can't use HAL_UARTEx_ReceiveToIdle_DMA() with IDLE event

[simon_12542]

Hello,
I am trying to use the HAL_UARTEx_ReceiveToIdle_DMA function() but the IDLE function don't work.

I call the function here :

 

 

/* Extern variables */
extern UART_HandleTypeDef huart4;
extern osEventFlagsId_t comEventHandle;
extern osMessageQueueId_t sensorQueueHandle;
extern osEventFlagsId_t regEventHandle;
extern DMA_HandleTypeDef hdma_uart4_rx;

static void modbus_receive_DMA(void) {
 buf_rec = 0; // reset the counter of received bytes in the buffer

 /* Reset pin for receiving data */
 HAL_GPIO_WritePin(RS485_SIEMENS_RE_GPIO_Port, RS485_SIEMENS_RE_Pin, GPIO_PIN_RESET);

 if (HAL_UARTEx_ReceiveToIdle_DMA(&huart4, nmbs.msg.buf, sizeof(nmbs.msg.buf)) != HAL_OK) {
 log_debug("HAL_UARTEx_ReceiveToIdle_DMA error");
 }

}

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart) {
 if (huart == &huart4) {
 modbus_receive_DMA();
 }
}

void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size) {
 if (huart == &huart4) {
 switch (HAL_UARTEx_GetRxEventType(huart)) {
 case HAL_UART_RXEVENT_IDLE: // when Idle event occurred prior reception has
 // been completed (nb of received data is lower
 // than expected one).
 packet_sended = 0; // clear flag of transmit
 buf_rec = Size; // set size of received data

 nmbs_error res_poll = nmbs_server_poll(&nmbs);
 if (NMBS_ERROR_NONE != res_poll) {
 // This will probably never happen, since we don't return < 0 in our
 // platform funcs
 }

 // If there was no packet transmission, then we immediately switch to
 // receive mode. Otherwise, this function will trigger an interrupt at the
 // end of DMA packet transmission
 if (!packet_sended)
 modbus_receive_DMA();

 break;
 }
 }
}

 

 

I have tryed to replace sizeof(nmbs.msg.buf) by 1 or 2 or 3 and it works but not in IDLE mode. So the function HAL_UARTEx_RxEventCallback works but not in the right way. I have seen on the forum lot of topics with the same problem but I am not able to fix it with my micro..

Do you have any idea ?

[TDK]

Probably you are not handling the half-complete interrupt.

What is sizeof(nmbs.msg.buf)?

How many bytes are you expecting at the IDLE event?

How many bytes does it say are received?

/**
 * @brief Provide Rx Event type that has lead to RxEvent callback execution.
 * @note When HAL_UARTEx_ReceiveToIdle_IT() or HAL_UARTEx_ReceiveToIdle_DMA() API are called, progress
 * of reception process is provided to application through calls of Rx Event callback (either default one
 * HAL_UARTEx_RxEventCallback() or user registered one). As several types of events could occur (IDLE event,
 * Half Transfer, or Transfer Complete), this function allows to retrieve the Rx Event type that has lead
 * to Rx Event callback execution.
 * @note This function is expected to be called within the user implementation of Rx Event Callback,
 * in order to provide the accurate value :
 * In Interrupt Mode :
 * - HAL_UART_RXEVENT_TC : when Reception has been completed (expected nb of data has been received)
 * - HAL_UART_RXEVENT_IDLE : when Idle event occurred prior reception has been completed (nb of
 * received data is lower than expected one)
 * In DMA Mode :
 * - HAL_UART_RXEVENT_TC : when Reception has been completed (expected nb of data has been received)
 * - HAL_UART_RXEVENT_HT : when half of expected nb of data has been received
 * - HAL_UART_RXEVENT_IDLE : when Idle event occurred prior reception has been completed (nb of
 * received data is lower than expected one).
 * In DMA mode, RxEvent callback could be called several times;
 * When DMA is configured in Normal Mode, HT event does not stop Reception process;
 * When DMA is configured in Circular Mode, HT, TC or IDLE events don't stop Reception process;
 * @PAram huart UART handle.
 * @retval Rx Event Type (return vale will be a value of @ref UART_RxEvent_Type_Values)
 */
HAL_UART_RxEventTypeTypeDef HAL_UARTEx_GetRxEventType(const UART_HandleTypeDef *huart)

[simon_12542]

Hello TDK,

I have tried to disabled the IT at the half-complete :

 

 if (HAL_UARTEx_ReceiveToIdle_DMA(&huart4, nmbs.msg.buf, sizeof(nmbs.msg.buf)) != HAL_OK) {
 log_debug("HAL_UARTEx_ReceiveToIdle_DMA error");
 }
__HAL_DMA_DISABLE_IT(&hdma_uart4_rx, DMA_IT_HT);

 

  but nothing changed
the size of sizeof(nmbs.msg.buf) is 260. I just tested it now with a lenght of 20. Nothing changed.. :

 

typedef struct nmbs_t {
 struct {
 uint8_t buf[260];
 uint16_t buf_idx;

 uint8_t unit_id;
 uint8_t fc;
 uint16_t transaction_id;
 bool broadcast;
 bool ignored;
 } msg;

 nmbs_callbacks callbacks;

 int32_t byte_timeout_ms;
 int32_t read_timeout_ms;

 nmbs_platform_conf platform;

 uint8_t address_rtu;
 uint8_t dest_address_rtu;
 uint16_t current_tid;
} nmbs_t;

 

I am expecting (for my current test) 8bytes.

How many bytes does it say are received? I don't know how to check that.

 

[Karl Yamashita]

Size is not technically the amount of bytes received, but actually a pointer to where the DMA saved the last byte in the buffer. Size is not zero based, so it starts at 1 and goes up to <size of your buffer>

 

See this project. This uses a pointer to keep track of the DMA data that is being received.

https://github.com/karlyamashita/Nucleo-G071RB_UART_DMA_Idle_Circular/wiki

 

[simon_12542]

Thanks @Karl Yamashita ,

I have tried with 1, and I could go to the function but not in idle mode.
I have tried with 8, same.. But with 16, it is not working.

In the example you gave me, I don't see my mistake..

I don't know if it is important but the interrupt of the function UART4_IRQHandler(void) works only ones. After one interrupt, I don't have any other interrupt.

[TDK]

Does HAL_UARTEx_RxEventCallback get called ever? If so, what is the value of Size when it is called?

If not, what flags are causing UART4_IRQHandler to be called? The UART4->SR register should show these immediately after the interrupt is called.

[Karl Yamashita]

---

I have tryed to replace sizeof(nmbs.msg.buf) by 1 or 2 or 3 and it works but not in IDLE mode.

---

It may have something to do with the amount of bytes you are trying to receive versus the actual amount being received.

Take a look at this project as it might help you set the amount of bytes you want the DMA ro receive in idle mode. https://github.com/karlyamashita/Nucleo-G431RB_Three_UART/wiki

 

[simon_12542]

Thank you Karl,
The DMA doesn't work since the new STM32G473. I have tried with your example but it is not working with the G473 and the NULL byte. I have gave up, and change to normal UART IT. Thank you for your help.