diff --git a/time.c b/time.c
index f9a4295..16c9782 100644
--- a/time.c
+++ b/time.c
@@ -4,25 +4,34 @@
 #include <avr/interrupt.h>
 #include <avr/io.h>
 
-volatile unsigned int _eigentime_ms;
+volatile struct eigentime_s _eigentime_ms;
 
 void
 time_init(void)
 {
-	_eigentime_ms = 0;
-	TCCR1B = _BV(CS10);
-	OCR1A = TIMER1_COMPA_VALUE;
-	TIMSK |= _BV(OCIE1A);
+	_eigentime_ms.low = 0;
+	_eigentime_ms.high = 0;
+	// prescaler is 64.
+	TCCR0B = _BV(CS00) | _BV(CS01);
+	TIMSK0 |= _BV(TOIE0);
+	sei();
 }
 
 
-unsigned int 
-get_eigentime(void)
+void
+get_eigentime(struct eigentime_s * time)
 {
-	return _eigentime_ms;
+	time->low = _eigentime_ms.low;
+	time->high = _eigentime_ms.high;
 }
 
-ISR(TIMER1_COMPA_vect)
+ISR(TIMER0_OVF_vect)
 {
-	_eigentime_ms++;
+	unsigned int last_eigentime_low = _eigentime_ms.low;
+	_eigentime_ms.low += TIME_MILLIS_PER_OVERFLOW;
+	// Handle the overflow.
+	if(_eigentime_ms.low < last_eigentime_low)
+	{
+		_eigentime_ms.high++;
+	}
 }
diff --git a/time.h b/time.h
index 9f465c2..ef88cb9 100644
--- a/time.h
+++ b/time.h
@@ -2,13 +2,19 @@
 #define _TIME_H_
 #include "conf.h"
 
-#define TIMER1_MAX_VALUE 0xffff
-#define TIMER1_COMPA_VALUE (TIMER1_MAX_VALUE / F_CPU)
+// This is 2.04 = 2ms
+#define TIME_MILLIS_PER_OVERFLOW (0xff * 1000UL * 64) / F_CPU
 
-extern volatile unsigned int _eigentime_ms;
+// for 32bit eigentime
+struct eigentime_s
+{
+	unsigned int low, high;
+};
 
-unsigned int 
-get_eigentime(void);
+extern volatile struct eigentime_s _eigentime_ms;
+
+void
+get_eigentime(struct eigentime_s * time);
 
 void
 time_init(void);