force "rising" variable to be 0 or 1

diff --git a/main.c b/main.c
index 923a8ea..67661d6 100644 (file)
--- a/main.c
+++ b/main.c
@@ -177,7 +177,7 @@ static void poll_input_capture(void)
        icp = ICR1;
        sei();
 
-       rising = TCCR1B & _BV(ICES1);
+       rising = !!(TCCR1B & _BV(ICES1));
 
        /* change the edge type */
        TCCR1B ^= _BV(ICES1);