I have a custom board with ATSAMA5D27 and an eMMC card. I'm trying to initialize the SDMMC peripheral to use the card, so far unsuccessfully. Could you, please, recommend me some good reading on that?
I am 100% sure that the hardware design is correct and that the card works, because SAM-BA can access the card.
Atmel doesn't provide any useful documentation on that, just some incompatible libraries, and trying to follow what happens there is more like guessing than a solid work.