ST STM32L4+ Series Reference Manual page 1963

RM0432
Table 382. STM32L4P5xx and STM32L4Q5xx SDMMC features (continued)
SDMMC_CDIR, SDMMC_D0DIR
SDMMC_D123DIR
1. X = supported.
54.3 SDMMC bus topology
Communication over the bus is based on command/response and data transfers.
The basic transaction on the SD/SDIO/e•MMC 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 are done in the following ways:
•
Block mode: data block(s) with block size 2
•
SDIO multibyte mode: single data block with block size range 1-512 bytes
•
e•MMC Stream mode: continuous data stream
Data transfers to/from e•MMC cards are done in data blocks or streams.
SDMMC_CMD
SDMMC_D
From host to card
From card to host
SDMMC_CMD
SDMMC_D
From host to card
From card to host
Note: The Stop Transmission command is not required at the end of a e•MMC multiple block read
with predefined block count.
Secure digital input/output MultiMediaCard interface (SDMMC)
SDMMC modes/features
Figure 568. SDMMC "no response" and "no data" operations
CMD
Operation no response and no data
Figure 569. SDMMC (multiple) block read operation
CMD Response
Data block CRC
Block read operation
Multiple block read operation
(1)
N
bytes with N in the range 0-14.
Operation response no data
Data block CRC
RM0432 Rev 6
SDMMC1
X
X
CMD Response
Data stop operation
CMD Response
Data block CRC
SDMMC2
-
-
MSv40124V1
MSv40155V1
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