Started following some tutorial on att85 usi. Downloaded example code from make avr book.

Make AVR Examples/Chapter10_Pulse-Width-Modulation/pwmTimers/pwmTimers.c

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+                       /* PWM Demo with serial control over three LEDs */
+
+// ------- Preamble -------- //
+#include <avr/io.h>                        /* Defines pins, ports, etc */
+#include <util/delay.h>                     /* Functions to waste time */
+#include "pinDefines.h"
+#include "USART.h"
+
+static inline void initTimers(void) {
+  // Timer 1 A,B
+  TCCR1A |= (1 << WGM10);                      /* Fast PWM mode, 8-bit */
+  TCCR1B |= (1 << WGM12);                       /* Fast PWM mode, pt.2 */
+  TCCR1B |= (1 << CS11);                     /* PWM Freq = F_CPU/8/256 */
+  TCCR1A |= (1 << COM1A1);                      /* PWM output on OCR1A */
+  TCCR1A |= (1 << COM1B1);                      /* PWM output on OCR1B */
+
+  // Timer 2
+  TCCR2A |= (1 << WGM20);                             /* Fast PWM mode */
+  TCCR2A |= (1 << WGM21);                       /* Fast PWM mode, pt.2 */
+  TCCR2B |= (1 << CS21);                     /* PWM Freq = F_CPU/8/256 */
+  TCCR2A |= (1 << COM2A1);                      /* PWM output on OCR2A */
+}
+
+int main(void) {
+
+  uint8_t brightness;
+
+  // -------- Inits --------- //
+
+  initTimers();
+  initUSART();
+  printString("-- LED PWM Demo --\r\n");
+
+               /* enable output on LED pins, triggered by PWM hardware */
+  LED_DDR |= (1 << LED1);
+  LED_DDR |= (1 << LED2);
+  LED_DDR |= (1 << LED3);
+
+  // ------ Event loop ------ //
+  while (1) {
+
+    printString("\r\nEnter (0-255) for PWM duty cycle: ");
+    brightness = getNumber();
+    OCR2A = OCR1B;
+    OCR1B = OCR1A;
+    OCR1A = brightness;
+
+  }                                                  /* End event loop */
+  return 0;                            /* This line is never reached */
+}