H7A3 SDMMC 2 not working, system stall at MX_SDMMC2_SD_Init().

[AScha.3]

Hello, when testing the SDcard on SDIO 1-bit interface , we see a big problem here:

when card in slot, cpu stall in MX_SDMMC2_SD_Init() , on debug can see: card info sector count, block size etc. read seem ok, but then waiting for response -- forever. (timeout -1)

SDclk set to 200/(4*2) MHz, 1-bit mode; tried different things: cache on/off, clk faster/slow, extra cap close to card holder, different cards, core volt.scale 0/1; now i am out of ideas, why it is not working. looked also H7A3 errata, but there i see no problem with SD .

Stall/wait is here, in init :

 while (!__HAL_SD_GET_FLAG(hsd, SDMMC_FLAG_RXOVERR | SDMMC_FLAG_DCRCFAIL | SDMMC_FLAG_DTIMEOUT | SDMMC_FLAG_DATAEND))

so: what is wrong? do i something wrong? or is something missing?

[Imen.D]

Hello @AScha.3​ and welcome to the STM32 Community,

I added the adequate topics to your question in order to increase its chance to be reviewed by our experts.

Which CubeMX and CubeH7 package version are you using ?

If possible to share your ioc file or the source code to check more this behavior.

Have a look at this AN5200 "Getting started with STM32H7 Series SDMMC host controller", which contains typical examples and it may help you on the SDMMC configuration.

Imen

[AScha.3 · Accepted solution]

Thx for your response.

AN5200 was on my list...and i use STM32CubeIDE, Version: 1.6.1, cube  6.2.1-RC2 ;

with update to actual version and after "right" setting of pins got it working now.

Read-speed about 3,4 MB/s , 1bit mode;

setting: 200Mhz clk, div 2 (gives clk/4 -> 50MHz SDHC standard; pins CMD+D0 : pullup, speed medium ("FAST" on H7A3 ).

With same setting also running on STM32H753 now.

and on my small STM32F411 board, 100MHz clk, div 0 (!) , 4 bit mode, all pins: pullup and high speed, get about 8MB/s read from microSD. =)

(speed is effective speed, including f_read() and without DMA , tested with 10KB block reading)

just what STM could do better: when using cube -> in RCC LSE clock initial setting : LSE drive -> high drive cap. This would save a lot of people wondering, why cpu not always start or stall .

and here, for SDMMC , setting for pins : pullups and medium/fast speed setting.

regards

Alfred

[Imen.D]

Hi @AScha.3​ ,

Really glad to know you overcame this problem :)

Thank you for all the details you provided. I will let our teams know about your suggestion.

Thank you once more for your contribution.

Imen