We are in the process of porting from nRF SDK v15.3.0 to v17.1.0.
After updating, we’ve noticed that the device sometimes gets stuck. Investigation shows this is related to GPIO interrupt handling.
The nRF52840 supports two wakeup detect modes: Default detect (non-latch) and Latch detect (LDETECT). In our use case the interrupt source is not an edge but a signal that can stay active (high or low).
SDK v17 introduces new latch handling in the GPIO library. For nRF52840, this is always enabled through NRF_GPIO_LATCH_PRESENT macro.
We never explicitly enable latch mode (via NRF_GPIO->DETECTMODE = GPIO_DETECTMODE_DETECTMODE_LDETECT << GPIO_DETECTMODE_DETECTMODE_Pos;), however the ISR still uses latch detect clearing mechanisms even when this is not enabled.
Because our interrupt signals can stay active, the latch never resets → the MCU ends up stuck in the loop inside port_event_handle(uint32_t * latch) (called from interrupt context). This effectively makes every GPIO interrupt susceptible to the same issue if the input signal stays asserted.
We tested by commenting out #define NRF_GPIO_LATCH_PRESENT, and then everything works fine without latch handling — but this is not expected behaviour. We don’t want to modify the SDK just to achieve this. Is there a supported way to disable latch detect without patching the SDK?
