm, and an obstacle alert system.
The systems and methods presented herein may provide increased efficiency by increasing the amount of useful information contained in digits transmitted to multiple devices. This reduces the bandwidth used to transmit the information to multiple devices and may reduce the number of channels over which the information is transmitted. This can lead to a significant performance improvement.
Any of the circuits or systems described herein may be referred to as a module. A module may comprise a circuit and/or firmware according to various embodiments.
The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will 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 claims. In addition, in the foregoing Detailed Description, it can be seen that various features are arranged together for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of one or more of the disclosed embodiments. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
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