SD Mode Reads/Writes

[mwgilson]

I am not sure to what detail the members of this forum are aware of in regards to SD Cards, but I'm going to make this post regardless and see if anyone out there can answer it.

I am writing an SD Mode (not SPI Mode) core that reads and writes to an SD Card. I completed the initialization of the card, and I believe I can read from the card in 4-bit mode, but I am having a problem when writing to the card in 4-bit mode. When I write a 512 byte block of data (initiated by a CMD25 command), I tri-state the data bus, and see a command come back from the card. This command, from what I can tell from the Simplified Spec, is what is called a "CRC Status" byte. The Simplified Spec doesn't say what this is, except a start bit, several status bits, and an end bit. Simply put, my writes are not working, and I'd like to be able to interpret what this command is to find out why. If anyone out there could provide even the slightest assistance I would be greatful. Thank you.

[leon_squall]

I am not sure to what detail the members of this forum are aware of in regards to SD Cards, but I'm going to make this post regardless and see if anyone out there can answer it.

I am writing an SD Mode (not SPI Mode) core that reads and writes to an SD Card. I completed the initialization of the card, and I believe I can read from the card in 4-bit mode, but I am having a problem when writing to the card in 4-bit mode. When I write a 512 byte block of data (initiated by a CMD25 command), I tri-state the data bus, and see a command come back from the card. This command, from what I can tell from the Simplified Spec, is what is called a "CRC Status" byte. The Simplified Spec doesn't say what this is, except a start bit, several status bits, and an end bit. Simply put, my writes are not working, and I'd like to be able to interpret what this command is to find out why. If anyone out there could provide even the slightest assistance I would be greatful. Thank you.

Hi! I 'm Leon, a new-comer, I 've seen your post about SD cards read/write, so I decide to reply your post for accquiring some source code used for my project. Actually, I 've been researching about this and met some problems of implementing SD card based on SD Mode. If you agree on my suggestion, then send file to me through email-address: leon_squall_wknight@yahoo.com . Thanks a lot!
Leon Squall

[ranjin]

Hi I'm new to SD card,

Can you explain me how to send the commands in SD mode to the card.

It will be very usefull, if you mail the code snippet to my email ID dranjin@gmail.com


Thanks in advance,
Ranjin