Our company received an AM335x EVM board but it refuses to boot from any SD card.
Obviously, the board should just boot from the supplied SD cards (Linux and Android) and we can clearly see that it does load and execute the MLO file from it. The SPL then initializes the MMC, which is succesful, but after sending the READ_SINGLE_BLOCK command for the first time, all subsequent commands to the SD card hang because the SD card never becomes "ready" again. See attached MMC trace.
The board boots perfectly into Linux from UART, so the impact of the problem is limited to the MMC functionality.
After discussing the problem with TI representative, we strongly feel like this is a production problem that only occurs on the board we have (not with others).
It looks as if the MMC init speed (1bit/400 kHz) mode is working correctly, but the 4bit high-speed mode fails. Maybe one of the lanes is broken, or it's a solder issue, or maybe an issue with the TPD6E001.
Questions:
1) Can someone confirm that his AM335x EVM board is booting normally from SD card out-of-the-box ?
If that's the case, then the chances that our board has a unique manufacturing issue are very real...
I found a report of someone booting the EVM from SD card, so this question is answered.
2) Any hints, suggestions ? If this turns out to be a manufacturing issue, I think returning the EVM for a new one is the best solution...
Thanks in advance !
Tom.
