Check the Peripheral Initialization
- Ensure that the peripheral generating the interrupt is properly initialized. For an STM32, this includes:
- Enabling the clock for the peripheral in the RCC (Reset and Clock Control) before service routine setup.
- Configuring the peripheral's registers to enable the desired interrupt events and settings (e.g., setting the NVIC for priority if needed).
Example:
// Enable clock for GPIO
__HAL_RCC_GPIOA_CLK_ENABLE();
// Configure the GPIO pin as interrupt
GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Pin = GPIO_PIN_0;
GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
Verify the NVIC Configuration
- Check if the NVIC (Nested Vectored Interrupt Controller) has enabled the interrupt. Ensure priority is set appropriately.
- Make sure the correct vector table is used (check if the
SCB->VTOR register points to the correct memory location).
Example:
// Enable IRQ and set priority
HAL_NVIC_SetPriority(EXTI0_IRQn, 2, 0);
HAL_NVIC_EnableIRQ(EXTI0_IRQn);
Ensure Proper ISR Declaration
- Check that the ISR function is correctly defined and matches the interrupt vector name expected in the vector table.
- Verify it’s not optimized out or has improper naming due to typos.
Example:
void EXTI0_IRQHandler(void) {
// Check and clear the interrupt flag
if (__HAL_GPIO_EXTI_GET_IT(GPIO_PIN_0) != RESET) {
__HAL_GPIO_EXTI_CLEAR_IT(GPIO_PIN_0);
// Handle the interrupt
}
}
Analyze Possible Conflict with Other Peripherals
- Other peripherals or conflicting interrupt priorities might prevent the ISR from triggering.
- Recheck priority levels if system interrupts seem busy or overriding each other.
Inspect Clock Source Configuration
- Ensure appropriate clock source settings. Incorrect clock source or configuration could affect peripheral operation, hence not generating interrupts.
- Verify that drive strength and frequency conditions meet peripheral and interrupt logic requirements.
Review Hardware Connection
- Confirm the external conditions required for triggering points (e.g., button presses, correct signals) are actually making the interrupt happen.
- Use oscilloscopes or logic analyzers to visualize actual triggered hardware states.
Debugging and Testing
- Utilize in-circuit debuggers to step through execution and verify your device hitting interrupt service breakpoints.
- Consider using semihosting or toggling GPIO as diagnostic indicators for ISR entry.
By ensuring all these areas are thoroughly reviewed and understood, you should be able to determine why the ISR for your STM32 is not being triggered and can take corrective action.
