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Using SDMMC with STM32L476 in 1-bit mode

Question asked by Fabian Frei on Nov 15, 2017
Latest reply on Nov 27, 2017 by piet t

Hi there,


I'm trying to get the SD 1-bit  interface working on my STM32L476. I generated the code with the STM32CudeMX.


So that's my problem:
The init function "MX_SDMMC1_SD_Init" [1] stucks in a loop. So, I used the debugger to find where exactly the error occurs. You can see the code snippets below. function[1] calls function[2] , function[2] calls function[3] and so on.
In function [4], the call of SDMMC_CmdAppOperCommand(..)  generates the error "SDMMC_ERROR_CMD_CRC_FAIL". 


Any suggestions on how to solve or debug this issue any further?I have a digital analyzer, but it does not support SD protocol. The D0 line stucks at 0 V. The sd card comes fat32 formatted. 


I'm new to this protocol and did not find any good documentation / application notes / getting started sheets. So, something like that would be very helpful too.


Thanks in advance!





function [1] 




function [2]




function [3]




function [4]