diff --git a/Makefile b/Makefile
index dc5608a..8c163f1 100644
--- a/Makefile
+++ b/Makefile
@@ -12,12 +12,11 @@ LDFLAGS += -mmcu=$(MCU)
 AVDFLAGS += -p $(MCU)
 AVDFLAGS += -c usbtiny
 
-CLOCK_HZ = 1600000
+CLOCK_HZ = 16000000
 FUSES += -U lfuse:w:0x7f:m
 FUSES += -U hfuse:w:0xdd:m
 FUSES += -U efuse:w:0xff:m
 
-
 upload: .upload
 
 .upload: $(PROG).hex
@@ -28,9 +27,10 @@ fuses:
 	avrdude $(AVDFLAGS) $(FUSES)
 	
 main: main.o avr.o
+blink: blink.o avr.o
 avr.o: CFLAGS += -DCLOCK_HZ=$(CLOCK_HZ)
 
-$(PROG).hex: $(PROG)
+%.hex: %
 	avr-objcopy -O ihex -R .eeprom -R .fuse -R .lock -R .signature $< $@
 
 clean:
diff --git a/avr.c b/avr.c
index 14b1d2c..f85a573 100644
--- a/avr.c
+++ b/avr.c
@@ -5,8 +5,8 @@
 #include "avr.h"
 
 /* Clock must be a multiple of 2MHz or there will be clock drift */
-#define TICKS_PER_SECOND (CLOCK_HZ / 64)
-#define TICKS_PER_JIFFY (TICKS_PER_SECOND / 10)
+#define TICK_HZ (CLOCK_HZ / 8 / 64)
+#define TICKS_PER_JIFFY (TICK_HZ / 10)
 
 #define cbi(byt, bit)   (byt &= ~_BV(bit))
 #define sbi(byt, bit)   (byt |= _BV(bit))
@@ -31,10 +31,11 @@ init(void)
 
 	TCCR1A = 0;
 	TCCR1B = 0;
-	TCNT1 = 0;
+	TCNT1 = 0; // reset counter
+
 	OCR1A = TICKS_PER_JIFFY - 1;
 	TCCR1B |= _BV(WGM12);
-	TCCR1B |= _BV(CS11) | _BV(CS10);
+	TCCR1B |= _BV(CS11) | _BV(CS10); // prescale: clk_io / 64
 	TIMSK1 |= _BV(OCIE1A);
 	
 	bit(PORTA, _BV(7), true);
diff --git a/blink.c b/blink.c
index 745985b..11952a9 100644
--- a/blink.c
+++ b/blink.c
@@ -1,41 +1,31 @@
+#include <stdbool.h>
 #include <avr/io.h>
 #include <avr/interrupt.h>
 
-/* This only works out for a 16MHz or 8MHz clock */
-#define CLOCK_HZ 16000000
-#define TICKS_PER_SECOND (CLOCK_HZ / 256)
-#define TICKS_PER_JIFFY (TICKS_PER_SECOND / 10)
+#include "avr.h"
 
 volatile uint32_t jiffies = 0;
+volatile bool tick = false;
 
-ISR(TIM1_COMPA_vect)
+void
+loop(void)
 {
-	jiffies += 1;
+	if (tick) {
+		tick = false;
+
+		if (jiffies % 10 == 0) {
+			PORTB ^= 0xff;
+		}
+	}
 }
 
 int
 main(void)
 {
-	unsigned char counter;
+	init();
 
-	/*
-	 * set PORTB for output
-	 */
-	DDRB = 0xFF;
-	PORTB = 0x00;
-
-	TCCR1A = 0;
-	TCCR1B = 0;
-	TCNT1 = 0;
-	OCR1A = TICKS_PER_JIFFY - 1;
-	TCCR1B |= (1 << WGM12);
-	TCCR1B |= (1 << CS12);
-	TIMSK1 |= (1 << OCIE1A);
-
-	sei();
-
-	while (1) {
-		PORTB = 0xFF * ((jiffies/ 10) % 2);
+	for (;;) {
+		loop();
 	}
 
 	return 0;
diff --git a/brain.fzz b/brain.fzz
index 9f92ee1..071aebf 100644
Binary files a/brain.fzz and b/brain.fzz differ
diff --git a/main.c b/main.c
index 26bd0e8..35384fc 100644
--- a/main.c
+++ b/main.c
@@ -145,8 +145,8 @@ draw()
 		return;
 	}
 
-	jclk = (abs(jam_clock / 600) % 10) * 1000;
-	jclk += abs(jam_clock) % 600;
+	jclk = (abs(jam_clock / 10) / 60) * 100;
+	jclk += abs(jam_clock / 10) % 60;
 
 	pclk = (abs(period_clock / 10) / 60) * 100;
 	pclk += abs(period_clock / 10) % 60;
@@ -170,10 +170,7 @@ draw()
 #endif
 
 	// Score A
-	write_num(score_b, 2);
-
-	// Jam clock, least significant half
-	write_num(jclk % 100, 2);
+	write_num(score_b, 3);
 
 	// Period clock
 	if (blank) {
@@ -190,11 +187,11 @@ draw()
 		write_num(pclk, 4);
 	}
 
-	// Jam clock, most significant half
-	write_num(jclk / 100, 2);
+	// Jam clock
+	write_num(jclk, 3);
 
 	// Score A
-	write_num(score_a, 2);
+	write_num(score_a, 3);
 
 	if (false) {
 		int i;