SPI Interrupt Driven Slave Receive Error
I am using STM32H7B3I-DK running a touchgfx application and acting as SPI Master, and Nucleo-H743ZI as SPI Slave. Both are configured in interrupt mode not using HWNSS.
The Master is sending 1,2,3,4,5,6,7,8 but the slave is receiving random numbers
I am sending one byte at a time and receiving one byte then adding it to a buffer. I want to avoid HAL overhead as much as possible as the data needs to be close to real time.
The Master seems to send quickly enough using HAL_SPI_Transmit; however, the slave would only receive every other byte, hence the avoidance of HAL on the Slave side.
The master is properly sending data, as checked by oscilloscope. I have double checked the compatible settings for Master-Slave communication in the .ioc files such as Data Size, First Bit, etc...
Here is my following relevant code for the master:
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_256;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 0x0;
hspi2.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
hspi2.Init.NSSPolarity = SPI_NSS_POLARITY_LOW;
hspi2.Init.FifoThreshold = SPI_FIFO_THRESHOLD_01DATA;
hspi2.Init.TxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi2.Init.RxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi2.Init.MasterSSIdleness = SPI_MASTER_SS_IDLENESS_00CYCLE;
hspi2.Init.MasterInterDataIdleness = SPI_MASTER_INTERDATA_IDLENESS_00CYCLE;
hspi2.Init.MasterReceiverAutoSusp = SPI_MASTER_RX_AUTOSUSP_DISABLE;
hspi2.Init.MasterKeepIOState = SPI_MASTER_KEEP_IO_STATE_ENABLE;
hspi2.Init.IOSwap = SPI_IO_SWAP_DISABLE;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
[...]
for(;;)
{
HAL_GPIO_WritePin(GPIOI, GPIO_PIN_0, GPIO_PIN_RESET); // Pull CS low
HAL_Delay(5);
for (int i = 0; i < 8; i++) {
data[i] = i+1;
HAL_SPI_Transmit(&hspi2, &data[i], 1, HAL_MAX_DELAY); // Transmit one byte
}
HAL_GPIO_WritePin(GPIOI, GPIO_PIN_0, GPIO_PIN_SET); // Pull CS high
HAL_Delay(100);
}
Here is the relevant Slave code:
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_SLAVE;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_2EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 0x0;
hspi1.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
hspi1.Init.NSSPolarity = SPI_NSS_POLARITY_LOW;
hspi1.Init.FifoThreshold = SPI_FIFO_THRESHOLD_01DATA;
hspi1.Init.TxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi1.Init.RxCRCInitializationPattern = SPI_CRC_INITIALIZATION_ALL_ZERO_PATTERN;
hspi1.Init.MasterSSIdleness = SPI_MASTER_SS_IDLENESS_00CYCLE;
hspi1.Init.MasterInterDataIdleness = SPI_MASTER_INTERDATA_IDLENESS_00CYCLE;
hspi1.Init.MasterReceiverAutoSusp = SPI_MASTER_RX_AUTOSUSP_DISABLE;
hspi1.Init.MasterKeepIOState = SPI_MASTER_KEEP_IO_STATE_DISABLE;
hspi1.Init.IOSwap = SPI_IO_SWAP_DISABLE;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
Error_Handler();
}
[...]
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
if (GPIO_Pin == GPIO_PIN_14) {
if (HAL_GPIO_ReadPin(GPIOD, GPIO_PIN_14) == GPIO_PIN_RESET) {
__HAL_SPI_ENABLE(&hspi1);
__HAL_SPI_DISABLE_IT(&hspi1, (SPI_IT_TXP | SPI_IT_DXP | SPI_IT_EOT | SPI_IT_TXTF | SPI_IT_UDR | SPI_IT_OVR | SPI_IT_CRCERR | SPI_IT_FRE | SPI_IT_MODF | SPI_IT_TSERF | SPI_IT_ERR));
__HAL_SPI_ENABLE_IT(&hspi1, SPI_IT_RXP);
}
}
}
void spiISR(SPI_HandleTypeDef *hspi){
if (hspi1.Instance->SR & SPI_FLAG_RXP) {
rxBuffer[rxIndex] = SPI1->RXDR;
// Increment index and wrap around if necessary
rxIndex = (rxIndex + 1) % RX_BUFFER_SIZE;
__HAL_SPI_CLEAR_EOTFLAG(hspi);
__HAL_SPI_CLEAR_OVRFLAG(hspi);
__HAL_SPI_CLEAR_FREFLAG(hspi);
}
}
In stm32h7xx_it.c I do the following in the SPI_IRQHandler to avoid calling the large HAL_SPI_IRQHandler :
void SPI1_IRQHandler(void)
{
/* USER CODE BEGIN SPI1_IRQn 0 */
spiISR(&hspi1);
return;
/* USER CODE END SPI1_IRQn 0 */
HAL_SPI_IRQHandler(&hspi1);
/* USER CODE BEGIN SPI1_IRQn 1 */
/* USER CODE END SPI1_IRQn 1 */
}