tone_generator.cpp

#include "Arduino.h"
#include "tone_generator.h"
#include "definitions.h"

/*
 * SQUARE WAVE SIGNAL GENERATION
 *
 * baud_adj lets you to adjust or fine tune overall baud rate
 * by simultaneously adjust the 1200 Hz and 2400 Hz tone,
 * so that both tone would scales synchronously.
 * adj_1200 determined the 1200 hz tone adjustment.
 * tc1200 is the half of the 1200 Hz signal periods.
 *
 *      -------------------------                           -------
 *     |                         |                         |
 *     |                         |                         |
 *     |                         |                         |
 * ----                           -------------------------
 *
 *     |<------ tc1200 --------->|<------ tc1200 --------->|
 *
 * adj_2400 determined the 2400 hz tone adjustment.
 * tc2400 is the half of the 2400 Hz signal periods.
 *
 *      ------------              ------------              -------
 *     |            |            |            |            |
 *     |            |            |            |            |
 *     |            |            |            |            |
 * ----              ------------              ------------
 *
 *     |<--tc2400-->|<--tc2400-->|<--tc2400-->|<--tc2400-->|
 *
 */

const float baud_adj = 0.975;
const float adj_1200 = 1.0 * baud_adj;
const float adj_2400 = 1.0 * baud_adj;
unsigned int tc1200 = (unsigned int)(0.5 * adj_1200 * 1000000.0 / 1200.0);
unsigned int tc2400 = (unsigned int)(0.5 * adj_2400 * 1000000.0 / 2400.0);



void set_toneValue_1200() {
  digitalWrite(OUT_PIN, HIGH);
  delayMicroseconds(tc1200);
  digitalWrite(OUT_PIN, LOW);
  delayMicroseconds(tc1200);
}

void set_toneValue_2400() {
  digitalWrite(OUT_PIN, HIGH);
  delayMicroseconds(tc2400);
  digitalWrite(OUT_PIN, LOW);
  delayMicroseconds(tc2400);

  digitalWrite(OUT_PIN, HIGH);
  delayMicroseconds(tc2400);
  digitalWrite(OUT_PIN, LOW);
  delayMicroseconds(tc2400);
}

void set_toneValue(bool toneValue) {
  if (toneValue)
    set_toneValue_1200();
  else
    set_toneValue_2400();
}