--- a/blackbox/lowlevel.c	Sat Dec 10 10:51:24 2011 +0100
+++ b/blackbox/lowlevel.c	Sat Dec 10 14:12:09 2011 +0100
@@ -111,7 +111,7 @@
     // setup data bit + carid timer
     TCCR2 = (1<<CS21) | (1<<WGM21); //divide by 8, set compare match
     OCR2 = TIMER2_50US;
-    TIMSK |= 1<<OCIE2; //enable timer2 interrupt
+    TIMSK |= _BV(OCIE2); //enable timer2 interrupt
 
     // enable carid interrupts
     MCUCR = _BV(ISC00) | _BV(ISC01) | _BV(ISC10) | _BV(ISC11); // INT0/1 rising edge
@@ -123,7 +123,7 @@
     TCCR1B = (1<<CS11) | (1<<WGM12); //divide by 8, set compare match (1mhz clock)
     OCR1A = TIMER1_500NS;
     //OCR1A = TIMER1_7500NS;
-    TIMSK |= 1<<OCIE1A; //enable timer1 interrupt
+    TIMSK |= _BV(OCIE1A); //enable timer1 interrupt
 
     RS232_puts_p(PSTR("FreeSlot Blackbox v"));
     RS232_puts(VERSION);
@@ -133,7 +133,7 @@
 
 
 
-void check_rails_shortcut(void) {
+uint8_t check_rails_shortcut(void) {
     // check for short circuit on the rails
     uint8_t i = 100;
     if ((PIN(RAIL_DETECT_PORT) & _BV(RAIL_DETECT)) == 0) {
@@ -167,4 +167,5 @@
             }
         }
     }
+    return 0;
 }
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