Secure digital input/output interface (SDIO)
RM0090
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DocID018909 Rev 11
Note:
While the SD/SDIO card or MultiMediaCard is in identification mode, the SDIO_CK
frequency must be less than 400 kHz.
The clock frequency can be changed to the maximum card bus frequency when relative
card addresses are assigned to all cards.
After a data write, data cannot be written to this register for three SDIOCLK (48 MHz) clock
periods plus two PCLK2 clock periods. SDIO_CK can also be stopped during the read wait
interval for SD I/O cards: in this case the SDIO_CLKCR register does not control SDIO_CK.
31.9.3
SDIO argument register (SDIO_ARG)
Address offset: 0x08
Reset value: 0x0000 0000
The SDIO_ARG register contains a 32-bit command argument, which is sent to a card as
part of a command message.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
CMDARG
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:0
CMDARG:
Command argument
Command argument sent to a card as part of a command message. If a command contains
an argument, it must be loaded into this register before writing a command to the command
register.