initial avr projects (blink + interrupts)

interrupts/delay.h

@@ -0,0 +1,35 @@
+#ifndef DELAY_H
+#define DELAY_H
+
+#include <avr/io.h>
+#include <stdint.h>
+
+// Call this ONCE in main() before using delay_ms()
+static inline void timer1_init(void) {
+    // Configure Timer1 in CTC mode
+    TCCR1B |= (1 << WGM12);
+
+    // Set compare match for 1ms delay (16MHz / 64 prescaler)
+    OCR1A = 250;
+
+    // Start Timer1 with prescaler 64
+    TCCR1B |= (1 << CS11) | (1 << CS10);
+
+    // Reset timer count
+    TCNT1 = 0;
+}
+
+// Delay function assumes timer already initialized
+static inline void delay_ms(uint16_t ms) {
+    for (uint16_t i = 0; i < ms; i++) {
+        // Clear compare flag
+        TIFR1 |= (1 << OCF1A);
+
+        // Wait for compare match flag
+        while (!(TIFR1 & (1 << OCF1A))) {
+            // Busy wait
+        }
+    }
+}
+
+#endif // DELAY_H