ST STM32F101xx User Manual

Secure digital input/output interface (SDIO) RM0008
586/1096 Doc ID 13902 Rev 12
22.9.4 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).
Note: 1 At least seven HCLK clock periods are needed between two write accesses to this register.
2 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
313029282726252423222120191817161514131211109876543210
Reserved
CE-ATACMD
nIEN
ENCMDcompl
SDIOSuspend
CPSMEN
WAITPEND
WAITINT
WAITRESP
CMDINDEX
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:15 Reserved, always read as 0.
Bit 14 ATACMD: CE-ATA command
If ATACMD is set, the CPSM transfers CMD61.
Bit 13 nIEN: not Interrupt Enable
if this bit is 0, interrupts in the CE-ATA device are enabled.
Bit 12 ENCMDcompl: Enable CMD completion
If this bit is set, the command completion signal is enabled.
Bit 11 SDIOSuspend: SD I/O suspend command
If this bit is set, the command to be sent is a suspend command (to be used only with SDIO
card).
Bit 10 CPSMEN: Command path state machine (CPSM) Enable bit
If this bit is set, the CPSM is enabled.
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
If this bit is set, the CPSM disables command timeout and waits for an interrupt request.
Bits 7:6 WAITRESP: Wait for response bits
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
Bit 5:0 CMDINDEX: Command index
The command index is sent to the card as part of a command message.

ST STM32F101xx Specifications

General

Brand	ST
Model	STM32F101xx
Category	Microcontrollers
Language	English