4 files changed, 17 insertions, 18 deletions
diff --git a/src/display.cc b/src/display.cc
index e06f271..b1b0af5 100644
--- a/src/display.cc
+++ b/src/display.cc
@@ -10,16 +10,23 @@ Display display;
 
 extern volatile uint8_t disp[8];
 
-void Display::turn_off()
+void Display::disable()
 {
 	TIMSK0 &= ~_BV(TOIE0);
 	PORTB = 0;
 	PORTD = 0;
 }
 
-void Display::turn_on()
+void Display::enable()
 {
-	TIMSK0 |= _BV(TOIE0);
+	// Ports B and D drive the dot matrix display -> set all as output
+	DDRB = 0xff;
+	DDRD = 0xff;
+
+	// Enable 8bit counter with prescaler=8 (-> timer frequency = 1MHz)
+	TCCR0A = _BV(CS01);
+	// raise timer interrupt on counter overflow (-> interrupt frequency = ~4kHz)
+	TIMSK0 = _BV(TOIE0);
 }
 
 /*
diff --git a/src/display.h b/src/display.h
index 647e474..cb263d0 100644
--- a/src/display.h
+++ b/src/display.h
@@ -7,8 +7,8 @@
 class Display {
 	public:
 		Display() {};
-		void turn_on(void);
-		void turn_off(void);
+		void enable(void);
+		void disable(void);
 };
 
 extern Display display;
diff --git a/src/main.cc b/src/main.cc
index ac8b68a..fbb40c9 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -19,20 +19,9 @@ int main (void)
 	// dito
 	wdt_disable();
 
-	// Ports B and D drive the dot matrix display -> set all as output
-	DDRB = 0xff;
-	DDRD = 0xff;
-	PORTB = 0;
-	PORTD = 0;
-
 	// Enable pull-ups on PC3 and PC7 (button pins)
 	PORTC |= _BV(PC3) | _BV(PC7);
 
-	// Enable 8bit counter with prescaler=8 (-> timer frequency = 1MHz)
-	TCCR0A = _BV(CS01);
-	// raise timer interrupt on counter overflow (-> interrupt frequency = ~4kHz)
-	TIMSK0 = _BV(TOIE0);
-
 	disp[0] = 0x01;
 	disp[1] = 0x02;
 	disp[2] = 0x04;
@@ -78,6 +67,7 @@ int main (void)
 	disp[31] = 0x00;
 #endif
 
+	display.enable();
 	modem.enable();
 
 	sei();
@@ -86,6 +76,8 @@ int main (void)
 		// nothing to do here, go to idle to save power
 		SMCR = _BV(SE);
 		asm("sleep");
+		// The display timer causes a wakeup after 256µs. Run the system
+		// loop after the timer's ISR is done.
 		rocket.loop();
 	}
 
diff --git a/src/system.cc b/src/system.cc
index b98e687..09c0f53 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -32,7 +32,7 @@ void System::loop()
 		else {
 
 			// turn off display to indicate we're about to shut down
-			display.turn_off();
+			display.disable();
 
 			modem.disable();
 
@@ -57,7 +57,7 @@ void System::loop()
 			PCMSK1 &= ~(_BV(PCINT15) | _BV(PCINT11));
 
 			// turn on display
-			display.turn_on();
+			display.enable();
 
 			// ... and modem
 			modem.enable();