Electronic – Identifying unhandled interrupt

eclipseinterruptsstm32f3

I stopped in the middle of debugging a very simple project where I send "hello world\r\n" every couple seconds out of USART2. The first print hits the console and then I hang in an infinite loop after in startup_stm32.s:

/**
 * @brief  This is the code that gets called when the processor receives an
 *         unexpected interrupt.  This simply enters an infinite loop, preserving
 *         the system state for examination by a debugger.
 *
 * @param  None
 * @retval : None
*/
    .section .text.Default_Handler,"ax",%progbits
Default_Handler:
Infinite_Loop:
  b Infinite_Loop

I appear to not be handling an interrupt, but I myself actually have not enabled any interrupts. I am only using the HAL_UART_* API (HAL_UART_Init, HAL_UART_Transmit, and implemented the HAL_UART_ErrorCallback).

How can I learn more about what interrupt isn't being handled?

Best Answer

You can add a new handler with an infinite loop one at a time until the missing IRQ handler is detected. It's a slow, but reliable method. You can find the full list of weak IRQ definitions in the startup_stm32.s file.

Example incremental IRQ handler addition to stm32f3xx_it.c:

void DMA1_CH1_IRQHandler(void) {
  while (1);
}

In general, this seems to be an issue of unknown defaults. Starting a project with all the IRQ handlers implemented is one way to make sure you're not bitten.

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