Github: https://github.com/ultraembedded/core_mmc

Work-in-progress - basically functional but not yet complete / robust.

• 1-bit / 4-bit data modes.
• Large sector buffer (for multiple sector reads or writes).
• AXI-4 DMA.

• DMA: Does not support card write mode (functions as read from card only).
• Robustness: Not currently checking CRC7 / CRC16 on incoming responses.
• Writes: Multi-sector write support is not correct.
• AXI: Dubious combinatorial paths on AWVALID and WVALID.

Exercised on the following FPGA boards;

• Digilent Arty A7 (Xilinx Artix 7)
• LambaConcept ECPIX-5 (Lattice ECP5)