Add timer interrupt + PWM work

Timer-Interrupt/main.c

@@ -0,0 +1,39 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <stdint.h>
+
+volatile uint32_t ms = 0;
+
+void timer1_init(void) {
+    TCCR1A = 0;
+    TCCR1B = 0;
+    TCNT1  = 0;
+
+    TCCR1B |= (1 << WGM12);
+    OCR1A = 249;
+    TIMSK1 |= (1 << OCIE1A);
+    TCCR1B |= (1 << CS11) | (1 << CS10);
+    sei();
+}
+
+ISR(TIMER1_COMPA_vect) {
+    ms++;
+}
+
+void delay_ms(uint32_t delay){
+    uint32_t start = ms;
+    while ((ms - start) < delay) {
+    }
+}
+
+int main(void) {
+    DDRC |= (1<<PC0);
+    timer1_init();
+
+    while(1) {
+        PORTC |= (1<<PC0);
+        delay_ms(500);
+        PORTC &= ~(1<<PC0);
+        delay_ms(500);
+    }
+}