1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
/* timer test programm for timer2: 8bit with ctc mode */
#include <avr/interrupt.h>
volatile int timer_ticks;
#ifdef PROC_atmega48
ISR(TIMER2_COMPA_vect) {
timer_ticks++;
}
#else
ISR(TIMER2_COMP_vect) {
timer_ticks++;
}
#endif
int main(void) {
volatile int tmp;
TCNT2 = 0; /* Timer 2 by CLK/64 */
#ifdef PROC_atmega48
OCR2A = 124; /* 2ms on 4MHz, CTC mode */
TCCR2A = 0x40 + 0x02; /* comA = 1, wgm=2 */
TCCR2B = 0x04; /* cs=4 */
DDRB = 0x08; /* PB3=out */
TIMSK2 = _BV(OCIE2A);
#else
OCR2 = 124; /* 2ms on 4MHz, CTC mode */
TCCR2 = 0x08 + 0x03 + 0x10; /* wgm=2, cs=3, com=1 */
DDRB = 0x80; /* PB7=out */
TIMSK = _BV(OCIE2);
#endif
sei();
tmp = timer_ticks;
while(1) {
if(tmp != timer_ticks) {
tmp = timer_ticks;
}
}
return 0;
}
/* EOF */
|
