I am trying to setup UART on an STM32L072CZTX. I am using interrupt mode and the interrupt seems to be firing due to a pause in main loop execution but nothing inside the interrupt seems to be occurring

[JGusl.1]

I am trying to setup UART on an STM32L072CZTX. In the ioc file I have setup the pins, RX is set to AF4 pullup, and TX is AF4 nopull. The interrupt is set to 0 and enabled. I have redefined the RxCpltCallback in the main and have events occur in there that work when run from main. I can see a pause in main execution (a simple blinking light) but nothing inside the interrupt seems to be happening, flags being set or a different LED blinking.

[Karl Yamashita]

You don't say what mode you're using to receive data. Are you polling, interrupt or DMA?

[JGusl.1]

"I am using interrupt mode"

[Karl Yamashita]

post your code for RxCpltCallback().

[JGusl.1]

volatile uint8_t  flag = 0;
 
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	flag = 1;
	//HAL_UART_Transmit(&huart1, UART_RX_BUFFER, sizeof(UART_RX_BUFFER), 100);
	//HAL_Delay(500);
	HAL_UART_Receive_IT(&huart1, UART_RX_BUFFER, 20); //restart the interrupt reception
}
main (void)
{
HAL_UART_Receive_IT(&huart1, UART_RX_BUFFER, 20);
       while (1)
	{
		if (flag == 1)
		{
 
			HAL_GPIO_WritePin(GPIOB, RED_LED, GPIO_PIN_SET);
			HAL_Delay(250);
			HAL_GPIO_WritePin(GPIOB, RED_LED, GPIO_PIN_RESET);
			HAL_Delay(250);
 
			flag = 0;
		}
		else
		{
 
			HAL_GPIO_WritePin(GPIOB, GREEN_LED, GPIO_PIN_SET);
			HAL_Delay(250);
			HAL_GPIO_WritePin(GPIOB, GREEN_LED, GPIO_PIN_RESET);
			HAL_Delay(250);
 
		}
}

[JGusl.1]

That main loop never changes to the RED_LED loop

[Karl Yamashita]

what kind of UART data are you expecting?

[JGusl.1]

Just strings. I'm trying to inject them temporarily using a serial monitor. Im sending strings longer than 20 bytes

[Karl Yamashita]

Your code looks like it should toggle the red led then back to blinking the green led. I have to drive to work now. When I get there I can try it on a dev board. What STM32 are you using and what pins are the leds on?

[JGusl.1]

STM32L072CZTX, im using PB8 and PB9, but its a custom board, not a dev board