usart receive

[soundarya_h_s]

USART receive is not providing the output please check and reply me asap

selected USART2 made it to asynchronous also enabled global interrupt
code lines that i have added

uint8_t txbuf[10]="hello ";

uint8_t rxbuf[10];

 

while (1)

{

/* USER CODE END WHILE */

HAL_UART_Receive(&huart2, rxbuf, sizeof(rxbuf), 100);

/* USER CODE BEGIN 3 */

}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)

{

HAL_UART_Transmit(&huart2, rxbuf, sizeof(rxbuf), 100);

}

[KDJEM.1]

Hello @soundarya_h_s ,

If you using the interrupt mode, the transmit and receive functions are HAL_UART_Transmit_IT() and HAL_UART_Receive_IT(). For that, I recommend you to take a look to this FAQ: How to use STM32 HAL UART driver API and Callbacks ?

Also, I think Getting started with UART can help you.

Thank you.

Kaouthar

[soundarya_h_s]

@KDJEM.1 i tried disabling the global interrupt but i am not getting output

 

[Karl Yamashita]

HAL_UART_RxCpltCallback only works when interrupt is enabled. HAL_UART_Receive is only polling and will not trigger an interrupt callback. If you want polling then you have to rewrite your code to transmit what you received.

[Karl Yamashita]

A better approach is to use the idle interrupt. That way you can receive any length string. You make your array size the longest string/bytes you'll expect. Then when you call HAL_UARTEx_ReceiveToIdle_IT, you pass an argument twice the size of your array. That way you'll either get an idle interrupt or if you're expecting like 5 bytes from "hello", it'll do a half callback interrupt. 

 

 

#define RX_BUFFER_SIZE 10
typedef struct
{
	int dataRdy;
	uint32_t size;
}RX_Status;
uint8_t rxbuf[RX_BUFFER_SIZE];

RX_Status rx_status = {0};


int main(void)
{
 HAL_UARTEx_ReceiveToIdle_IT(&huart2, rxbuf, RX_BUFFER_SIZE * 2);
 while (1)
 {
	 if(rx_status.dataRdy)
	 {
		 rx_status.dataRdy = 0;
		 HAL_UART_Transmit_IT(&huart2, rxbuf, rx_status.size);
	 }
 }
}

void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size)
{
	if(huart == &huart2)
	{
		rx_status.dataRdy = 1;
		rx_status.size = Size;
		HAL_UARTEx_ReceiveToIdle_IT(&huart2, rxbuf, RX_BUFFER_SIZE * 2);
	}
}

 

 

Make sure you enable UART interrupt

 

 

[Piranha]

Those zero timeouts for the HAL_UART_Transmit() calls are especially cool...

[Tesla DeLorean]

Making my head spin, things that need to be global and volatile.

Cramming data into a single byte, that might go out on an EXTI

Pulling data from an active DMA buffer.

Lot of disconnected code, ideas and concepts here.

[soundarya_h_s]

@Tesla DeLorean can you please  tell it in simple words or modify the code which you think is not correct

[Karl Yamashita]

What is connected to your UART tx pin?