ST67W61 - failing to receive correct boot sequence

[Southbranch]

Hi!

I am trying a very simple test to receive the correct boot-up sequence which should be 0x55 0xAA and I am using this code:

void ST67W_test(void)
{
  printf("\r\n*** Bare-metal ST67W SPI Test ***\r\n");

  // 1. Turn module ON
  HAL_GPIO_WritePin(CHIP_EN_GPIO_Port, CHIP_EN_Pin, GPIO_PIN_SET);

  // 2. Wait for RDY = HIGH (boot event present)
  while (HAL_GPIO_ReadPin(SPI_RDY_GPIO_Port, SPI_RDY_Pin) == GPIO_PIN_RESET) {;}

  // 3. Assert CS = HIGH (begin frame)
  HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_SET);

  // 4. Perform SPI transfer
  uint8_t tx[8] = {0};
  uint8_t rx[8] = {0};
  if (HAL_SPI_TransmitReceive(&NCP_SPI_HANDLE, tx, rx, 8, 100) != HAL_OK)
  {
    printf("\r\nSPI transfer failed!\r\n");
    HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_RESET);
    return;
  }

  printf("\r\nRX: %02X %02X %02X %02X %02X %02X %02X %02X\r\n", 
                  rx[0], rx[1], rx[2], rx[3], rx[4], rx[5], rx[6], rx[7]);

  // 5. CS = LOW -> end of frame
  HAL_GPIO_WritePin(SPI_CS_GPIO_Port, SPI_CS_Pin, GPIO_PIN_RESET);
 
  // 6. Done, turn off module
  HAL_GPIO_WritePin(CHIP_EN_GPIO_Port, CHIP_EN_Pin, GPIO_PIN_RESET);
}

I have tried three different boards with the NUCLEO-67W61M1 but with the same faulty result:

*** Bare-metal ST67W SPI Test ***
Waiting for SPI_RDY...
RDY boot detected.
RX: 01 55 00 00 00 00 01 00

Feels like some timing issue, but I am using the same SPI settings as in CubeMX examples:

Many thanks in advance for any hints