Hall Sensor Encoder Issue - Left Motor Intermittent on STM32H723

[rohitkushah]

Hi everyone,

I'm using an STM32H723 for a project with Hall sensor encoders on two BLDC motors.

**Hardware:**
- Left motor: PE7, PE8, PE9 (U,V,W)
- Right motor: PD3, PD4, PD2 (U,V,W)

**Problem:**
Right motor encoder works perfectly. Left motor has issues:
1. Tick count is much lower than right motor (82 vs 236 ticks for same movement)

**Debug Output:*ENC:0,1|DIR:STOP,CW ← Left STOP, Right moving
ENC:6,11|DIR:CW,CW ← Both OK briefly
ENC:8,21|DIR:STOP,CW ← Left STOP again
ENC:82,236|DIR:CW,CW ← Huge tick difference

**What I've Tried:**
- Added debouncing
- Removed direction reset on invalid transitions
- Verified signals on oscilloscope (clean)
- External pull-ups (4.7kΩ)

**Key Difference:**
- Right motor: Dedicated EXTI2, EXTI3, EXTI4 handlers → WORKS
- Left motor: Shared EXTI9_5_IRQHandler for all 3 pins → PROBLEMS

**Questions:**
1. Can shared EXTI9_5_IRQHandler cause missed transitions when two pins change simultaneously?
2. Should I move left motor to pins with dedicated EXTI lines (0-4)?
3. Is there any way to get individual handlers for EXTI7/8/9 on H7 series?

**Code snippet (EXTI9_5 handler):**
```c
void EXTI9_5_IRQHandler(void) {
if (__HAL_GPIO_EXTI_GET_IT(L_HALL_U_PIN) != RESET) {
Hall_ProcessLeft(Hall_ReadLeftRaw());
}
// Same for V and W pins
}
Any suggestions would be greatly appreciated!

Thanks

[GMA]

Hello @rohitkushah,

Check the NVIC priority level settings of the interrupts associated with the HALL sensor.