KR20010063803A - Multimedia Card(MMC) To Support The Video Codec Function - Google Patents

Abstract

PURPOSE: The MMC(Multimedia Card) supporting the video codec function is provided to support the video codec function in a small terminal while adapting the interface of the smallest MMC CONSTITUTION: The MMC has a REG_FILE(Registry File)(1), which controls the state and processing of a card, and a registry is accessed by an MMC host. An IF_DRIVER(Interface Driver)(2) drives three signals like CMD(RSP), CLK, and DAT that are inputted by a MMC_IF(Multimedia Card Interface)(3). The MMC_IF recognizes and processes each command, put together the response processing, controls the data send/receive, and provides the mean for accessing to the registry information. A V_CODEC_IF(Video Codec Interface)(4) controls the exchange of the control signal and the data send/receive between the MMC_IF and a V_CODEC(Video Codec)(6). The V_CODEC processes the video compression and recovery algorithm. A FIFO(First In First Out)(5), temporary storage when the data between the V_CODEC and MMC host is exchanged, buffers the data. The REG_FILE is a gathering of registries, which include the control information for the normal operation and whole state of the MMC.

Description

Multimedia Card (MMC) To Support The Video Codec Function}

The present invention relates to a multimedia card that supports the video codec function.

With the development of high density integrated circuits (VLSI) and computing technology, various types of small size terminals have been released in accordance with the trend of miniaturization of all products (terminals refer to PDA and HPC).

However, due to the small size of the terminal, the interface system that can be connected to the terminal is also becoming smaller. In accordance with this trend, various types of small cards have been developed, and the present invention seeks to implement video codec functions on a specific card, which is one of such cards, a multimedia card (MMC) (hereinafter simply referred to as "MMC").

First, a quick look at MMC: In May 1997, SIEMANS and SanDisk companies began developing a new data storage medium called MMC. The MMC can be easily applied to a data storage medium, a high capacity, a portable terminal, which is as small as a postage stamp, and has the characteristics of an efficient battery usage and a cheap and simple interface for the portable terminal.

Until now, there are no technologies that implement the MMC-based video codec function, but there are only methods that support the video codec function through another PC-based interface and directly mount it on the system board.

That is, the conventional means for providing a video telephone function has a variety of forms depending on the use environment. These methods are mainly in the form of a single card (PCB circuit) that is mounted in a conventional PC-based or telephone terminal and provides a function, and methods that are directly mounted in a system board.

However, there is a problem that these methods cannot be used under the current situation in which the terminal to be miniaturized must be externally supported as an option. Therefore, it is inevitable to change to a small that can be mounted in the external slot provided by the small terminal. In this case, there is a difference depending on which interface the terminal provides.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and at the time of increasing number of terminals providing the multimedia card type interface, which is the smallest card, the present invention provides a multimedia card supporting the video codec function at the same time. The purpose is.

1 is a configuration diagram of an embodiment of a multimedia card that supports a video codec function according to the present invention.

Figure 2 is a detailed block diagram of one embodiment of the multimedia card interface (MMC_IF) in the multimedia card according to the present invention.

FIG. 3 is a detailed configuration diagram of an embodiment of the command response unit CMD_RSP in the multimedia card interface MMC_IF according to the present invention.

4 is a detailed configuration diagram of an embodiment of a multimedia card control unit MMC_CTRL in the multimedia card interface MMC_IF according to the present invention.

5 is a detailed configuration diagram of an embodiment of the validity check unit C_CRC in the multimedia card interface MMC_IF according to the present invention.

Explanation of symbols on the main parts of the drawings

1: register file 2: interface driver

3: multimedia interface 4: video codec interface

5: FIFO 6: Video Codec

According to an aspect of the present invention, there is provided a multimedia card supporting a video codec function, comprising: interface driving means for exchanging information with an external multimedia card host; Multimedia interfacing means for receiving and processing various commands provided by the host from the interface driving means and transmitting the result to the driving means; Video signal processing means for performing a video codec function to compress and decompress the video signal; And video signal interfacing means for storing various data processed by the video signal processing means and sequentially transmitting the data to the multimedia interfacing means.

In order to implement the video codec function through the MMC card interface, the card itself must provide a means for recognizing and processing various MMC-related commands, and through this interface, data exchange with the video codec module and related control means. Must be equipped.

In more detail, the host (terminal) adopting the MMC card interface outputs various commands for accessing the MMC card, and it is necessary to provide a control and data exchange means for recognizing these commands and processing the commands. The video codec interface must be equipped to exchange data received through this interface with the video codec module. In conclusion, it must recognize all MMC commands and support all mechanisms for the card to operate under host control.

The functions that an MMC card must provide are classified as follows. First, it must be able to recognize various commands emitted from the MMC host. Second, the correct response to the recognized command must be given. Third, normal transmission / reception must be guaranteed when exchanging data between the card and the host. Fourth, the CRC check function and generation function for the bitstream should be inserted in the first command recognition and response. Fifth, the correct operation mode switching process of the card according to the command recognition should occur. Sixth, high speed data transmission / reception with the video codec module should be made. Seventh, correct data CRC check and generation are required when exchanging data with card host. The structure for satisfying all these functions is the content of this patent.

That is, in order to perform a video codec related function in a small terminal, a separate external interface means is required, and these interfaces are also very small to fit the small terminal. Accordingly, the present invention provides a video codec function in a small terminal by providing a means for implementing a video codec related function in hardware through an MMC interface, which is one of such card interfaces. Suggest.

Hereinafter, a preferred embodiment of the present invention will be described in detail.

1 is a configuration diagram of a multimedia card that supports a video codec function according to an embodiment of the present invention, and is an overall card structure for providing a video codec function through an MMC interface method.

For data exchange and control between the video codec (V_CODEC) (hereinafter simply referred to as "V_CODEC") 6 and the MMC host, reception and interpretation of the MMC signal, status control of the MMC card, data transmission and related control means are provided. In addition, various control registers and status information registers are required for MMC internal control.

The interface driver IF_DRIVER (hereinafter simply referred to as "IF_DRIVER") 2 in which the card is directly interfaced to the MMC host drives three signals, CMD (RSP), CLK, and DAT signals. These signals are input to the multimedia card interface MMC_IF (hereinafter simply referred to as "MMC_IF") 3.

The MMC_IF 3 recognizes and processes various commands provided by the host, manages the corresponding response processing, and controls data reception and transmission. It also provides a means for accessing various register information.

The part that controls the control signal exchange and data transmission and reception between the MMC_IF 3 and the V_CODEC 6 is the video codec interface V_CODEC_IF (hereinafter simply referred to as "V_CODEC_IF") 4. The module generates control signals for sending and receiving data and first-in-first-out (FIFO) access via V_CODEC (6) and DMA transfer cycles. At this time, the data to be transmitted is stored in a first in first out (FIFO) (hereinafter simply referred to as "FIFO") 5, and data movement is performed according to a card access type, that is, a read or write operation.

V_CODEC (6) handles the video compression and decompression algorithm. At this time, necessary data or processed data are first stored in the FIFO 5 through V_CODEC_IF (4) and sequentially exchanged with the MMC host through MMC_IF (3). The MMC card has register files REG_FILE (hereinafter simply referred to as "REG_FILE") 1 for controlling the status and processing of the card, and these registers are accessed by the MMC host.

V_CODEC_IF (4) is responsible for the transfer of various data between the V_CODEC (6) and the multimedia card control unit (MMC_CTRL) (hereinafter referred to simply as "MMC_CTRL") (9), the transfer is made through the DMA procedure, necessary data Stored in a first-in first-out (FIFO) 11, it provides a means for generating various control signals for DMA and control signals for FIFO access.

The V_CODEC (6) performs an H.263 function and receives image frame data for compression and a bitstream for reconstruction from the MMC host. It also outputs the compressed code. This data movement is made with the MMC host through the interface of the MMC card.

The FIFOs 11 and 5 buffer the data to temporary storage when data is exchanged between the V_CODEC and the MMC host. Finally, REG_FILE (1) is a register that contains the overall status of the MMC card and various control information for normal operation of the MMC card.

FIG. 2 is a detailed configuration diagram of an embodiment of a multimedia card interface (MMC_IF) in a multimedia card according to the present invention. FIG. 3 is a detailed diagram of a command response unit (CMD_RSP) in a multimedia card interface (MMC_IF) according to the present invention. It is a block diagram.

As shown in the figure, MMC_IF (3) is composed of CMD_RSP (7), C_CRC (8), MMC_CTRL (9), D_PATH (10), FIFO (11), D_CRC (12).

The command response unit CMD_RSP (hereinafter, simply referred to as “CMD_RSP”) 7 is a latch of various commands provided by the MMC host and a movement of response signals to commands, and supports data movement for supporting input processing of input commands. A control section (Dir Ctrl) 13 and a shift register section (Shift reg) 16 are included.

The data movement control unit (Dir Ctrl) (hereinafter simply referred to as "Dir Ctrl") 13 controls the data movement by performing direction control of the command input and the response bitstream output.

The shift register section (hereinafter, simply referred to as "Shift reg") 16 performs a bit shift operation for eight clocks upon command input.

The token generating unit TOKEN_GEN (hereinafter, simply referred to as “TOKEN_GEN”) 17 receives data of the shift reg 16 and performs detection of “01”, and then outputs a token generating signal.

The delay command unit DLY_CMD (hereinafter, simply referred to as "DLY_CMD") 15 performs a three clock delay of shifted data to synchronize.

The output signal of the CMD_RSP 7 is interfaced with the validity check unit C_CRC (hereinafter simply referred to as "C_CRC") 8 and the MMC_CTRL 9.

An access determining unit (Card bus wins) (hereinafter simply referred to as "Card bus wins") 14 compares the value exported by this card with the value displayed on the actual CMD line to determine whether the current card is being accessed. Several signals for command decoding are generated in the CMD_RSP block and input to the MMC_CTRL unit.

In conclusion, it is classified into command number, argument information and end bit signal for command recognition as input / output paths of command and response bitstreams and input into MMC_CTRL (9), and data is input into C_CRC (8) to check the validity of commands. It is used as the output path of the response bitstream. At this time, the output of C_CRC (8) is received as an input and connected to the CMD line.

4 is a detailed configuration diagram of an embodiment of the multimedia card control unit MMC_CTRL 9 in the multimedia card interface MMC_IF according to the present invention.

MMC_CTRL (9) is a general control for the operation of the MMC card, command latch, recognition, decoding through the MMC interface, command argument information latch, determination of the response type according to the command, output after generating the response bit stream, It provides various control means related to the state maintenance and transition of the MMC card and data transfer.

The command latching unit (CMD_REG) (hereinafter simply referred to as "CMD_REG") 18 latches the input command and uses the currently latched command as a valid command when it is determined to be a CRC_OK and a valid command in C_CRC 8. . All processing related to this command is started while latching as a valid command.

Argument storage unit ARG_LATCH (hereinafter simply referred to as "ARG_LATCH") means 20 stores information carried with the command and starts storing and processing this argument when it is confirmed as a valid command. This value is moved to the external REG_FILE (1) via the argument storage control unit ARG_LATCH_CTRL (hereinafter simply referred to as "ARG_LATCH_CTRL") 24.

The end detector END_DETECT (hereinafter simply referred to as "END_DETECT") 21 provides a means for detecting a signal indicating the end of the command. The detection of this bit identifies the valid command again.

The card selector CARD_SEL (hereinafter, simply referred to as “CARD_SEL”) 22 receives information indicating that the current card is being selected among several MMC cards and a signal generated in the Card Bus Wins 14 of FIG. 3. In this case, the MMC is given a unique number during the card recognition process and detects that the number matches the argument field information from the command.

The state control unit MMC_CTRL_STATE_MACHINE (hereinafter simply referred to as "MMC_CTRL_STATE_MACHINE") 25 is composed of a state machine for recognizing an MMC card and a state machine related to data transfer of the MMC card. These state machines require a valid command and various valid signals to be entered to cause a state transition of the internal state machine. Otherwise, the current state will be maintained. These machines oversee the overall control of the card.

The validity check control unit CRC_CTRL (hereinafter, simply referred to as "CRC_CTRL") 23 checks that the command currently latched is not valid due to the generation of the start signal of the C_CRC (8) unit for checking the validity of the command and the occurrence of an error in the C_CRC unit. do. In addition, if the CRC generation and CRC operation for the response bitstream is not required, the bitstream is bypassed. In addition, the D_CRC 12 is controlled for validity and accuracy of the interchanged data.

The argument latch control unit ARG_LATCH_CTRL (hereinafter, simply referred to as "ARG_LATCH_CTRL") 24 generates operation signals for storing the argument information on command with the command and reading the state information value of the register.

The register controller RES_CTRL (hereinafter simply referred to as "RES_CTRL") 28 generates corresponding response bitstream information according to the command type and outputs the corresponding bitstream information to the C_CRC unit.

Whether the current card is capable of operating at the power level provided by the MMC host is made at the power check unit (VDD_CHECK) (hereinafter simply referred to as "VDD_CHECK") 27 and used as a condition for the state transition of the MMC_CTRL_STATE_MACHINE 25. .

The command decoding unit CMD_DEC (hereinafter, simply referred to as “CMD_DEC”) 19 decodes an input valid command and inputs the signals to MMC_CTRL_STATE_MACHINE 25, CRC_CTRL 23, and ILL_CMD 26 to control signals. to provide.

The non-compliant command check unit (ILL_CMD) (hereinafter simply referred to as "ILL_CMD") 26 is a means of checking when an invalid command is input in any state of the card and this value is written to the status register of REG_FILE (1). do.

The data movement signal control unit D_PATH_CTRL (hereinafter, simply referred to as "D_PATH_CTRL") 31 is for controlling the data movement unit D_PATH (hereinafter, simply referred to as "D_PATH") 10 according to a command and related to data movement. Generate and supply a signal.

At this time, the D_PATH 10 of FIG. 2 is a place where data (DAT) movement between the MMC host and the card is controlled in connection with the D_PATH_CTRL 31 of the MMC_CTRL 9, and the D_CRC 12 is a CRC of an input block bitstream. Performs CRC generation of the check and output block bitstreams.

The D_CRC 12 receives a control signal of the CRC_CTRL 23 of the MMC_CTRL 9. Data of the D_CRC 23 is connected to the IF_DRIVER (2).

5 is a detailed block diagram of an embodiment of the validity check unit C_CRC in the multimedia card interface MMC_IF according to the present invention.

The C_CRC 8 receives the CRC-related control signal from the CRC_CTRL 23 to perform the CRC checker function of the command and the CRC generation function of the response bitstream, and immediately bypasses the CRC operation if the CRC operation is not necessary. 30). This is used as a means to ensure the correct command through the MMC interface and the response bitstream according to the command.

That is, the video codec module is interfaced with the MMC through the structure of FIGS. 1 to 5 to implement the video codec function in the small terminal.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains, and the above-described embodiments and accompanying It is not limited to the drawing.

As described above, the present invention provides a multimedia card that supports a video codec function for adopting this interface and at the same time supporting a video codec function at an increasing number of terminals providing an interface in the form of a multimedia card, which is the smallest card. By doing so, there is an excellent effect that even a small terminal can provide a video codec function.

In addition, the present invention includes a 7-pin drive circuit through the MMC interface, and the functions for controlling the normal operation of the MMC and data exchange and control with the video codec, so that any host that provides the MMC interface It is also possible to connect, and on this basis, there is an excellent effect of using video telephony through the video codec function.

Claims (4)

In the multimedia card that supports the video codec function, Interface driving means for exchanging information with an external multimedia card host; Multimedia interfacing means for receiving and processing various commands provided by the host from the interface driving means and transmitting the result to the driving means; Video signal processing means for performing a video codec function to compress and decompress the video signal; And Video signal interfacing means for storing various data processed by the video signal processing means and sequentially transmitting the data to the multimedia interfacing means. Multimedia card that supports the video codec function, including. The method of claim 1, The multimedia interfacing means, Command response means for exchanging various commands provided by the host and the result with the interface driving means; Validity checking means for checking validity of the command; Multimedia card control means for performing a task on the command; And Data transfer means for receiving various data processed by the video signal processing means under the control of the multimedia card control means from the video signal interfacing means. Multimedia card that supports the video codec function, including. The method of claim 2, The command response means, Data movement control means for controlling data movement according to various commands provided by the host; Shifting means for performing a bit shift operation on the command input; Delay means for performing a delay on the data shifted by the shifting means and synchronizing it with the validity checking means; And Token generating means for receiving data from the shifting means and outputting a token generating signal to the multimedia card control means; Multimedia card that supports the video codec function, including. The method of claim 2 or 3, The multimedia card control means, Command latching means for latching the command until the command is determined to be a valid command; Validity checking control means for controlling said validity checking means to check validity with respect to said command; And State control means for controlling a process of performing a corresponding operation on the command whose validity is determined by the validity checking means Multimedia card that supports the video codec function, including.