Commands With Write Data - Renesas H8S/2158 User Manual

19.6.3

Commands with Write Data

Commands with write data confirm the MMC status by the command responses, and then transmit
MMC information and flash memory data. For a command that is related to time-consuming
processing such as flash memory write, the MMC indicates the data busy state.
The number of bytes of flash memory to be written is a block size specified by CMD16.
When block size > transmit data FIFO size, the command sequence is suspended by FIFO empty.
When the command sequence is suspended, the next data is written to the transmit data FIFO, and
the command sequence is then continued.
Figures 19.23 and 19.24 show examples of the command sequence for commands with write data.
Figure 19.25 shows the operational flow for commands with write data.
• Settings needed to issue a command are made. Write data is set to the transmit data FIFO.
• The START bit in CMDSTRT is set to 1 to start command transmission. The CS signal goes
low (select). Command transmission complete can be confirmed by the command transmission
end interrupt (CMDI).
• A command response is received from the MMC. If the MMC does not return the command
response, the command response is detected by the command timeout error (CTERI).
• The DATAEN bit in OPCR is set to 1 to start write data transmission.
• Suspension according to the transmit data FIFO empty is detected by the FIFO empty interrupt
(FEI). Data is written to the transmit data FIFO, and the DATAEN bit in OPCR is set to 1.
• The end of the command sequence is detected by poling the BUSY flag in CSTR or the data
transfer end interrupt (DTI). Reception of data response can be confirmed by the data response
end interrupt (DPRI).
• When the command sequence ends, the CS signal goes high (not select). The end of the data
busy state is detected by poling the DTBUSY flag in CSTR or by the data busy end interrupt
(DBSYI).
Section 19 Multimedia Card Interface (MCIF)
Rev. 3.00 Jan 25, 2006 page 683 of 872
REJ09B0286-0300