CCS/AM4378: MMC boot issue

Nathan Wright

Part Number: AM4378

Tool/software: Code Composer Studio

Hello all,

I am bringing up our custom board (cloned from AM437x-gp-evm). I'm making it through the u-boot SPL stage. When u-boot proper comes up it believes there is no card inserted in to the SD slot. Is there a way via the JTAG to view the status of the R25 pin? Can I browse a register in memory viewer perhaps? Which register would it be?

Thanks,

Nathan

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

Please post the SD card slot part (and processor connections) of the schematic.

0 Nathan Wright over 8 years ago in reply to Biser Gatchev-XID

Intellectual 782 points

Hi Biser,

Turns out, u-boot was right. Our card cage was damaged and the MMC0_SDCD line was never pulled low. We helped it go low and now we're booted in to Linux.

For historical purposes: our schematic is identical to GP EVM schematic 1.4A sheet 8. The CD pin inside of SCHA5B0200 (which is actually obsolete, we replaced it with a Molex 5040771891) was damaged and was not connecting to VSS on card insertion.

Thanks,
Nathan

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CCS/AM4378: MMC boot issue