ST STM32L4+ Series Reference Manual page 1976

Secure digital input/output MultiMediaCard interface (SDMMC)
Flag
CMDSENT Set at the end of the command without response. (CPSM moves from SEND to IDLE)
Set at the end of the command response when the CRC is OK. (CPSM moves from RECEIVE to
CMDREND
IDLE)
Set at the end of the command response when the CRC is FAIL. (CPSM moves from RECEIVE to
CCRCFAIL
IDLE)
Set after the command when no response start bit received before the timeout. (CPSM moves
CTIMEOUT
from WAIT to IDLE)
Set after the voltage switch (VSWITCHEN = 1) command response when the CRC is OK and the
CKSTOP
SDMMC_CK is stopped. (no impact on CPSM)
VSWEND Set after the voltage switch (VSWITCH = 1) timeout of 5ms + 1ms. (no impact on CPSM)
CPSMACT Command transfer in progress. (CPSM not in Idle state)
The Command path error handling is shown in
Error CPSM state
Timeout Wait
CRC status Receive
1. When CMDTRANS is set, also a stop_transmission command shall be send to move the DPSM to Idle.
Data path
The data path subunit transfers data on the SDMMC_D[7:0] lines to and from cards. The
data transmit path is clocked on the SDMMC_CK and sends data to the card.The data
receive path is clocked on the sdmmc_rx_ck and receives data from the card.
shows the data path block diagram.
1976/2301
Table 393. Command path status flags
Table 394. Command path error handling
Cause Card action
No start bit in
Unknown
time
Negative
Command ignored
status
Transmission
Command accepted
error
RM0432 Rev 6
Description
Table 397:
Host action
Reset or cycle power
(1)
card
Resend command
Resend command
RM0432
CPSM action
Move to Idle
(1)
Move to Idle
(1)
Figure 578