Figure 308. Sdio "No Response" And "No Data" Operations; Figure 309. Sdio (Multiple) Block Read Operation - ST STM32F40 Series Reference Manual

Secure digital input/output interface (SDIO)
The basic transaction on the MultiMediaCard/SD/SD I/O bus is the command/response
transaction. These types of bus transaction transfer their information directly within the
command or response structure. In addition, some operations have a data token.
Data transfers to/from SD/SDIO memory cards are done in data blocks. Data transfers
to/from MMC are done data blocks or streams. Data transfers to/from the CE-ATA Devices
are done in data blocks.

Figure 308. SDIO "no response" and "no data" operations

Figure 309. SDIO (multiple) block read operation

SDIO_CMD
SDIO_D
847/1422
From host to card(s)
SDIO_CMD Command
SDIO_D
Operation (no response)
From host to card From card to host
Command Response
Data block crc
Block read operation
Multiple block read operation
Doc ID 018909 Rev 4
From host to card
Command
data from card to host
Data block crc
From card to host
Response
Operation (no data)
ai14734
Stop command
stops data transfer
Command Response
Data block crc
Data stop operation
RM0090
ai14735