SH7721 datasheet(1120/1524 Pages) RENESAS

1120 / 1524 page

Section 31

MultiMediaCard Interface (MMCIF)

Rev. 3.00 Jan. 18, 2008 Page 1058 of 1458

REJ09B0033-0300

31.4

Operation

The MultiMediaCard is an external storage media that can be easily disconnected. The MMCIF

controls data transfer with the MultiMediaCard, and operates in MMC mode.

Insert the MMC and turn on the power supply. Then operate the MMCIF by applying transfer

clocks after setting an appropriate transfer clock frequency. The MMC_VDDON signal and

MMC_ODMOD signal can be used for MMC power control and open drain mode control,

respectively.

The series of operations from command sending, command response reception, data

transmission/reception, and data response reception is called the command sequence. The

command sequence starts from sending a command by setting the START bit in CMDSTRT to 1,

and ends when all necessary data transmission/reception and response reception has been

completed. The MMC supports the data busy state in which only specific command is accepted to

program/erase the flash memory in the MMC during command sequence execution and after

command sequence execution has ended. The data busy state is indicated by a 0 output from the

MMC side to the DAT pin in MMC mode.

Note:

Do not connect or disconnect the MMC during command sequence or data busy.

31.4.1

Operations in MMC Mode

MMC mode is an operating mode in which the transfer clock is output from the MMC_CLK pin,

command transmission/response receive occurs via the MMC_CMD pin, and data is

transmitted/received via the MMC_DAT pin. In this mode the next command can be issued while

data is being transmitted/received. This feature is applied to the multiblock transfer and stream

transfer. In this case, the next command is the CMD12 command, which aborts the current

command sequence.

In MMC mode, a broadcast command that simultaneously issues a command to multiple MMCs is

supported. After the information for the MMC that is inserted by using the broadcast command is

acknowledged, a relative address is given to each MMC. One MMC is selected by the relative

address, other MMCs are deselected, and various commands are issued to the selected MMC.

Commands in MMC mode is basically classified into three types: broadcast, relative address, and

flash memory operation commands. The MMC is operated by issuing a command according to

card status.

SH7721 Datasheet(PDF) 1120 Page - Renesas Technology Corp