CVAVR Code:

using atmega128 (clock 16Mhz), usart0 (9600 baud rate), timer1 (scale clock 1024), adc.

formula timer1 when use clock freq 16Mhz

Ttimer1 = Periode Timer1

TCNT1 = Register Timer1

N = Scale clock (1, 8, 64, 256 dan 1024)

Tosc = Periode clock

Fosc = Frekuensi clock cristal

Tosc = 1/Fosc

Tosc = 1/16Mhz = 0,0000000625

Ttimer1 = Tosc * (65536 - TCNT1) * N

1 (second) = 0,0000000625 * (65536 - TCNT1) * 1024

TCNT1 = 49911

TCNT1 = C2F7 (in hex) <-- this use in //Timer 1 overflow interrupt service routine

Clock value = Fosc/N

Clock value = 16Mhz/1024 = 15,625 kHz <-- this use in clock value timer1

Can use timer0 or other timer with each formula

/*****************************************************

Chip type

: ATmega128

Program type

: Application

Clock frequency

: 16,000000 MHz

Memory model

: Small

External SRAM size

: 0

Data Stack size

: 1024

*****************************************************/

int sec, band, freq[7], i;

unsigned long int time_a, time_b;

int stat = 0;

#include <mega128.h>

#include <stdio.h>