Renesas SH7781 - Manual (Page 1243)

24. Multimedia Card Interface (MMCIF)
Rev.1.00 Jan. 10, 2008 Page 1213 of 1658
REJ09B0261-0100
• The command response is received from the card.
If the card returns no command response, the command response is detected by the command
timeout error (CTERI).
• The end of the command sequence is detected by poling the BUSY flag in CSTR or by the
command response receive end interrupt (CRPI).
• Check whether the state is data busy through the DTBUSY bit in CSTR. If data busy is
detected, the end of the data busy state is then detected through the data busy end interrupt
(DBSYI).
• Write the CMDOFF bit to 1, if a CRC error (CRCERI) or a command timeout error (CTERI)
occurs.
• The MMCCMD and MMCDAT pins go to the high impedance state when the MMCIF and the
MMC card do not drive the bus and the input level of these pins is high because they are
pulled-up internally.
MMCCLK
MMCCMD
MMCDAT
CMDSTRT
(CMDSTART)
INTSTR0
(CMDI)
CSTR
(BUSY)
(CWRE)
(REQ)
(CRPI)
(DBSYI)
(DTBUSY_TU)
(DTBUSY)
Input/output pins
Command output (48 bits)
Command transmission
started
Command response
reception
(No busy state)
Command transmission period
Command sequence execution period
Response reception
completed
Figure 24.5 Example of Command Sequence for Commands without Data Transfer
(No Data Busy State)