Method for releasing card power up status bit of SD (secure digital) memory card and hardware circuit
A hardware circuit and electrical state technology, applied in static memory, information storage, instruments, etc., can solve the problems of not fast enough software execution, not too high, etc., and achieve the effect of reducing dependence and enhancing compatibility
Active Publication Date: 2014-01-01
SHANGHAI HUAHONG INTEGRATED CIRCUIT
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- Description
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Problems solved by technology
However, not all SD hosts on the market are designed strictly in accordance with the SD protocol. Some SD hosts have a frequency much higher than 400k during the initialization authentication process. If the operating frequency of the CPU is not too high, the software execution speed Not fast enough, then the probability of the above risks will be greatly increased
Method used
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Embodiment Construction
[0014] The structural block diagram of an embodiment of the hardware circuit adopted in the method of the present invention is as shown in the figure, including:
[0015] The command receiving circuit is responsible for receiving commands issued from the SD host.
[0016] The second synchronization circuit is connected with the command receiving circuit and is responsible for synchronizing the signal of the external SD clock domain to the internal clock domain.
[0017] The latch control circuit is connected with the second synchronous circuit and the latch register, receives the card power-on status bit OCR[31] signal of the OCR register, and transmits the card power-on status bit OCR[31] signal to the latch register.
[0018] The latch register is connected with the latch control circuit and the first synchronization circuit, and is used for latching the card power-on status bit OCR[31].
[0019] The first synchronization circuit is connected with the latch register and the...
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The invention discloses a method for releasing the card power up status bit of an SD (secure digital) memory card. The method is characterized in that after receiving a command, a hardware circuit latches the card power up status bit and then releases the card power up status bit; and software inquires a latch register before switching an SD memory card status machine. The invention also discloses the hardware circuit for implementing the method. The hardware circuit comprises a command receiving circuit, a latch control circuit, a response sending circuit, a synchronous circuit and a register access circuit, wherein the command receiving circuit is in charge of receiving the command from an SD host; the latch control circuit is used for latching the card power up status bit into the register; the response sending circuit is used for returning a response to the command to the SD host; the synchronous circuit is used for processing a cross clock domain signal; and the register access circuit is used by the software to read and write the register. The method has the following beneficial effects: the card power up status bit can be correctly released; the SD memory card status machine can be correctly switched; and the initialization authentication process can be normally completed.
Description
technical field [0001] The invention relates to the field of semiconductor flash memory, in particular to a method for issuing card power-on status bits during the initial authentication process of an SD (SecureDigital Memory Card) card. The invention also relates to a hardware circuit for implementing the method. Background technique [0002] SD card is a new generation memory device based on semiconductor non-volatile flash memory (flash), which is widely used in portable devices, such as mobile phones, digital cameras, digital video cameras, personal digital assistants (PDA) and multimedia players device etc. The SD card was jointly developed by Japan's Panasonic, Toshiba and the US SanDisk in August 1999. It has the advantages of high memory capacity, fast data transmission rate, great mobility flexibility and good security. [0003] The topology of the SD card communication system is master-slave, and the SD card is a slave device controlled by the SD host. The data ...
Claims
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IPC IPC(8): G11C16/06
Inventor 张晓成
Owner SHANGHAI HUAHONG INTEGRATED CIRCUIT