diff --git a/dda_queue.c b/dda_queue.c
index 3ef2665..87effa7 100644
--- a/dda_queue.c
+++ b/dda_queue.c
@@ -84,7 +84,7 @@ void enqueue(TARGET *t) {
 	#endif
 
 	// fire up in case we're not running yet
-	if (TIMSK1 == 0)
+	if (timerInterruptIsEnabled() == 0)
 		next_move();
 }
 
diff --git a/timer.h b/timer.h
index 67773a8..810273d 100644
--- a/timer.h
+++ b/timer.h
@@ -30,5 +30,6 @@ void delayMicrosecondsInterruptible(unsigned int us);
 
 #define enableTimerInterrupt()	do { TIMSK1 |= (1<<OCIE1A); } while (0)
 #define disableTimerInterrupt() do { TIMSK1 &= ~(1<<OCIE1A); } while (0)
+#define timerInterruptIsEnabled() (TIMSK1 & (1 << OCIE1A))
 
 #endif	/* _TIMER_H */