The SPIM3 module of the nrf52840 causes the app_timer to fail to trigger after communication, and this issue only affects timers that are triggered once. Timers that are triggered repeatedly are not affected；https://devzone.nordicsemi.com/f/nordic-q-a/127452/the-spim3-module-of-the-nrf52840-causes-the-app_timer-to-fail-to-trigger-after-communication-and-this-issue-only-affects-timers-that-are-triggered-once-timers-that-are-triggered-repeatedly-are-not-affectedIf I call app_timer_stop(ble_recv_timeout_id) before starting the timer, the system will crash after running at most 7 times: this is my timer code:en-USTelligent Community 13Tue, 17 Mar 2026 16:31:44 GMTRE: The SPIM3 module of the nrf52840 causes the app_timer to fail to trigger after communication, and this issue only affects timers that are triggered once. Timers that are triggered repeatedly are not affected；https://devzone.nordicsemi.com/thread/563490?ContentTypeID=1Tue, 17 Mar 2026 16:31:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b973e9e8-a488-4f2f-b328-518ea1d1ecbaKenneth<p>Hello,</p> <p>It&#39;s been a long time since nRF5 SDK , so it might be that you trigger an unknown issue here, if you start and stop timers very quickly, so you may need to try to avoid that. That said, you can try to set&nbsp;MAX_RTC_TASKS_DELAY 100 (instead of 47) in \components\libraries\timer\app_timer.c. I do remember that the default value was a bit too optimistic.</p> <p>I am not sure if you are using the&nbsp;APP_TIMER_CONFIG_USE_SCHEDULER, you can see if that helps.</p> <p>Also try to increase&nbsp;APP_TIMER_CONFIG_OP_QUEUE_SIZE in case that has an impact and enable&nbsp;APP_TIMER_KEEPS_RTC_ACTIVE.</p> <p>Kenneth</p> <p></p><div style="clear:both;"></div>