Hi, I'm going to be going through the same thing in about a week's time. I'm putting together the schematic now for a data logger. For my reference I am using the Multimedia Card Product Manual from Sandisk. It is on there website. It appears to be quite comprehensive. Gordon Williams Ottawa, Canada ----- Original Message ----- From: "#LEE CHUN YONG#" To: Sent: Friday, January 16, 2004 7:26 AM Subject: [OT:] Help MMC SPI Mode Currently I am using the MMC card in SPI mode. I would like to know more about the command, write and response sequence of the writing of 1 block of data. The block size of 512 byte is used. So I will start the writing process with write block command(CMD24). After that I will try to get the response from the MMC card( I did get bit string of '0000 0000'). After that I would output 10 clocks to MMC card. Then I will start to output start byte( bit string of '1111 1110' ). Subsequently, I will write 512 bytes of data. Then I just write 2 bytes of dummy byte as the CRC. Since I didn't turn on the CRC feature of the MMC card, any 2 bytes of dummy data will be fine. After sending the 2 bytes of CRC, I should immediately get bit string of 'xxx0 0101' as the data response. Are my procedures correct? Thank you in advance and have a nice day! -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu