In the Cube IDE library there is this function
/**
* @brief Transmit and Receive an amount of data in blocking mode.
* @param hspi pointer to a SPI_HandleTypeDef structure that contains
* the configuration information for SPI module.
* @param pTxData pointer to transmission data buffer
* @param pRxData pointer to reception data buffer
* @param Size amount of data to be sent and received
* @param Timeout Timeout duration
* @retval HAL status
*/
HAL_StatusTypeDef HAL_SPI_TransmitReceive(SPI_HandleTypeDef *hspi, uint8_t *pTxData, uint8_t *pRxData, uint16_t Size,
uint32_t Timeout)
{
uint16_t initial_TxXferCount;
uint32_t tmp_mode;
HAL_SPI_StateTypeDef tmp_state;
uint32_t tickstart;
/* Variable used to alternate Rx and Tx during transfer */
uint32_t txallowed = 1U;
HAL_StatusTypeDef errorcode = HAL_OK;
/* Check Direction parameter */
assert_param(IS_SPI_DIRECTION_2LINES(hspi->Init.Direction));
/* Process Locked */
__HAL_LOCK(hspi);
/* Init tickstart for timeout management*/
tickstart = HAL_GetTick();
/* Init temporary variables */
tmp_state = hspi->State;
tmp_mode = hspi->Init.Mode;
initial_TxXferCount = Size;
if (!((tmp_state == HAL_SPI_STATE_READY) || \
((tmp_mode == SPI_MODE_MASTER) && (hspi->Init.Direction == SPI_DIRECTION_2LINES) && (tmp_state == HAL_SPI_STATE_BUSY_RX))))
{
errorcode = HAL_BUSY;
goto error;
}
if ((pTxData == NULL) || (pRxData == NULL) || (Size == 0U))
{
errorcode = HAL_ERROR;
goto error;
}
/* Don't overwrite in case of HAL_SPI_STATE_BUSY_RX */
if (hspi->State != HAL_SPI_STATE_BUSY_RX)
{
hspi->State = HAL_SPI_STATE_BUSY_TX_RX;
}
/* Set the transaction information */
hspi->ErrorCode = HAL_SPI_ERROR_NONE;
hspi->pRxBuffPtr = (uint8_t *)pRxData;
hspi->RxXferCount = Size;
hspi->RxXferSize = Size;
hspi->pTxBuffPtr = (uint8_t *)pTxData;
hspi->TxXferCount = Size;
hspi->TxXferSize = Size;
/*Init field not used in handle to zero */
hspi->RxISR = NULL;
hspi->TxISR = NULL;
#if (USE_SPI_CRC != 0U)
/* Reset CRC Calculation */
if (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE)
{
SPI_RESET_CRC(hspi);
}
#endif /* USE_SPI_CRC */
/* Check if the SPI is already enabled */
if ((hspi->Instance->CR1 & SPI_CR1_SPE) != SPI_CR1_SPE)
{
/* Enable SPI peripheral */
__HAL_SPI_ENABLE(hspi);
}
/* Transmit and Receive data in 16 Bit mode */
if (hspi->Init.DataSize == SPI_DATASIZE_16BIT)
{
if ((hspi->Init.Mode == SPI_MODE_SLAVE) || (initial_TxXferCount == 0x01U))
{
hspi->Instance->DR = *((uint16_t *)hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint16_t);
hspi->TxXferCount--;
}
while ((hspi->TxXferCount > 0U) || (hspi->RxXferCount > 0U))
{
/* Check TXE flag */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE)) && (hspi->TxXferCount > 0U) && (txallowed == 1U))
{
hspi->Instance->DR = *((uint16_t *)hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint16_t);
hspi->TxXferCount--;
/* Next Data is a reception (Rx). Tx not allowed */
txallowed = 0U;
#if (USE_SPI_CRC != 0U)
/* Enable CRC Transmission */
if ((hspi->TxXferCount == 0U) && (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE))
{
SET_BIT(hspi->Instance->CR1, SPI_CR1_CRCNEXT);
}
#endif /* USE_SPI_CRC */
}
/* Check RXNE flag */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_RXNE)) && (hspi->RxXferCount > 0U))
{
*((uint16_t *)hspi->pRxBuffPtr) = (uint16_t)hspi->Instance->DR;
hspi->pRxBuffPtr += sizeof(uint16_t);
hspi->RxXferCount--;
/* Next Data is a Transmission (Tx). Tx is allowed */
txallowed = 1U;
}
if (((HAL_GetTick() - tickstart) >= Timeout) && (Timeout != HAL_MAX_DELAY))
{
errorcode = HAL_TIMEOUT;
goto error;
}
}
}
/* Transmit and Receive data in 8 Bit mode */
else
{
if ((hspi->Init.Mode == SPI_MODE_SLAVE) || (initial_TxXferCount == 0x01U))
{
*((__IO uint8_t *)&hspi->Instance->DR) = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint8_t);
hspi->TxXferCount--;
}
while ((hspi->TxXferCount > 0U) || (hspi->RxXferCount > 0U))
{
/* Check TXE flag */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE)) && (hspi->TxXferCount > 0U) && (txallowed == 1U))
{
*(__IO uint8_t *)&hspi->Instance->DR = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr++;
hspi->TxXferCount--;
/* Next Data is a reception (Rx). Tx not allowed */
txallowed = 0U;
#if (USE_SPI_CRC != 0U)
/* Enable CRC Transmission */
if ((hspi->TxXferCount == 0U) && (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE))
{
SET_BIT(hspi->Instance->CR1, SPI_CR1_CRCNEXT);
}
#endif /* USE_SPI_CRC */
}
/* Wait until RXNE flag is reset */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_RXNE)) && (hspi->RxXferCount > 0U))
{
(*(uint8_t *)hspi->pRxBuffPtr) = hspi->Instance->DR;
hspi->pRxBuffPtr++;
hspi->RxXferCount--;
/* Next Data is a Transmission (Tx). Tx is allowed */
txallowed = 1U;
}
if ((((HAL_GetTick() - tickstart) >= Timeout) && ((Timeout != HAL_MAX_DELAY))) || (Timeout == 0U))
{
errorcode = HAL_TIMEOUT;
goto error;
}
}
}
#if (USE_SPI_CRC != 0U)
/* Read CRC from DR to close CRC calculation process */
if (hspi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLE)
{
/* Wait until TXE flag */
if (SPI_WaitFlagStateUntilTimeout(hspi, SPI_FLAG_RXNE, SET, Timeout, tickstart) != HAL_OK)
{
/* Error on the CRC reception */
SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_CRC);
errorcode = HAL_TIMEOUT;
goto error;
}
/* Read CRC */
READ_REG(hspi->Instance->DR);
}
/* Check if CRC error occurred */
if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_CRCERR))
{
SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_CRC);
/* Clear CRC Flag */
__HAL_SPI_CLEAR_CRCERRFLAG(hspi);
errorcode = HAL_ERROR;
}
#endif /* USE_SPI_CRC */
/* Check the end of the transaction */
if (SPI_EndRxTxTransaction(hspi, Timeout, tickstart) != HAL_OK)
{
errorcode = HAL_ERROR;
hspi->ErrorCode = HAL_SPI_ERROR_FLAG;
goto error;
}
/* Clear overrun flag in 2 Lines communication mode because received is not read */
if (hspi->Init.Direction == SPI_DIRECTION_2LINES)
{
__HAL_SPI_CLEAR_OVRFLAG(hspi);
}
error :
hspi->State = HAL_SPI_STATE_READY;
__HAL_UNLOCK(hspi);
return errorcode;
}
It makes a provision for every possible operating mode, which I don't need, but more to the point it seems to have a timeout on things which cannot possibly fail unless a) the SPI is not configured or b) the silicon is defective.
It also needs a timer tick i.e. interrupts running.
I am doing a boot loader which doesn't have interrupts and just needs a simple byte mode, so I cut it down as follows:
HAL_StatusTypeDef B_HAL_SPI_TransmitReceive(SPI_HandleTypeDef *hspi, uint8_t *pTxData, uint8_t *pRxData, uint16_t Size,
uint32_t Timeout)
{
uint16_t initial_TxXferCount;
uint32_t tmp_mode;
HAL_SPI_StateTypeDef tmp_state;
// uint32_t tickstart;
/* Variable used to alternate Rx and Tx during transfer */
uint32_t txallowed = 1U;
HAL_StatusTypeDef errorcode = HAL_OK;
/* Init temporary variables */
tmp_state = hspi->State;
tmp_mode = hspi->Init.Mode;
initial_TxXferCount = Size;
if (!((tmp_state == HAL_SPI_STATE_READY) || \
((tmp_mode == SPI_MODE_MASTER) && (hspi->Init.Direction == SPI_DIRECTION_2LINES) && (tmp_state == HAL_SPI_STATE_BUSY_RX))))
{
errorcode = HAL_BUSY;
goto error;
}
if ((pTxData == NULL) || (pRxData == NULL) || (Size == 0U))
{
errorcode = HAL_ERROR;
goto error;
}
/* Don't overwrite in case of HAL_SPI_STATE_BUSY_RX */
if (hspi->State != HAL_SPI_STATE_BUSY_RX)
{
hspi->State = HAL_SPI_STATE_BUSY_TX_RX;
}
/* Set the transaction information */
hspi->ErrorCode = HAL_SPI_ERROR_NONE;
hspi->pRxBuffPtr = (uint8_t *)pRxData;
hspi->RxXferCount = Size;
hspi->RxXferSize = Size;
hspi->pTxBuffPtr = (uint8_t *)pTxData;
hspi->TxXferCount = Size;
hspi->TxXferSize = Size;
/*Init field not used in handle to zero */
hspi->RxISR = NULL;
hspi->TxISR = NULL;
/* Check if the SPI is already enabled */
if ((hspi->Instance->CR1 & SPI_CR1_SPE) != SPI_CR1_SPE)
{
/* Enable SPI peripheral */
__HAL_SPI_ENABLE(hspi);
}
/* Transmit and Receive data in 8 Bit mode */
if ((hspi->Init.Mode == SPI_MODE_SLAVE) || (initial_TxXferCount == 0x01U))
{
*((__IO uint8_t *)&hspi->Instance->DR) = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint8_t);
hspi->TxXferCount--;
}
while ((hspi->TxXferCount > 0U) || (hspi->RxXferCount > 0U))
{
/* Check TXE flag */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE)) && (hspi->TxXferCount > 0U) && (txallowed == 1U))
{
*(__IO uint8_t *)&hspi->Instance->DR = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr++;
hspi->TxXferCount--;
/* Next Data is a reception (Rx). Tx not allowed */
txallowed = 0U;
}
/* Wait until RXNE flag is reset */
if ((__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_RXNE)) && (hspi->RxXferCount > 0U))
{
(*(uint8_t *)hspi->pRxBuffPtr) = hspi->Instance->DR;
hspi->pRxBuffPtr++;
hspi->RxXferCount--;
/* Next Data is a Transmission (Tx). Tx is allowed */
txallowed = 1U;
}
}
/* Clear overrun flag in 2 Lines communication mode because received is not read */
if (hspi->Init.Direction == SPI_DIRECTION_2LINES)
{
__HAL_SPI_CLEAR_OVRFLAG(hspi);
}
error :
hspi->State = HAL_SPI_STATE_READY;
return errorcode;
}
Is this correct? It does work!
There is no need for a timeout because there is nothing useful to do if this function hangs. I wonder if some other error conditions are similarly superfluous. In fact I am pretty confused about a lot of the ST code... SPI is supposed to be quite simple - like a UART. TX empty = put a byte in. RX not empty = take a byte out. One difference is that SPI always transmits and receives concurrently, using the common clock.
The function needs to be blocking, in my code, because while I could usefully do something else, it gets too complicated. AFAICT these functions wait for the operation to finish.
Many thanks for looking at this bloated code!
Similarly I "simplified" these two functions:
(timeout is no longer used)
HAL_StatusTypeDef HAL_SPI_Transmit(SPI_HandleTypeDef *hspi, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
// uint32_t tickstart;
HAL_StatusTypeDef errorcode = HAL_OK;
uint16_t initial_TxXferCount;
initial_TxXferCount = Size;
if (hspi->State != HAL_SPI_STATE_READY)
{
errorcode = HAL_BUSY;
goto error;
}
if ((pData == NULL) || (Size == 0U))
{
errorcode = HAL_ERROR;
goto error;
}
/* Set the transaction information */
hspi->State = HAL_SPI_STATE_BUSY_TX;
hspi->ErrorCode = HAL_SPI_ERROR_NONE;
hspi->pTxBuffPtr = (uint8_t *)pData;
hspi->TxXferSize = Size;
hspi->TxXferCount = Size;
/*Init field not used in handle to zero */
hspi->pRxBuffPtr = (uint8_t *)NULL;
hspi->RxXferSize = 0U;
hspi->RxXferCount = 0U;
hspi->TxISR = NULL;
hspi->RxISR = NULL;
/* Configure communication direction : 1Line */
if (hspi->Init.Direction == SPI_DIRECTION_1LINE)
{
SPI_1LINE_TX(hspi);
}
/* Check if the SPI is already enabled */
if ((hspi->Instance->CR1 & SPI_CR1_SPE) != SPI_CR1_SPE)
{
/* Enable SPI peripheral */
__HAL_SPI_ENABLE(hspi);
}
/* Transmit data in 8 Bit mode */
if ((hspi->Init.Mode == SPI_MODE_SLAVE) || (initial_TxXferCount == 0x01U))
{
*((__IO uint8_t *)&hspi->Instance->DR) = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint8_t);
hspi->TxXferCount--;
}
while (hspi->TxXferCount > 0U)
{
/* Wait until TXE flag is set to send data */
if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE))
{
*((__IO uint8_t *)&hspi->Instance->DR) = (*hspi->pTxBuffPtr);
hspi->pTxBuffPtr += sizeof(uint8_t);
hspi->TxXferCount--;
}
}
/* Clear overrun flag in 2 Lines communication mode because received is not read */
if (hspi->Init.Direction == SPI_DIRECTION_2LINES)
{
__HAL_SPI_CLEAR_OVRFLAG(hspi);
}
if (hspi->ErrorCode != HAL_SPI_ERROR_NONE)
{
errorcode = HAL_ERROR;
}
error:
hspi->State = HAL_SPI_STATE_READY;
return errorcode;
}
HAL_StatusTypeDef HAL_SPI_Receive(SPI_HandleTypeDef *hspi, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
// uint32_t tickstart;
HAL_StatusTypeDef errorcode = HAL_OK;
if ((hspi->Init.Mode == SPI_MODE_MASTER) && (hspi->Init.Direction == SPI_DIRECTION_2LINES))
{
hspi->State = HAL_SPI_STATE_BUSY_RX;
/* Call transmit-receive function to send Dummy data on Tx line and generate clock on CLK line */
return B_HAL_SPI_TransmitReceive(hspi, pData, pData, Size, Timeout);
}
if (hspi->State != HAL_SPI_STATE_READY)
{
errorcode = HAL_BUSY;
goto error;
}
if ((pData == NULL) || (Size == 0U))
{
errorcode = HAL_ERROR;
goto error;
}
/* Set the transaction information */
hspi->State = HAL_SPI_STATE_BUSY_RX;
hspi->ErrorCode = HAL_SPI_ERROR_NONE;
hspi->pRxBuffPtr = (uint8_t *)pData;
hspi->RxXferSize = Size;
hspi->RxXferCount = Size;
/*Init field not used in handle to zero */
hspi->pTxBuffPtr = (uint8_t *)NULL;
hspi->TxXferSize = 0U;
hspi->TxXferCount = 0U;
hspi->RxISR = NULL;
hspi->TxISR = NULL;
/* Configure communication direction: 1Line */
if (hspi->Init.Direction == SPI_DIRECTION_1LINE)
{
SPI_1LINE_RX(hspi);
}
/* Check if the SPI is already enabled */
if ((hspi->Instance->CR1 & SPI_CR1_SPE) != SPI_CR1_SPE)
{
/* Enable SPI peripheral */
__HAL_SPI_ENABLE(hspi);
}
/* Receive data in 8 Bit mode */
/* Transfer loop */
while (hspi->RxXferCount > 0U)
{
/* Check the RXNE flag */
if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_RXNE))
{
/* read the received data */
(* (uint8_t *)hspi->pRxBuffPtr) = *(__IO uint8_t *)&hspi->Instance->DR;
hspi->pRxBuffPtr += sizeof(uint8_t);
hspi->RxXferCount--;
}
}
if (hspi->ErrorCode != HAL_SPI_ERROR_NONE)
{
errorcode = HAL_ERROR;
}
error :
hspi->State = HAL_SPI_STATE_READY;
return errorcode;
}