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19.6.2
Commands with Read Data
Commands with read data confirm the MMC status by the command responses, and then receive
MMC information and flash memory data.
The number of bytes of flash memory to be read is a block size specified by CMD16.
When block size > receive data FIFO size, the command sequence is suspended by FIFO full.
When the command sequence is suspended, data in the receive data FIFO is processed, and the
command sequence is then continued.
Figures 19.20 and 19.21 show examples of the command sequence for commands with read data.
Figure 19.22 shows the operational flow for commands with read data.
• Settings needed to issue a command are made.
• 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).
• The 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).
• Read data is received from the MMC.
• Command abortion is detected according to the receive data FIFO full by the FIFO full
interrupt (FFI). To continue the command sequence, the RD_CONTI bit in OCR should be set
to 1.
• When the command sequence ends, the CS signal goes high (not select). The end of the
command sequence is detected by poling the BUSY flag in CSTR or by the data transfer end
interrupt (DTI).
Section 19 Multimedia Card Interface (MCIF)
Rev. 3.00 Jan 25, 2006 page 679 of 872
REJ09B0286-0300
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