2021-12-25 03:06 AM
Hi.
I use a STM32F207VCT6 custom board, and i'm sure the connections are corrrect.
in 1 bit mode everythings is OK and i can read and write on micro sd.
but in 4 bit mode micro sd will mount but other functions won't work! its a little bit weird!!
i increased the sdio clock prescaler to 4... but same result...
2021-12-25 06:18 AM
Very sensitive to signal skewing, cross-talk, line-lengths, stubs and termination.
The EVAL series boards have viable schematics.
2021-12-25 06:21 AM