Delayed ISR on Button Press for Nucleo STM32WB55

[Shreyas_Corvid]

Hello,

I am using the Nucleo STM32WB55 board and noticed that when I press the user button, the interrupt service routine (ISR) is triggered only after about 3.5–4 seconds. This delay occurs even before reaching the callback function — the ISR itself is reached late.

I have not initialized or configured any BLE stack functionality; this is just a basic GPIO interrupt setup. I have also used other Nucleo boards and never experienced this kind of delay.

Has anyone else encountered this issue or found a solution?

Thanks,
Shreyas

[gbm · Accepted solution]

Check if the pull-up resistor is enabled on button input port line.

[Shreyas_Corvid]

Enabling the pull-up on the button input fixed the issue. The interrupt now fires immediately.

Thanks
Shreyas