57 lines
1.1 KiB
C
57 lines
1.1 KiB
C
/*
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* timer_t2_ms.c
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*
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* Created: 21/02/2021 13:20:32
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* Author : Etienne
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*/
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#define F_CPU 8e6
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#include <avr/io.h>
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#include <util/delay.h>
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#include <avr/interrupt.h>
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#define BIT(x) (1 << (x))
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// wait(): busy waiting for 'ms' millisecond
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// Used library: util/delay.h
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void wait( int ms ) {
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for (int tms=0; tms<ms; tms++) {
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_delay_ms( 1 ); // library function (max 30 ms at 8MHz)
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}
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}
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volatile int msCount = 0;
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void timer2Init( void ) {
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OCR2 = 155; // Compare value of counter 2
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TIMSK |= BIT(7); // T2 compare match interrupt enable
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sei(); // turn_on intr all
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TCCR2 = 0b00001011; // Initialize T2: timer, prescaler=32, compare output disconnected,CTC,RUN
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}
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unsigned int msThersh = 15;
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ISR( TIMER2_COMP_vect ) {
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msCount++; // Increment ms counter
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if ( msCount >= msThersh ) {
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// Toggle bit 0 van PORTC
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PORTC ^= BIT(0);
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msCount = 0;
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if(msThersh == 15){
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msThersh = 25;
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} else {
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msThersh = 15;
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} // Reset ms_count value
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}
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}
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int main( void ) {
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DDRC = 0xFF;
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PORTC = BIT(0); // set PORTC for output (toggle PC0)
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timer2Init();
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while (1) {
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// do something else
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wait(10); // every 10 ms (busy waiting
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}
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} |