pub const CMD8_MMC: Command;Expand description
CMD8 (MMC): SEND_EXT_CSD — read the 512-byte extended CSD register.
Important: this is a different CMD8 than the SD SEND_IF_COND.
MMC CMD8 carries a data phase (R1 followed by a 512-byte read),
while SD CMD8 has no data and uses R7. The protocol layer picks the
right one based on the card kind.