R01UH0823EJ0100 Rev.1.00 Page 1454 of 1823
Jul 31, 2019
RX23W Group 40. SD Host Interface (SDHIa)
40.3.6.3 Single Block Read Command (CMD17)
Figure 40.10 shows an example of issuing the single block read command (CMD17).
1. Set the flags in registers SDSTS1 and SDSTS2 to 0.
2. Set the SDHI clock in the SDCLKCR register, and set the interrupt requests to be masked in registers SDIMSK1
and SDIMSK2. Refer to
section 40.5.5 for details on setting the SDCLKCR register.
3. After setting the argument field value for CMD17 to the SDARG register, write 0000 0011h to the SDCMD
register. The SDHI issues CMD17 when a value is written to the SDCMD register.
4. When the response is received, the SDSTS1.RSPEND flag becomes 1, and a response end interrupt request is
generated.
5. Set the SDSTS1.RSPEND flag to 0, and read the response stored in the SDRSP10 register. If the response read is in
error, set the SDSTOP.STP bit or SDIOMD.IOABT bit to 1, and the command sequence can be stopped. When the
command sequence is stopped, the SDSTS1.ACEND flag becomes 1. Note that CMD12 and CMD52 are not
automatically issued by stopping this command sequence.
6. After the response is received, set the SDIMSK1.ACENDM bit to 0 and set the SDIMSK2.BREM bit to 0.
7. After the amount of data set in the SDSIZE.LEN[9:0] bits is received from the SD card, the SDSTS2.BRE flag
becomes 1, and the BRE interrupt request is generated.
8. Set the SDSTS2.BRE flag to 0, and read the amount of data set in the SDSIZE.LEN[9:0] bits from the SDBUFR
register.
9. After data has been read from the SDBUFR register, the SDSTS1.ACEND flag becomes 1, and the access end
interrupt request is generated.
10. Set the SDSTS1.ACEND flag to 0.
Perform error processing (clear the interrupt flag) if a communication error or timeout occurs.
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