[GitHub] [mynewt-core] andrzej-kaczmarek commented on a change in pull request #2126: hw/mcu/nordic: Fix hal_timer firing too early

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andrzej-kaczmarek commented on a change in pull request #2126: hw/mcu/nordic: Fix hal_timer firing too early
URL: https://github.com/apache/mynewt-core/pull/2126#discussion_r356202330
 
 

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 File path: hw/mcu/nordic/nrf52xxx/src/hal_timer.c
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 @@ -168,11 +168,15 @@ nrf_timer_set_ocmp(struct nrf52_hal_timer *bsptimer, uint32_t expiry)
          * The nrf documentation states that you must set the output
          * compare to 2 greater than the counter to guarantee an interrupt.
          * Since the counter can tick once while we check, we make sure
-         * it is greater than 2.
+         * it is greater than 2. Otherwise enable TICK event so we can get an
+         * interrupt at proper tick (also we may get an extra interrupt, but
+         * we will just not handle any timer there).
          */
         if (delta_t < 3) {
 
 Review comment:
   you're right. and now actually I think we should also set pending interrupt when delta==1 because the timer can tick once so TICK interrupt will happen on next tick which is also one tick too late. so something like this should work I think:
   delta==2 enable tick and wait for proper tick (we may have 1 or 2 additional "empty" interrupts)
   delta==1 enable tick and set irq pending (we may have 0 or 1 "empty" interrupt)
   delta==0 set irq pending
   
   does this make sense?

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