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

2022-09-20 01:08:01 -04:00
parent d0cbc0000e
commit 361a828c46
295 changed files with 68746 additions and 0 deletions
--- a/Examples/Chapter09_Introduction-to-Timer-Counter-Hardware/timerAudio/timerAudio.c
+++ b/Examples/Chapter09_Introduction-to-Timer-Counter-Hardware/timerAudio/timerAudio.c
@@ -0,0 +1,49 @@
+/*
+
+Quick audio demo using Timer 0 to generate audio frequencies directly.
+
+*/
+
+// ------- Preamble -------- //
+#include <avr/io.h>                        /* Defines pins, ports, etc */
+#include <util/delay.h>                     /* Functions to waste time */
+#include "pinDefines.h"
+#include "scale8.h"                                     /* 8-bit scale */
+
+static inline void initTimer(void) {
+  TCCR0A |= (1 << WGM01);                                  /* CTC mode */
+  TCCR0A |= (1 << COM0A0);           /* Toggles pin each cycle through */
+  TCCR0B |= (1 << CS00) | (1 << CS01);               /* CPU clock / 64 */
+}
+
+static inline void playNote(uint8_t period, uint16_t duration) {
+
+  TCNT0 = 0;                                      /* reset the counter */
+  OCR0A = period;                                     /* set pitch */
+  SPEAKER_DDR |= (1 << SPEAKER);           /* enable output on speaker */
+
+  while (duration) {                                 /* Variable delay */
+    _delay_ms(1);
+    duration--;
+  }
+  SPEAKER_DDR &= ~(1 << SPEAKER);                  /* turn speaker off */
+}
+
+int main(void) {
+  // -------- Inits --------- //
+  initTimer();
+  // ------ Event loop ------ //
+  while (1) {
+                                                    /* Play some notes */
+    playNote(C2, 200);
+    playNote(E2, 200);
+    playNote(G2, 200);
+    playNote(C3, 400);
+
+    _delay_ms(1000);
+    _delay_ms(1000);
+    _delay_ms(1000);
+
+  }                                                  /* End event loop */
+  return 0;                            /* This line is never reached */
+}