ST STM32F102 series User Manual

RM0008 SDIO interface (SDIO)
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19.9.4 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 After a data write, data cannot be written to this register for seven HCLK clock periods.
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
argument can vary according to the type of response: the software will distinguish the type
of response according to the sent command. CE-ATA devices send only short responses.
313029282726252423222120191817161514131211109876543210
Reserved
CE-ATACMD
nIEN
ENCMDcompl
SDIOSuspend
CPSMEN
WAITPEND
WAITINT
WAITRESP
CMDINDEX
r r/w r/w r/w r/w r/w r/w r/w r/w r/w
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 STM32F102 series Specifications

General

Brand	ST
Model	STM32F102 series
Category	Microcontrollers
Language	English