STM32F42xx and STM32F43xx silicon limitations STM32F42xx and STM32F43xx
26/36 DocID023833 Rev 5
2.9.3 Data corruption in SDIO clock dephasing (NEGEDGE) mode
Description
When NEGEDGE bit is set to ‘1’, it may lead to invalid data and command response read.
Workaround
None. A configuration with the NEGEDGE bit equal to ‘1’ should not be used.
2.9.4 CE-ATA multiple write command and card busy signal management
Description
The CE-ATA card may inform the host that it is busy by driving the SDIO_D0 line low, two
cycles after the transfer of a write command (RW_MULTIPLE_REGISTER or
RW_MULTIPLE_BLOCK). When the card is in a busy state, the host must not send any
data until the BUSY signal is de-asserted (SDIO_D0 released by the card).
This condition is not respected if the data state machine leaves the IDLE state (Write
operation programmed and started, DTEN = 1, DTDIR = 0 in SDIO_DCTRL register and
TXFIFOE = 0 in SDIO_STA register).
As a consequence, the write transfer fails and the data lines are corrupted.
Workaround
After sending the write command (RW_MULTIPLE_REGISTER or
RW_MULTIPLE_BLOCK), the application must check that the card is not busy by polling the
BSY bit of the ATA status register using the FAST_IO (CMD39) command before enabling
the data state machine.
2.9.5 No underrun detection with wrong data transmission
Description
In case there is an ongoing data transfer from the SDIO host to the SD card and the
hardware flow control is disabled (bit 14 of the SDIO_CLKCR is not set), if an underrun
condition occurs, the controller may transmit a corrupted data block (with wrong data word)
without detecting the underrun condition when the clock frequencies have the following
relationship:
[3 x period(PCLK2) + 3 x period(SDIOCLK)] >= (32 / (BusWidth)) x period(SDIO_CK)
Workaround
Avoid the above-mentioned clock frequency relationship, by:
• Incrementing the APB frequency
• or decreasing the transfer bandwidth
• or reducing SDIO_CK frequency
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