Add timer interrupt + PWM work

PWM-generator/main.c

@@ -0,0 +1,33 @@
+#include <avr/io.h>
+
+int main(void) {
+    // 1. Set PB1 (OC1A) as output
+    DDRB |= (1 << PB1);
+
+    // 2. Fast PWM mode (WGM13:0 = 14)
+    TCCR1A = (1 << COM1A1) | (1 << WGM11);
+    TCCR1B = (1 << WGM12) | (1 << WGM13);
+
+    // 3. Prescaler = 8 (start timer)
+    TCCR1B |= (1 << CS11);
+
+    // 4. Set TOP value (frequency)
+    ICR1 = 19999;   // ~50 Hz (good for visible LED dimming demo)
+
+    // 5. Initial duty cycle
+    OCR1A = 0;
+
+    while (1) {
+        // Increase brightness
+        for (uint16_t i = 0; i < 2000; i++) {
+            OCR1A = i * 10;   // increase duty
+            for (volatile uint32_t d = 0; d < 5000; d++); // small delay
+        }
+
+        // Decrease brightness
+        for (int16_t i = 2000; i > 0; i--) {
+            OCR1A = i * 10;
+            for (volatile uint32_t d = 0; d < 5000; d++);
+        }
+    }
+}