Hi
I’m seeing continuous interrupts caused by the comparator output toggling when using DAC references for COMP1/COMP2 on an STM32L496. Please help.
Hardware / high-level setup
MCU: STM32L496VGT6
Comparator mode: Non-inverting (single) and window comparator (COMP1/COMP2 used as window)
Reference sources: DAC outputs used as VH and VL (DAC1/2)
Sensing node: ADC pin (voltage from pressure transmitter) → comparator non-inverting input
Purpose: comparator output drives EXTI to run motor control when pressure crosses thresholds
Expected thresholds (after divider / DAC settings)
VH = 0.55 V
VL = 0.275 V
Observed behavior:
Note: my front-end uses a 2:1 voltage divider, so the comparator input = Vin / 2 (e.g. Vin = 1.10 V → comparator sees 0.55 V; Vin = 0.55 V → comparator sees 0.275 V).
When Vin (transmitter output) is about 1.05–1.07 V, I get continuous rising-edge events (COMP output toggles repeatedly).
When Vin is about 0.51–0.54 V, I get continuous falling-edge events.
The EXTI/IRQ is fired repeatedly while Vin sits in those bands.
I tested the same functionality on the NUCLEO-L496ZG board, and it worked correctly. However, I am observing this issue on the custom PCB. Please review the attached schematic photos and kindly help me resolve this problem.
