use pullup for input to avoid noise

diff --git a/main.c b/main.c
index 5849b8b..3509874 100644 (file)
--- a/main.c
+++ b/main.c
@@ -160,6 +160,9 @@ int main(void)
        uint8_t t, diff;
        uint8_t tmp;
 
+       /* use pull-up for inputs */
+       PORTC |= 0x3f;
+
        /* LED */
        DDRB = 0x02;