opdracht 3.3

Microcontrollers/opdracht 3.3/main.c

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