cpu/stm32/periph_timer: fix spurious IRQs

maribu · maribu · commit 6673c3aca94f · 2022-11-25T08:25:52.000+01:00
(cherry picked from commit 20fc71d)
diff --git a/cpu/stm32/periph/timer.c b/cpu/stm32/periph/timer.c
@@ -136,6 +136,10 @@ int timer_set_absolute(tim_t tim, int channel, unsigned int value)
     }
 #endif
 
+    /* clear spurious IRQs */
+    dev(tim)->SR &= ~(TIM_SR_CC1IF << channel);
+
+    /* enable IRQ */
     dev(tim)->DIER |= (TIM_DIER_CC1IE << channel);
     irq_restore(irqstate);
 
@@ -166,6 +170,11 @@ int timer_set_periodic(tim_t tim, int channel, unsigned int value, uint8_t flags
     }
 
     TIM_CHAN(tim, channel) = value;
+
+    /* clear spurious IRQs */
+    dev(tim)->SR &= ~(TIM_SR_CC1IF << channel);
+
+    /* enable IRQ */
     dev(tim)->DIER |= (TIM_DIER_CC1IE << channel);
 
     if (flags & TIM_FLAG_RESET_ON_MATCH) {
