KR100318214B1 - Data interface method between microcomputer and memory card - Google Patents

Abstract

The present invention relates to a data interbase method between a microcomputer and a memory card, the method comprising: transmitting a mode confirmation command of the microcomputer to the memory card; Transmitting a communication mode supported by the memory card to the microcomputer; Selecting a communication protocol corresponding to the transmitted support communication mode; And performing data communication with the memory card using the selected communication protocol, according to the type of the memory card, that is, the multimedia card or the multimedia ROM card according to the SPI method or the MC. (MMC) communication protocol can be selectively used, and the input / output port can be used as a unidirectional SPI port for high-speed data transmission or a general input / output port for bi-directional data transmission / reception according to data transmission and reception status. The variable setting is a very useful invention that can easily implement a data interface with a plurality of memory cards requiring different communication protocols using a conventional microcomputer having an SPI port.

Description

Data interface method between microcomputer and memory card

The present invention relates to a data interface method between a microcomputer and a memory card, and more particularly, a communication protocol of a different method using a conventional microcomputer having a SPI (Serial Peripheral Interface) port. A data interface method between a microcomputer and a memory card which easily implements a data interface with a plurality of required memory cards, that is, a multimedia card or a multimedia ROM card.

Recently, with the rapid development of electronic devices, especially image recording / playback devices and computers, recording media that can read and record large amounts of data more easily have been rapidly developed and proposed by many related companies. Representative recording media for which commercialization is currently being actively promoted include a memory card using a conventional flash memory as a recording medium, a so-called multimedia card (MMC).

FIG. 1 schematically shows a configuration of the multimedia card (MMC), wherein the MMC card 1 is a nonvolatile memory capable of repeatedly recording and reading data. In-flash memory 3; A controller 4 reads and writes data of the flash memory 3 and performs an interface with the connected external microcomputer 2.

The MMC card 1 configured as described above is typically manufactured in a size of 24 mm wide, 32 mm long and 1.4 mm thick, and the controller 4 is of the MMC method proposed with the MMC card development. In addition to the communication protocol (Protocol) as well as the general SPI communication protocol (Protocol), a data communication protocol is provided so that the data interface is achieved.

However, the conventional microcomputer 2 developed and commercialized so far uses only the communication protocol of the SPI method, and the input / output port provided in the microcomputer 2 is the SPP. This is a SPI dedicated port designed for SPI. On the other hand, the SPI dedicated port is a unidirectional input / output port capable of quickly transmitting or receiving data including a command, and is an MMC communication protocol requiring bidirectional data transmission and reception. There is an inadequate problem.

In addition, recently, a multimedia ROM card is being developed by Siemens, Germany's largest memory card producer. The multimedia ROM card is an MMC type. Since the data is read only by the communication protocol, there is a problem that the data interface with the multimedia ROM card becomes impossible using the conventional microcomputer 2 using the SPI communication protocol.

Therefore, the present invention was created to solve the above problems, and according to the type of the memory card, that is, the multimedia card or the multimedia ROM card, and selectively use the corresponding communication protocol, the MC (MMC) method When using a multimedia card capable of data interface only by the communication protocol of the computer, the unidirectional SPI dedicated port is switched to a general bi-directional input / output port, so that the multimedia card (MMC) as well as the multimedia ROM ( It is an object of the present invention to provide a data interface method between a microcomputer and a memory card that enables both a data interface with a ROM) card.

1 is a schematic configuration diagram of a memory card,

2A and 2 illustrate a connection state and transmission / reception data between a multimedia card and a microcomputer,

3A and 3B illustrate an operation flowchart of a data interface method between a microcomputer and a multimedia card according to the present invention;

4A and 4B illustrate a connection state and transmission / reception data of a multimedia ROM card and a microcomputer,

5 is a flowchart illustrating an operation of a data interface method between a microcomputer and a multimedia ROM card according to the present invention;

6A and 6B illustrate a data format according to the present invention.

※ Explanation of code for main part of drawing

1: memory card 2: external microcomputer

3: Flash memory 4: Controller

In accordance with another aspect of the present invention, there is provided a data interface method between a microcomputer and a memory card. The method may include: transmitting a mode check command of the microcomputer to the memory card. Transmitting to the second step; Selecting a communication protocol corresponding to the transmitted support communication mode; And performing data communication with the memory card using the selected communication protocol.

In the data interface method between the microcomputer and the memory card according to the present invention, the memory card determines whether the memory card is a multimedia card or a multimedia ROM card. If the result of the determination is a multimedia card, an SPI communication protocol is used. In the case of a multimedia ROM card, the data interface is performed using an MMC communication protocol, and the SPI port is bidirectional data depending on a data transmission or reception state. By selectively switching to a general input / output port capable of transmitting and receiving, a data interface between a multimedia card (MMC) and a multimedia ROM (ROM) card requiring different communication protocols is achieved.

Hereinafter, a data interface method with a memory card according to the present invention will be described in detail with reference to the accompanying drawings.

First, FIGS. 2A and 2B show connection states between a multimedia card (MMC) and an external micom, for example, a microcomputer provided in an image recording / playback apparatus, and transmission / reception data of an SPI port. As shown, in particular, Fig. 2A shows a connection state for reading and recording data of the MMC card 1 using a SPI communication protocol. In the SPI communication protocol, a serial clock (SPI) port using four unidirectional SPI ports (P0 to P3) is used as a connection port between the MMC card (1) and the external microcomputer (2). SCK: Serial Clock, hereinafter referred to as 'SCK'), Serial Data Output (SDO: Serial Data Out, hereinafter referred to as 'SDO'), Serial Data Input (SDI: Serial Data In, hereinafter referred to as 'SDI'). ) And card select output (CS: Card Select, hereinafter referred to as 'CS'). Hereinafter, a data interface operation with the MMC card using the SPI method will be described.

3A and 3B are an operation flowchart for a data interface with a multimedia card MMC. First, in the data write operation shown in FIG. 3A, when an external key requesting a recording operation is input to the microcomputer 2, FIG. The microcomputer 2 sets the operation mode of the video recording / reproducing apparatus to the write mode (S01), and issues a command to reset the communication protocol to the SPI method by using the MMC card. After transmitting to the controller 4 of (1), the response received from the controller 4 is checked (S02). Thereafter, the microcomputer 2 transmits a write block command for designating a data recording area of the MMC card, that is, the flash memory 3, which has been reset by the SPI method, and then the controller 4 Check the response received from (S03). As a result of the check (S04), if a normal response is received, 512 bytes, that is, one data block unit, that is, data to be recorded are transmitted in block units (S05), and a 16-bit cyclic redundancy check is performed to check for a transmission error. (CRC: Cyclic Redundancy Checking, hereinafter referred to as 'CRC'.) The code is transmitted (S06).

Subsequently, while repeating the above operation, the file end is detected (S07) and the recording operation is terminated (S08), thereby writing the data file to be written to the flash memory 3 of the MMC card. Will be done. Such a data recording operation is performed in a unidirectional SPI dedicated port for high-speed data transfer.

3B is a flowchart illustrating a data read operation. When an external key requesting a read operation is input to the microcomputer 2, the microcomputer 2 reads an operation mode of the video recording / reproducing apparatus. Mode (S11), and transmits a command to reset the communication protocol to the SPI method to the controller 4 of the MMC card 1, and then from the controller 4 Check the received response (S12). Thereafter, the microcomputer 2 retransmits a read area command (Read Block Command) for designating a data read area of the MMC card, that is, the flash memory 3, which has been reset by the SPI method, and then the controller 4 Check the response received from the (S13). As a result of the check (S14), when the normal response is received, the variable unidirectional SPI dedicated port is variably set to a general input / output port capable of bidirectional data transmission and reception (S15), and the variable set general input / output port After receiving the data read from the MMC card through a data block unit, that is, a data block unit corresponding to 512 bytes (S16), and receives a 16-bit CRC code for checking whether there is a transmission error (S17). Thereafter, while repeatedly performing the above operation, a file end received is detected (S18), and the read operation is terminated (S19), thereby reading an arbitrary data file to be read from the flash memory 3 of the MMC card ( Read). The data read operation is performed by variably setting a unidirectional SPI dedicated port to a general input / output port capable of bidirectional data transmission and reception.

In the case of the MMC card that can selectively use the SPI and MMC communication protocols, a normal microcomputer using the SPI communication protocol should be used. By variably setting the unidirectional SPI port to a general input / output port capable of bidirectional data transmission and reception, a data interface with the MMC card, that is, writing and reading operation, is performed.

Meanwhile, as described above, a data interface method with a multimedia ROM card that must use an MMC communication protocol will be described in detail with reference to the accompanying drawings.

First, FIGS. 4A and 4B show a multimedia ROM card and an external micom. For example, the connection state and the transmission data of the input / output ports between the microcomputers provided in the video recording / reproducing apparatus are shown. In particular, FIG. 4A illustrates the communication protocols of the SPI and MMC schemes. For common use, pull-up resistors R1, R2, R3, and R4 are connected to each of the four ports P0, P1, P2, and P3, and the ports P0 to P3 are SPI. ), SCK, SDO, SDI and CS are transmitted or received, and in the case of MMC (MMC), CLK (Clock), CMD (Command) and DAT (Data) are respectively transmitted / received. A data interface, that is, a data read operation, with a multimedia ROM card constructed and connected as described above is illustrated in FIG. 5.

FIG. 5 is a flowchart illustrating a data interface method with a multimedia ROM card. When an external key for requesting data read operation is input to the microcomputer 2, first, input / output ports P0 to FIG. P3) is set as a unidirectional SPI port (S50), and a command for resetting in an SPI mode for an interface with a connected memory card is provided. After transmitting to the controller 4 of 1), a response received from the controller 4, i.e., information about the type of the memory card 1 or a communication protocol that can be interfaced, is received and checked (S51). The connected card 1 is an MMC card which can use the SPI method according to the response result S52. Or, it is determined whether it is a multimedia ROM card capable of interfacing data only by the MMC, and the response is normally received. If it is determined that the connected card is an MMC card, and performs a data interface (S100) using the SPI method described above with reference to FIGS. 3A and 3B (S100), and if the response is not normally received, the connected card. Is a multimedia ROM card, and resets the multimedia ROM card to a MMC communication protocol capable of interfacing with the multimedia ROM card. After transmitting to the controller 4 of (1), the response received from the controller 4 is checked (S53).

Thereafter, a read block command for specifying a data read area of the multimedia ROM card, that is, the flash memory 3, which has been reset using an MMC communication protocol is transmitted. 2) After the read area command is transmitted at high speed in the SPI port state, the controller checks the response received from the controller 4 (S54), and receives a unidirectional SPI port when receiving a normal response. Set the variable to the general input / output port capable of bi-directional data transmission (S55).

Thereafter, the data line start data received through the variable set general input / output port is checked (S56), and data read from the multimedia ROM card according to the check result (S57) in block units. That is, the data is received in units of data blocks corresponding to 512 bytes (S58). Thereafter, the end bit and the file end data indicating the end of data transmission are detected (S59 and S60), and the read operation is terminated, so that any data file to be read is read by the multimedia ROM ( ROM) is read from the card (1).

Hereinafter, the operation will be described in more detail with reference to FIGS. 6 and 6B.

6A and 6B illustrate a data format according to the present invention. First, as described above, the microcomputer 2 uses a transmission scheme for data interface with a multimedia card (MMC) or a multimedia ROM (ROM) card. 6A (S), the SPI command of the format shown in FIG. 6A is transmitted to the connected card, and if the normal response is not checked by checking the R1 response, the connected card is multimedia. Recognizes as a ROM card, and transmits an MMC command having a format as shown in FIG. 6A (b). The MMC command resets an interface method with a memory card to an MMC method. It is. In the case of the MMC command, since there is no response, another command, that is, the command 2 (All_Send_CID) having a response, is continuously transmitted, and the response is checked. The length of the data read block to be read from the multimedia ROM card is obtained.

If, in the above process, the transmission method can use the SPI method, that is, when connected to the multimedia card (MMC), the data interface as described above with reference to FIG. 3B may be performed.

However, in the case of a multimedia ROM card that supports only the MMC method, the interface method must be reset to the MMC method as described above, and then the command 3 and the response are shown in (c) of FIG. 6B. ) And the response timing. On the other hand, since the format of the command 3 follows the format shown in FIG. In order to satisfy (Cycle) (2 to 64 clocks), switch the SPI dedicated port to a regular port.

In other words, if SPI mode is used, SCK, SD1, SD0, CS ports are used for one-way transmission and reception. In MC mode, SCK is used as CLK, SDI as CMD, SDO is used as DAT port, and CS is not used. By setting in advance at the time of program creation, the mode is automatically switched when the mode is determined. After switching the output port P0-SCK shown in Fig. 4A to the input port, two clocks (CLK) are generated and the port P1 To check again whether the value is a Start Bit, if the check result is not a Start Bit, repeat up to 64 clocks until the Start Bit is detected, and if the Start Bit is detected, send the value of the port P1. On the other hand, after generating one clock (CLK) with the ports P0--SCK, check the content, the CRC, the end bit (E: End Bit), and so on. Continue to generate one clock (CLK) with SCK. After the end bit (E) is detected, the check operation is completed. On the other hand, in order to read the data, the transmission protocol of the read block as shown in (d) of FIG. 6B must be satisfied. After setting the interface method to the MMC method, the host command 0x51, 0x00, 0x00, 0x00, 0x00, and 0xff are transmitted to the MMC card since 0x51 is the block 17 command.

Since the NCR cycle (2 to 64 clocks) must be satisfied, SPI dedicated ports are converted to general ports. First, switch ports P1--SCK to input ports, and generate 2 clocks with ports P0--SDO. Check that the value of port P1 is the Start Bit. If the check result is not the start bit, one clock is generated to the P0-SCK port, and the operation is repeated up to 64 clocks until the start bit is detected at the port P1. On the other hand, when the start bit is detected, the transmission value of the port P1 is checked, one clock is generated by the ports P1--SCK, and then it is checked whether the value of the port P2--SDI is the start bit, and the ports P0--SCK Generates 1 clock. Thereafter, the above operation is repeated to detect when the value of the port P2-SDI is the start bit, and when the start bit is detected, a temporary buffer (rxdata, not shown) to store read data is arbitrarily set, and serial ( Serial) After the data read in 1 bit unit is stored in the storage block 0 (rxdata 0) of the buffer in 1 byte unit, it is shifted and 8 clocks are generated by the ports P0--SCK. Repeated times, one byte of read data is stored in the buffer. Therefore, after repeating the stored 1-byte data reading and storing operations 512 times, and reading out 2 bytes again, the data of a single block unit is read.

In the case of a multimedia ROM card capable of reading data using only an MMC communication protocol, an MMC communication protocol and data transmission are performed to a conventional microcomputer equipped with an SPI port. And variablely setting the SPI port to a general input / output port capable of selectively transmitting and receiving data in both directions according to a reception state, thereby performing a data reading operation of the multimedia ROM card.

The data interface method between the microcomputer and the memory card according to the present invention configured and configured as described above is based on the type of the memory card, that is, the multimedia card or the multimedia ROM card, according to the SPI or MMC method. By selectively using the communication protocol and variablely setting the input / output port to the unidirectional SPI port for high speed data transmission or the general input / output port for bidirectional data transmission and reception according to the data transmission and reception status. It is a very useful invention that can easily implement a data interface with a plurality of memory cards that require different communication protocols, that is, a multimedia card and a multimedia ROM card, using a conventional microcomputer having an SPI port. .

Claims (3)

In the data interface method between a microcomputer and a memory card, Transmitting all confirmation commands of the microcomputer to the memory card; Step 2 of transmitting a communication mode supported by the memory card to the microcomputer: Selecting a communication protocol corresponding to the transmitted supported communication mode; and And data communication with the memory card using the selected communication protocol. 4. The method of claim 1, In step 3, a communication protocol is selected in an SPI mode or an MMC mode in response to the transmitted supported communication mode. The method of claim 1, In step 3, when the communication mode is selected as the MC mode, the data between the microcomputer and the memory card is configured to detect the communication start data from the memory card and variably set the output port to the bidirectional input / output port. Interface method.