STM32H755 stalls when SDMMC interface is enabled

SDMMC has a number of clocking choices, watch if it reconfigures any of the other PLL's, or changes "peripheral clocks"

Thanks for your answer, however, the program already stalls before the init function of the SDMMC interface is reached. This is what baffles me. A line in the code that is never reached influences the behavior prior to this line.

Yes, thought about this, too. But when I disable the line where D-cache is enabled, it stalls a few lines later but it stalls still before the sd card enable function. I didnt have this problem on the H743...

Oh boi... after a weekend yelling at my computer I figured out what was going wrong:

First of all, the programm got stuck in the init function of the SD card. The reason why I thought it got stucked earlier was that after updating CubeIDE the debugging dind't work as it did before. I had to adjust following line for the M7 core so that I don't get a timeout:

/* USER CODE BEGIN Boot_Mode_Sequence_1 */
 /* Wait until CPU2 boots and enters in stop mode or timeout*/
 timeout = 0xFFFF;
 //while((__HAL_RCC_GET_FLAG(RCC_FLAG_D2CKRDY) != RESET) && (timeout-- > 0));
 while((__HAL_RCC_GET_FLAG(RCC_FLAG_D2CKRDY) != RESET));
 if ( timeout < 0 )
 {
 Error_Handler();
 }

The reason why the program crashed was that I did not fitted the SD card when I launched the program. Normally that would be no problem. When I compare the code to earlier versions I observe followinf difference. When using SDMMC and FATFS you will geht following code in the init function:

static void MX_SDMMC1_SD_Init(void)
{
 
 /* USER CODE BEGIN SDMMC1_Init 0 */
 
 /* USER CODE END SDMMC1_Init 0 */
 
 /* USER CODE BEGIN SDMMC1_Init 1 */
 
 /* USER CODE END SDMMC1_Init 1 */
 hsd1.Instance = SDMMC1;
 hsd1.Init.ClockEdge = SDMMC_CLOCK_EDGE_RISING;
 hsd1.Init.ClockPowerSave = SDMMC_CLOCK_POWER_SAVE_DISABLE;
 hsd1.Init.BusWide = SDMMC_BUS_WIDE_4B;
 hsd1.Init.HardwareFlowControl = SDMMC_HARDWARE_FLOW_CONTROL_DISABLE;
 hsd1.Init.ClockDiv = 2;
 hsd1.Init.TranceiverPresent = SDMMC_TRANSCEIVER_NOT_PRESENT;
 /* USER CODE BEGIN SDMMC1_Init 2 */
 
 /* USER CODE END SDMMC1_Init 2 */
 
}

For the newer firmeware version I get:

static void MX_SDMMC1_SD_Init(void)
{
 
 /* USER CODE BEGIN SDMMC1_Init 0 */
 
 /* USER CODE END SDMMC1_Init 0 */
 
 /* USER CODE BEGIN SDMMC1_Init 1 */
 
 /* USER CODE END SDMMC1_Init 1 */
 hsd1.Instance = SDMMC1;
 hsd1.Init.ClockEdge = SDMMC_CLOCK_EDGE_RISING;
 hsd1.Init.ClockPowerSave = SDMMC_CLOCK_POWER_SAVE_DISABLE;
 hsd1.Init.BusWide = SDMMC_BUS_WIDE_1B;
 hsd1.Init.HardwareFlowControl = SDMMC_HARDWARE_FLOW_CONTROL_DISABLE;
 hsd1.Init.ClockDiv = 4;
 hsd1.Init.TranceiverPresent = SDMMC_TRANSCEIVER_NOT_PRESENT;
 if (HAL_SD_Init(&hsd1) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN SDMMC1_Init 2 */
 
 /* USER CODE END SDMMC1_Init 2 */
 
}

In the former version HAL_SD_Init(&hsd1) was called during f_mount. If you do not have an SD cdard fitted f_mount would return an error. In the newer version you will get stuck in the error handler. You have to have your SD card inserted before the CPU starts. I do not know why this was changed, it does not make any sense in my opinion.

At least I have an explanation for the observed behaviour. SD card ist still not working (as expected, nothing is working out of the box without deep-diving into the code) but now I fan focus on the usual trouble with dma and so on. Can the IDMA of the SDMMC interface access RAM3 region?

Regards,

Daniel

Ok, I have it all running now. SDMMC1 cannot access RAM 3. With SDMMC2 and the appropriate MPU settings it's finally working. Was a hard fight though...

@Curtis ,

Hello, can you tell me, what was the trick to get sdmmc2 running? i have same problem on H7A3, stall when HAL_SD_Init , but info from card seems read ok, blocksize etc. is read, but then wait for SD-status --- forever . (-1) . ooohhh...

It stalls, because if the init fails the error handler is called. As I mentioned above I am very unhappy with th code generation of CubeIDE in this case.

I got it running when I changed the buffer from RAM3 to RAM2. SDMMC2 IDMA cannot access RAM3, but I don't know if this applies for the H7A3, too. However, I got it only running in 1 Bit mode. 4 Bit mode was impossible to implement. I gave it up after weeks, however 1 Bit mode is sufficient for the current application.

Regards,

Daniel

Thx for info.

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 ).

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)

regards

Alfred

You mentioned that you have ist running on the H7 in 1-Bit mode; did you try 4 bit mode for the H7, too?

not on this board, no need for more speed here, only D0 is routed. (at work)

(private) for my audio-player, tried high speed with 4 bit mode on F411 ; working same as 1 bit mode, just have about 50mm cpu--cardholder wires, all pullup on , no hardware (resistors), just 10uF cer.cap close to card. (without didnt work...), because from SDcard datasheet: card can pull up to 350mA for short times, when switching to hi speed.