Card is hooked up with:
Pin 1 - DAT2 - floating
Pin 2 - DAT3 - floating
Pin 3 - CMD - SDIO_CMD to micro
Pin 4 - VDD - 3V3
Pin 5 - CLK - SDIO_CLK to micro
Pin 6 - VSS - GND
Pin 7 - DAT0 - SDIO_D0 to micro, (tried 10k pullup to 3V3 but didn't make any difference)
Pin 8 - DAT1/nIRQ - floating
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Add external pullup on CMD and other floating DATA bus Line too.
SD/MMC specification doesn't allow bus floating.
As I said in other thread, don't trust internal pullup.
aaaaagggggghhhhhhhhhhh!! I'd tried pullups on some of the lines but not all and had read on many sites that they weren't needed. Looks like they are... I've just written my first file on this board!! Shame about the wasted 3 days... grrrr
thanks for you help.
I think the F1 is more problematic with internal pull ups than the F4. My own boards have pull ups externally close to the card socket, but have used other where the internals were sufficient but the traces were very short.