This field holds the byte address of the executing command of the descriptor
table. The 32-bit address descriptor uses SDMMC_ASAR. At the start of ADMA, the user
must set the start address of the descriptor table. The ADMA increments this register
address, which points to the next Descriptor line to be fetched.
When the ADMA Error (ADMA) status flag rises, this field holds a valid descriptor address depending on the ADMA Error State (ERRST). The user must program Descriptor Table on 32-bit boundary and set 32-bit boundary address to this register. ADMA2 ignores the lower 2 bits of this register and assumes it to be 0.