How to handle Variable length receive data via UART?

[TMuka.1]

uint8_t rx_buffer[32], rx_flag, rx_index, rx_data, RxData[32];
 
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	if (huart->Instance==USART1)
	{
		//if the data is not being received, clear the buffer
		if(rx_index ==0)
		{
			for (int i=0; i<20; i++)
			{
				rx_buffer[i]=0;
			}
		}
		//if the character received is other than 'enter' ASCII13, save the data in buffer
		if(rx_data!=13)
		{
			rx_buffer[rx_index++]=rx_data;
		}
		else
		{
			rx_index=0;
			rx_flag=1;  // turn the rx_flag 'ON'
			HAL_UART_Transmit(&huart1, rx_buffer, sizeof(rx_buffer), 100); // transmit the data via UART
		}
		HAL_UART_Receive_IT(&huart1, &rx_data, 1);  // restart the interrupt reception mode & receive only 1 char at a time!
 
	}
 
}

I declared a 32byte rx_buffer[], when I send more than 32 Bytes, the board couldn't receive any more serial data through interrupts! Attached my sample callback function and code inside that portion!

Regards,

Thangz

[Guenael Cadier]

stm32l1xx_hal_msp_template.c file is not expected to be compiled. Maybe you added it the the list of objects in your projects ?

However, if you are using CubeMx, the generated stm32l1xx_hal_msp.c file should contain a valid HAL_MspInit() body (for example all peripheral clocks are to be enabled here). Without this function body, it can't work.

Could you use the previous content of HAL_MspInit() function when you were able to receive some chars ?

[_alaBaster]

@Guenael Cadier , @TMuka.1 , @TDK 

I find the solution the Guenael Cadier suggested (UART DMA circular buffer ReceptionToIdle) exactly what I am leaning to with my application (variable length commands) and I will be moving now towards the implementation.

I cannot see in the Examples\UART\ folder the UART_ReceptionToIdle_CircularDMA example for STM32L05x (CubeIDE 1.12.1)

Actually there is no implementation of HAL_UARTEx_ReceiveToIdle_DMA for STM32L0 family in stm32l0xx_hal_uart.

Can you please indicate where I could find/download examples? Or does L0 family not support this function?

Regards

[Guenael Cadier]

Hi @_alaBaster 

I think ReceiveToIdle API should be available in latest STM32L0 HAL drivers version (please check in stm32l0xx_uart_ex.c). If not, maybe you could have a look in latest  version of STM32L0 HAL drivers available on github here .
API prototypes are present in stm32l0xx_hal_driver/Src/stm32l0xx_hal_uart_ex.c

Regards

[TDK]

There aren't any examples in the L0, but you can adapt the examples for another family.

The function definition is here:

stm32l0xx_hal_driver/Src/stm32l0xx_hal_uart_ex.c at 0eac588d92ca6ab730621131c71614ce240bab8a · STMicroelectronics/stm32l0xx_hal_driver (github.com)

[_alaBaster]

Hi @Guenael Cadier got it, thanks. I was looking only at stm32l0xx_hal_uart.c

Kind regards

[_alaBaster]

ok great, thanks. Now it is time to dive into it! 🙂