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MMC1/SDCard: problem when MMCi_CMD line reset too soon after CMD0.

Other Parts Discussed in Thread: OMAP3503

Hello Omap experts,

I'm working on a custom board based on OMAP3503. No OS used, bare-metal environment.

I have written a driver for SDCard (plugged on MMC1 module) and I have noticed a kind of timing issue during the card initialization procedure.

After issuing CMD0, I trigger a mmci_cmd line software reset using MMCHS_SYSCTL[25].src bit.

If I trigger this reset right after the end of CMD0, the MMC module return some errors for the next command sent.

If I insert some delay between between CMD0 and the reset, the error do not occur.

When the CMD0 is sent I monitor the MMCHS_STAT.cc bit ... and it clearly indicates that the CMD0 is finished. So there should be no problem to issue the reset.

If someone have any idea??

 

Thanks!

Nicolas.