STM32 U5A9 SPI DMAPause and DMAResume are empty

[G_Anastasopoulos]

Dear All,

I am working on the STM32U5A9 platform. I am migrating to this MCU a project that was developed on the STM32F7, that was using the HAL_SPI_DMAPause and HAL_SPI_DMAResume functions.

Looking into the HAL of the U5 I see this:

Why are these functions deprecated? What would be the best course of action in order to achieve the same functionality as before on the U5?

Thank you in advance.

[Imen.D]

Hello @G_Anastasopoulos ,

HAL_SPI_DMAPause() and HAL_SPI_DMAResume() are not supported here as mentioned that are maintained for backward compatibility reasons.

In this SPI version -for example- we can abort the transfert if we are using the DMA, this is because the RXDMAEN & TXDMAEN are write protected when SPI is enabled, which means once the SPI instance is enabled the state of those two bits cannot be modified.

[G_Anastasopoulos]

Dear @Imen.D 

In order to get my code working I saw what these functions looked like in the F7 HAL and I took them and adjusted them to look like this:

static HAL_StatusTypeDef SPI_DMA_Pause(SPI_HandleTypeDef* hspi) {
	if (hspi->Instance == SPI1){
    __HAL_LOCK(hspi);

    /* Disable the SPI DMA Tx & Rx requests */
    CLEAR_BIT(hspi->Instance->CFG1, SPI_CFG1_TXDMAEN);

    /* Unlock the process */
    __HAL_UNLOCK(hspi);
	}
    return HAL_OK;
}

static HAL_StatusTypeDef SPI_DMA_Resume(SPI_HandleTypeDef* hspi) {
	if (hspi->Instance == SPI1){
    /* Process Locked */
    __HAL_LOCK(hspi);

    /* Enable the SPI DMA Tx & Rx requests */
    SET_BIT(hspi->Instance->CFG1, SPI_CFG1_TXDMAEN);

    /* Process Unlocked */
    __HAL_UNLOCK(hspi);
	}
    return HAL_OK;
}

With debugging I can see that the value of the CFG1 register changes when I either clear or set the bit.

How is this possible?

[G_Anastasopoulos]

Dear@Imen.D 

I have found in the documentation of the STM32U5 the following passage:

From this I am deducting that what you have mentioned earlier is incorrect.

My implementation for the stop, pause and resume functionality is the following and perhaps you should implement it in the next version of the libraries for this MCU:

static HAL_StatusTypeDef SPI_DMA_Pause(SPI_HandleTypeDef* hspi) {
    __HAL_LOCK(hspi);

    /* Disable the SPI DMA Tx & Rx requests */
    CLEAR_BIT(hspi->Instance->CFG1, SPI_CFG1_TXDMAEN | SPI_CFG1_RXDMAEN);

    /* Unlock the process */
    __HAL_UNLOCK(hspi);
    return HAL_OK;
}

static HAL_StatusTypeDef SPI_DMA_Resume(SPI_HandleTypeDef* hspi) {

    /* Process Locked */
    __HAL_LOCK(hspi);

    /* Enable the SPI DMA Tx & Rx requests */
    SET_BIT(hspi->Instance->CFG1, SPI_CFG1_TXDMAEN | SPI_CFG1_RXDMAEN);

    /* Process Unlocked */
    __HAL_UNLOCK(hspi);
    return HAL_OK;
}

HAL_StatusTypeDef SPI_DMA_Stop(SPI_HandleTypeDef* hspi) {
    HAL_StatusTypeDef errorcode = HAL_OK;
    //? The Lock is not implemented on this API to allow the user application
    //? to call the HAL SPI API under callbacks HAL_SPI_TxCpltCallback() or HAL_SPI_RxCpltCallback() or HAL_SPI_TxRxCpltCallback():
    //? when calling HAL_DMA_Abort() API the DMA TX/RX Transfer complete interrupt is generated
    //? and the correspond call back is executed HAL_SPI_TxCpltCallback() or HAL_SPI_RxCpltCallback() or HAL_SPI_TxRxCpltCallback()

    //- Abort the SPI DMA tx Stream/Channel
    if (hspi->hdmatx != NULL) {
        if (HAL_OK != HAL_DMA_Abort(hspi->hdmatx)) {
            SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_DMA);
            errorcode = HAL_ERROR;
        }
    }
    //- Abort the SPI DMA rx Stream/Channel
    if (hspi->hdmarx != NULL) {
        if (HAL_OK != HAL_DMA_Abort(hspi->hdmarx)) {
            SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_DMA);
            errorcode = HAL_ERROR;
        }
    }

    //- Disable the SPI DMA Tx & Rx requests
    CLEAR_BIT(hspi->Instance->CR2, SPI_CFG1_TXDMAEN | SPI_CFG1_RXDMAEN);
    hspi->State = HAL_SPI_STATE_READY;
    return errorcode;
}