STM32 and SPI Communication Issue

[uranyumx]

Hello,

I want to read data from a custom designed ADC chip through SPI interface. I guess there is an issue about my SPI codes, do you have any feedback on it?

SPI Baudrate: 10 Mbits/s, and the maximum SCLK frequency is 24 MHz

Codes in while loop:

uint16_t ReadADCAmplifier(uint8_t regAddress) {
  uint8_t txBuffer[2];
  uint8_t rxBuffer[2];
  txBuffer[0] = regAddress;
  txBuffer[1] = 0x00;
  HAL_GPIO_WritePin(ADCAmp_SPI2_CS_GPIO_Port, ADCAmp_SPI2_CS_Pin, GPIO_PIN_RESET);
  HAL_SPI_TransmitReceive(&hspi2, txBuffer, rxBuffer, 2, 1000);
  HAL_GPIO_WritePin(ADCAmp_SPI2_CS_GPIO_Port, ADCAmp_SPI2_CS_Pin, GPIO_PIN_SET);
  uint16_t value = ((rxBuffer[0] << 8) | rxBuffer[1]);
  return value;

SPI Settings:

static void MX_SPI2_Init(void)
{

  /* USER CODE BEGIN SPI2_Init 0 */

  /* USER CODE END SPI2_Init 0 */

  /* USER CODE BEGIN SPI2_Init 1 */

  /* USER CODE END SPI2_Init 1 */
  /* SPI2 parameter configuration*/
  hspi2.Instance = SPI2;
  hspi2.Init.Mode = SPI_MODE_MASTER;
  hspi2.Init.Direction = SPI_DIRECTION_2LINES;
  hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi2.Init.CLKPhase = SPI_PHASE_2EDGE;
  hspi2.Init.NSS = SPI_NSS_SOFT;
  hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
  hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi2.Init.CRCPolynomial = 10;
  if (HAL_SPI_Init(&hspi2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI2_Init 2 */

  /* USER CODE END SPI2_Init 2 */

}

 

[KlausST]

Hi,

Error description is missing. Thus I didn't go deep into code.

One possible issue:

(rxBuffer[0] << 8)

Rxbuffer is 8 bits wide, thus if you shift it 8 bits left it might result in zero.
Better typecast it as 16bit value.

Klaus

 

[uranyumx]

Thank you for comments @KlausST !

I modified my codes like that,

uint8_t I_Read8(uint8_t I_address, uint8_t *I_data){

    uint8_t txIBuffer[2] = {(I_address | 0x80), 0x00};
    uint8_t rxIBuffer[2];

    HAL_GPIO_WritePin(I_SPI2_CS_GPIO_Port, I_SPI2_CS_Pin, GPIO_PIN_RESET);
    uint8_t status_I = (HAL_SPI_TransmitReceive(&hspi2, txIBuffer, rxIBuffer, 2, HAL_MAX_DELAY) == HAL_OK);
    HAL_GPIO_WritePin(I_SPI2_CS_GPIO_Port, I_SPI2_CS_Pin, GPIO_PIN_SET);

    *I_data = rxIBuffer[1];

    return status_I;

}

uint8_t I_Write8(uint8_t I_address, uint8_t I_data){

    uint8_t txIBuffer[2] = {I_address, I_data};

    HAL_GPIO_WritePin(I_SPI2_CS_GPIO_Port, I_SPI2_CS_Pin, GPIO_PIN_RESET);
    uint8_t status_I = (HAL_SPI_Transmit(&hspi2, txIBuffer, 2, HAL_MAX_DELAY) == HAL_OK);
    HAL_GPIO_WritePin(I_SPI2_CS_GPIO_Port, I_SPI2_CS_Pin, GPIO_PIN_SET);

    return status_I;

}

Then to make sure that it works, I call the chip ID which was in register 63

uint8_t I_data ;
I_Read8(63, &I_data);

      HAL_Delay(100);

Then, during the debug session, in the watch window, I got 'error, target not available' message.

--- Updated Mar 13, 2023 ---

Update: I got a result which is the attached figure but it should be '2' in decimal based on the datasheet.