diff --git a/firmware/common/clkin.c b/firmware/common/clkin.c
index bef8b8a9..080d02d0 100644
--- a/firmware/common/clkin.c
+++ b/firmware/common/clkin.c
@@ -52,8 +52,7 @@ void clkin_detect_init(void)
 	timer_set_prescaler(TIMER3, 0);
 	timer_set_mode(TIMER3, TIMER_CTCR_MODE_TIMER);
 	TIMER3_MCR = TIMER_MCR_MR0R;
-	TIMER3_EMR = TIMER_EMR_EM0 | TIMER_EMR_EM3 |
-		(TIMER_EMR_EMC_SET << TIMER_EMR_EMC0_SHIFT) |
+	TIMER3_EMR = (TIMER_EMR_EMC_SET << TIMER_EMR_EMC0_SHIFT) |
 		(TIMER_EMR_EMC_TOGGLE << TIMER_EMR_EMC3_SHIFT);
 	TIMER3_MR3 = MEASUREMENT_CYCLES;
 	TIMER3_MR0 = MEASUREMENT_CYCLES;