Hi all,

I use AT89S52 to read data from MMC card, the card accepted and send 512 byte of sector 0 (boot sector) but all data are 0x00, only 2 last byte 55 AA.

I also use debug command for read this sector and have many data on it.

I don't know why my MCU just get 0x00 data, please give me your ideas.

I do it step by step as below

1/ send CMD0 to card --> response 0x01
2/ send CMD1 to card --> response 0x00
3/ send CMD16 to card --> response 0x00
4/ send CMD17 to card --> response 0x00
5/ wait for token 0xFE and received 512 byte data

regards,
linh.