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

Make AVR Examples/Chapter09_Introduction-to-Timer-Counter-Hardware/amRadio/amRadio.c

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+/*
+Plays a simple tune, broadcasts it in the AM radio band.
+*/
+
+// ------- Preamble -------- //
+#include <avr/io.h>                        /* Defines pins, ports, etc */
+#include <util/delay.h>                     /* Functions to waste time */
+#include <avr/power.h>
+#include <avr/interrupt.h>
+#include "pinDefines.h"
+#include "scale16.h"
+
+#define COUNTER_VALUE   3              /* determines carrier frequency */
+
+// From f = f_cpu / ( 2* N* (1 + OCRnx) )
+// Good values for the AM band from 2 to 6: pick one that's clear
+// Divide by two b/c we're toggling on or off each loop;
+//  a full cycle of the carrier takes two loops.
+// 8Mhz / (2 * 1 * (1+2)) = 1333 kHz
+// 8Mhz / (2 * 1 * (1+3)) = 1000 kHz
+// 8Mhz / (2 * 1 * (1+4)) = 800 kHz
+// 8Mhz / (2 * 1 * (1+5)) = 670 kHz
+// 8Mhz / (2 * 1 * (1+6)) = 570 kHz
+// 8Mhz / (2 * 1 * (1+7)) = 500 kHz
+
+static inline void initTimer0(void) {
+  TCCR0A |= (1 << WGM01);                                  /* CTC mode */
+  TCCR0A |= (1 << COM0B0);            /* Toggles pin each time through */
+  TCCR0B |= (1 << CS00);              /* Clock at CPU frequency, ~8MHz */
+  OCR0A = COUNTER_VALUE;                          /* carrier frequency */
+}
+
+static inline void initTimer1(void) {
+  TCCR1B |= (1 << WGM12);                                  /* CTC mode */
+  TCCR1B |= (1 << CS11);            /* Clock at CPU/8 frequency, ~1MHz */
+  TIMSK1 |= (1 << OCIE1A);          /* enable output compare interrupt */
+}
+
+ISR(TIMER1_COMPA_vect) {                 /* ISR for audio-rate Timer 1 */
+  ANTENNA_DDR ^= (1 << ANTENNA);          /* toggle carrier on and off */
+}
+
+static inline void transmitBeep(uint16_t pitch, uint16_t duration) {
+  OCR1A = pitch;                               /* set pitch for timer1 */
+  sei();                                         /* turn on interrupts */
+  do {
+    _delay_ms(1);                            /* delay for pitch cycles */
+    duration--;
+  } while (duration > 0);
+  cli();                  /* and disable ISR so that it stops toggling */
+  ANTENNA_DDR |= (1 << ANTENNA);               /* back on full carrier */
+}
+
+int main(void) {
+  // -------- Inits --------- //
+
+  clock_prescale_set(clock_div_1);                  /* CPU clock 8 MHz */
+  initTimer0();
+  initTimer1();
+
+  // ------ Event loop ------ //
+  while (1) {
+
+    transmitBeep(E3, 200);
+    _delay_ms(100);
+    transmitBeep(E3, 200);
+    _delay_ms(200);
+    transmitBeep(E3, 200);
+    _delay_ms(200);
+    transmitBeep(C3, 200);
+    transmitBeep(E3, 200);
+    _delay_ms(200);
+    transmitBeep(G3, 400);
+    _delay_ms(500);
+    transmitBeep(G2, 400);
+
+    _delay_ms(2500);
+
+  }                                                  /* End event loop */
+  return 0;                            /* This line is never reached */
+}