STM32F103RE combined UART receive via interrupt

[AAnju.1]

Hi,I'am using STM32F103RE. i have enable 3 usart for GSM modem(USART1), Debug(UART4) and GPS(UART2). now i need to collect data under interrupt routing. it should be something like this, this is for ATMEL:D

ISR(USART0_TX_vect)
{
 byte myChar= UDR0 ;
}

i need to handle interrupt individually. i used this

HAL_UART_Receive_IT(&huart1,(uint8_t *)buff,10); 

but i have to call this everytime when i need read the receiver pin

i'am using STMcubeMX and KeiluVision

Thank in advance

[KnarfB]

If you generate the code using STM32CubeMX, check the USARTx global interrupt in the NVIC settings tab of all three UARTs. Then, the re-generated code has three interrupt handlers in stm32f1xx_it.c. They look like

void USART1_IRQHandler(void)
{
 /* USER CODE BEGIN USART1_IRQn 0 */
 
 /* USER CODE END USART1_IRQn 0 */
 HAL_UART_IRQHandler(&huart1);
 /* USER CODE BEGIN USART1_IRQn 1 */
 
 /* USER CODE END USART1_IRQn 1 */
}

etc.. You can see that the HAL handles the interrupt. HAL_UART_IRQHandler analyses the various interrupt sources and finally calls so-called callback functions. You define the callback functions you need e.g. in main.c like ordinary functions:

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{ 
 if(huart->Instance==USART1) {
 ... // read out buff
 }
 ...
}

The callback naming must exactly match. See the comments and source code in stm32f1xx_hal_uart.c.

The pure HAL mechanism has some overhead and does not fit advanced use cases. But it should work okay for 3 UARTs.

Note that NMEA telegram parsing has been discussed here quite often. Using a char by char rx interrupt seems adequate. For more advanced UART handling see https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx

[TDK]

If you want to handle individual bytes, you will need to call HAL_UART_Receive_IT with a buffer of length 1. HAL isn't set up to handle receiving individual bytes.

You could also roll your own solution checking for the RXNE bit in the ISR.