SPI1 not working on STM32H723VEH6

[DrewBrandt]

Hi, I'm a bit new to working with STM32s but I cannot for the life of me get SPI to work on this chip.

The issue

Here is an example sketch that doesnt work for me:

#include <Arduino.h>
#include <SPI.h>

void setup()
{
  Serial.setTx(PB6_ALT2);
  Serial.setRx(PB7_ALT1);
  Serial.begin(115200);
  SPIClass spi(PD7 /* MOSI */, PB4 /* MISO */, PB3 /* SCK */, PA15 /* CS */);
  spi.begin();
  Serial.print("test");
  digitalWrite(PA15, LOW);
  spi.transfer(0xAA);
  digitalWrite(PA15, HIGH);
  Serial.print("test");
}

void loop() {}

The program simply hangs and never prints out the second test.

Troubleshooting:

I found that it end up hanging during this function from spi_com.c:

/**
  * @brief This function is implemented by user to send/receive data over
  *         SPI interface
  * @param  obj : pointer to spi_t structure
  * @param  tx_buffer : tx data to send before reception
  * @param  rx_buffer : rx data to receive if not numm
  * @param  len : length in byte of the data to send and receive
  * @retval status of the send operation (0) in case of error
  */
spi_status_e spi_transfer(spi_t *obj, const uint8_t *tx_buffer, uint8_t *rx_buffer,
                          uint16_t len)
{
  spi_status_e ret = SPI_OK;
  uint32_t tickstart, size = len;
  SPI_TypeDef *_SPI = obj->handle.Instance;
  uint8_t *tx_buf = (uint8_t *)tx_buffer;

  if (len == 0) {
    ret = SPI_ERROR;
  } else {
    tickstart = HAL_GetTick();

#if defined(SPI_CR2_TSIZE)
    /* Start transfer */
    LL_SPI_SetTransferSize(_SPI, size);
    LL_SPI_Enable(_SPI);
    LL_SPI_StartMasterTransfer(_SPI);
#endif

    while (size--) {
#if defined(SPI_SR_TXP)
      while (!LL_SPI_IsActiveFlag_TXP(_SPI));
#else
      while (!LL_SPI_IsActiveFlag_TXE(_SPI));
#endif
      LL_SPI_TransmitData8(_SPI, tx_buf ? *tx_buf++ : 0XFF);

#if defined(SPI_SR_RXP)
      while (!LL_SPI_IsActiveFlag_RXP(_SPI));
#else
      while (!LL_SPI_IsActiveFlag_RXNE(_SPI));
#endif
      if (rx_buffer) {
        *rx_buffer++ = LL_SPI_ReceiveData8(_SPI);
      } else {
        LL_SPI_ReceiveData8(_SPI);
      }
      if ((SPI_TRANSFER_TIMEOUT != HAL_MAX_DELAY) &&
          (HAL_GetTick() - tickstart >= SPI_TRANSFER_TIMEOUT)) {
        ret = SPI_TIMEOUT;
        break;
      }
    }

#if defined(SPI_IFCR_EOTC)
    // Add a delay before disabling SPI otherwise last-bit/last-clock may be truncated
    // See https://github.com/stm32duino/Arduino_Core_STM32/issues/1294
    // Computed delay is half SPI clock
    delayMicroseconds(obj->disable_delay);

    /* Close transfer */
    /* Clear flags */
    LL_SPI_ClearFlag_EOT(_SPI);
    LL_SPI_ClearFlag_TXTF(_SPI);
    /* Disable SPI peripheral */
    LL_SPI_Disable(_SPI);
#else
    /* Wait for end of transfer */
    while (LL_SPI_IsActiveFlag_BSY(_SPI));
#endif
  }
  return ret;
}

#ifdef __cplusplus
}

At the while (!LL_SPI_IsActiveFlag_RXP(_SPI));

I am way too far out of my depth to really understand what that means, but after some more research I believe it might be related to the SCK pin I'm using (PB3) also being a jtag pin, and not being allowed to be used for SCK because JTAG takes preference. I don't use JTAG and use a 6 pin ST-Link connection to program/debug the board.

---

Can someone help me understand what the problem might be? I'm not sure if it's a HW issue or a software issue, but a lot of the 'fixes' that involved disabling jtag had no effect (or I didn't implement them properly because idk what I'm doing). I also tried pinMode(PB3, OUTPUT) in setup before calling SPI.begin() but everything still hangs at the same point.

I should also mention I'm using Platformio

Thanks

[fpistm]

Hi @DrewBrandt
Your code is not correct as you set an Hardware CS and drive it by software.
So, try to change the spi instance:

-  SPIClass spi(PD7 /* MOSI */, PB4 /* MISO */, PB3 /* SCK */, PA15 /* CS */);
+ SPIClass spi(PD7 /* MOSI */, PB4 /* MISO */, PB3 /* SCK */);

and do not forget to init the CS pin:
pinMode(PA5, OUTPUT);

[DrewBrandt]

@fpistm
Thanks for the quick response. Here is what I just tried:

#include <Arduino.h>
#include <SPI.h>

void setup()
{
  Serial.setTx(PB6_ALT2);
  Serial.setRx(PB7_ALT1);
  Serial.begin(115200);
  pinMode(PA15, OUTPUT);
  // digitalWrite(PA15, HIGH);
  SPIClass spi(PD7 /* MOSI */, PB4 /* MISO */, PB3 /* SCK */);
  spi.begin();
  Serial.print("test");
  digitalWrite(PA15, LOW);
  spi.transfer(0xAA);
  digitalWrite(PA15, HIGH);
  Serial.print("test");
}

void loop() {}

Same result, never prints the second "test". I tried it with and without setting PA15 to high.

Unfortunately I did not include any test points on this PCB so that I could verify clock signals or anything like that, as I havent had an issue like this before. My only way to verify if a signal is being sent is to either see it working or strip off the solder mask :(

[DrewBrandt]

I figured it out! For some reason when I made this variant, I only did the linker script and didn't mess with the clock settings at all... Probably because I didn't really understand them. But after following this issue and this variant guide, it's all working :D. Idk if it was the right thing to do, but I went into MX, set all the peripherals I was using (I2C1, SPI1, USART1) and then let it auto configure the clocks.

[fpistm]

Thanks for the feedback. Thought it was a mcu already supported. That explain your issue + the wrong CS pin management.