Sdio Command Register (Sdio_Cmd) - STMicroelectronics STM32F405 Reference Manual

RM0090
31.9.4

SDIO command register (SDIO_CMD)

Address offset: 0x0C
Reset value: 0x0000 0000
The SDIO_CMD register contains the command index and command type bits. The
command index is sent to a card as part of a command message. The command type bits
control the command path state machine (CPSM).
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
Bits 31:15 Reserved, must be kept at reset value
Bit 14 ATACMD: CE-ATA command
Bit 13 nIEN: not Interrupt Enable
Bit 12 ENCMDcompl: Enable CMD completion
Bit 11 SDIOSuspend: SD I/O suspend command
Bit 10 CPSMEN: Command path state machine (CPSM) Enable bit
Bit 9 WAITPEND: CPSM Waits for ends of data transfer (CmdPend internal signal).
If this bit is set, the CPSM waits for the end of data transfer before it starts sending a
command.
Bit 8 WAITINT: CPSM waits for interrupt request
Bits 7:6 WAITRESP: Wait for response bits
Bits 5:0 CMDINDEX: Command index
The command index is sent to the card as part of a command message.
Note: After a data write, data cannot be written to this register for three SDIOCLK (48 MHz) clock
periods plus two PCLK2 clock periods.
MultiMediaCards can send two kinds of response: short responses, 48 bits long, or long
responses,136 bits long. SD card and SD I/O card can send only short responses, the
Reserved
If ATACMD is set, the CPSM transfers CMD61.
if this bit is 0, interrupts in the CE-ATA device are enabled.
If this bit is set, the command completion signal is enabled.
If this bit is set, the command to be sent is a suspend command (to be used only with SDIO
card).
If this bit is set, the CPSM is enabled.
If this bit is set, the CPSM disables command timeout and waits for an interrupt request.
They are used to configure whether the CPSM is to wait for a response, and if yes, which
kind of response.
00: No response, expect CMDSENT flag
01: Short response, expect CMDREND or CCRCFAIL flag
10: No response, expect CMDSENT flag
11: Long response, expect CMDREND or CCRCFAIL flag
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