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Fix #79 IMU interrupt not trigerring on STM32 #81

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Merged
merged 3 commits into from
Sep 23, 2025
Merged

Fix #79 IMU interrupt not trigerring on STM32 #81

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ba09f88
Fix #79 imu interrupt not firing on STM32
EnzoPB Sep 19, 2025
72cad84
Merge branch 'qqqlab:main' into fix-stm-interrupt
EnzoPB Sep 23, 2025
d2dce95
set imu interrupt to the highest priority
EnzoPB Sep 23, 2025
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24 changes: 24 additions & 0 deletions src/hal/STM32/hal_STM32_cpp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -200,6 +200,30 @@ void hal_print_pin_name(int pinnum) {
}
}

IRQn_Type hal_get_irqn_from_pin(int pin) {
// converts an arduino pin number to a STM32 HAL interrupt id
// taken from https://github.com/stm32duino/Arduino_Core_STM32/blob/main/libraries/SrcWrapper/src/stm32/interrupt.cpp#L158
PinName pinName = digitalPinToPinName(pin);
uint16_t gpioPin = STM_GPIO_PIN(pinName);
uint8_t id = 0;

while (gpioPin != 0x0001) {
gpioPin = gpioPin >> 1;
id++;
}

switch (id) {
case 0: return EXTI0_IRQn;
case 1: return EXTI1_IRQn;
case 2: return EXTI2_IRQn;
case 3: return EXTI3_IRQn;
case 4: return EXTI4_IRQn;
case 5: case 6: case 7: case 8: case 9:
return EXTI9_5_IRQn;
default:
return EXTI15_10_IRQn;
}
}

MF_Serial* hal_get_ser_bus(int bus_id, int baud, MF_SerialMode mode, bool invert) {
if(bus_id < 0 || bus_id >= HAL_SER_NUM) return nullptr;
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5 changes: 5 additions & 0 deletions src/imu/imu_cpp.h
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Expand Up @@ -389,6 +389,11 @@ void _imu_ll_interrupt_handler();
void _imu_ll_interrupt_setup(int interrupt_pin) {
Serial.println(MF_MOD ": IMU_EXEC_IRQ");
attachInterrupt(digitalPinToInterrupt(interrupt_pin), _imu_ll_interrupt_handler, RISING);
#ifdef ARDUINO_ARCH_STM32
// (#79) on stm32, increase the interrupt priority, otherwise it does not get called
// configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY is the maximum priority allowed for interrupts that needs to call FreeRTOS api
HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), 0, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY);
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I know this works, but does not make sense to me. See

https://stackoverflow.com/questions/50243996/what-are-valid-values-of-hal-nvic-setpriority-when-using-stm32-and-freertos

as far as I understand it configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY is a interrupt priority, but in the HAL_NVIC_SetPriority call it is used as a subpriority.

Why not use HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), 0, 0); i.e. use the highest priority?

Or use HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY, 0);, but I'm not sure if this will fix the issue.

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You're right, I mixed up preempt priority & subpriority. It worked because the preempt priority was 0 (the highest).

HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY, 0); doesn't work, which seems logical since configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY's value is already the default preempt priority.

Why not use HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), 0, 0); i.e. use the highest priority?

Because using a priority higher than configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY will not allow the ISR to call FreeRTOS functions (FreeRTOSConfig_Default.h).
It looks like no FreeRTOS calls are made in the imu ISR, so it's ok to use a priority > configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY, but that is something to remember for future development.

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Currently on STM32 the whole imu interrupt (including imu_loop() ) runs in interrupt context. So probably will have issues as soon as SDCARD (uses separate task) is implemented for STM32.

On ESP32/RP2 the imu stuff runs as high priority task, which is notified by the imu interrupt. I could not get this to work on STM32, but I did not make a big effort on this...

Anyway - to move ahead and get at least the interrupt working again:

Let's go with HAL_NVIC_SetPriority(hal_get_irqn_from_pin(interrupt_pin), 0, 0), as this will trigger the imu interrupt for sure.

Maybe enclose everything (including IRQn_Type hal_get_irqn_from_pin(int pin)) with #ifdef MF_STM32_INTERRUPT_HACK instead of #ifdef ARDUINO_ARCH_STM32 and set #define MF_STM32_INTERRUPT_HACK 1 at the beginning of in hal_stm32_cpp.h with some comments. Makes it easier to find this hack back later.

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Maybe enclose everything (including IRQn_Type hal_get_irqn_from_pin(int pin)) with #ifdef MF_STM32_INTERRUPT_HACK instead of #ifdef ARDUINO_ARCH_STM32 and set #define MF_STM32_INTERRUPT_HACK 1 at the beginning of in hal_stm32_cpp.h with some comments. Makes it easier to find this hack back later.

This won't worlk - leave as is...

#endif
}

inline void _imu_ll_interrupt_handler2() {
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