Setting up SDIO interface on F4 -CMD2 issues

jdcowpland · ‎2013-10-10

Posted on October 10, 2013 at 16:24

Hi guys,

I'm currently setting up an SD Card on the STM32F4 Discovery and have managed to so far get through the initial setup commands without too many issues. CMD0, CMD8,CMD55,CMD41 have all successfully been sent and the responses I've got back have been what I've been expecting. I'm now at the stage where I'm sending CMD2 though and I'm picking up a CTIMEOUTC flag in the status register with no response detected on the line. Been looking everywhere to try and find out why I might not be getting a response but can't find anything. Anybody got any ideas or insights?

Cheers!

#sdio

jdcowpland · ‎2013-10-29

Posted on October 29, 2013 at 16:18

Managed to solve this after realising I needed to send ACMD41 twice before sending CMD2. Now have another issue though. Managed to get everything working perfectly with a standard 1GB SD card. Initialisation all works and I have set up FAT16 on it. Now trying it on a microSD card though, and it's always returning the busy flag in the OCR register when I send it a ACMD41. Anyone know why this might be? I've got a timeout which counts down from 0xFFFF and it reaches the time out every single time.