ST STM32F102 series

SDIO interface (SDIO) RM0008
418/690
Command path
The command path unit sends commands to and receives responses from the cards.
Figure 184. SDIO adapter command path
● Command path state machine (CPSM)
– When the command register is written to and the enable bit is set, command
transfer starts. When the command has been sent, the command path state
machine (CPSM) sets the status flags and enters the Idle state if a response is not
required. If a response is required, it waits for the response (see Figure 185 on
page 419). When the response is received, the received CRC code and the
internally generated code are compared, and the appropriate status flags are set.
ai14805
CMD
Status
flag
Control
logic
Command
timer
CRC
Argument
Shift
register
CMD
Response
registers
To control unit
SDIO_CMDin
SDIO_CMDout
To AHB interface
Adapter registers