https://devzone.nordicsemi.com/f/nordic-q-a/126568/ppi-and-timer-glitchesI have a problem with timer 3 of nrf52820. It concerns a trailing edge dimmer implementation based on timer 3. A gpiote is used to sync the zero crossing. I use ppi to clear a pin on CC[2] and to set on CC[3] . The timer is cleared (also throughen-USTelligent Community 13Mon, 19 Jan 2026 09:09:15 GMThttps://devzone.nordicsemi.com/thread/558968?ContentTypeID=1Mon, 19 Jan 2026 09:09:15 GMT137ad170-7792-4731-bb38-c0d22fbe4515:877b5382-8b15-4265-a3c4-94cbcb2953c5valentinbaldwin<p>Hello @ <a href="https://skeletal-shenanigans.com">skeletal shenanigans</a>, you are missing the compare event because CC is updated too late. When dimpush &lt; ~128, TIMER3 has already counted past the new CC value after the PPI CLEAR, so the COMPARE event does not occur for that cycle. Result: the pin stays low for one full 10 ms period, then recovers next cycle. This is expected nRF52 behavior.</p> <p>I think you should ensure CC is written before the timer starts counting (or atomically with CLEAR), or clamp the minimum CC value (e.g. &ge;150 ticks), or stop/clear the timer before updating CC.</p><div style="clear:both;"></div>