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esp8266/cores/esp8266/Tone.cpp
2016-02-05 12:03:29 +00:00

126 lines
3.0 KiB
C++

/*
Tone.cpp
A Tone Generator Library for the ESP8266
Copyright (c) 2016 Ben Pirt. All rights reserved.
This file is part of the esp8266 core for Arduino environment.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "Arduino.h"
#include "pins_arduino.h"
#define AVAILABLE_TONE_PINS 1
const uint8_t tone_timers[] = { 1 };
static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255, };
static long toggle_counts[AVAILABLE_TONE_PINS] = { 0, };
#define T1INDEX 0
void t1IntHandler();
static int8_t toneBegin(uint8_t _pin) {
int8_t _index = -1;
// if we're already using the pin, reuse it.
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == _pin) {
return i;
}
}
// search for an unused timer.
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == 255) {
tone_pins[i] = _pin;
_index = i;
break;
}
}
return _index;
}
// frequency (in hertz) and duration (in milliseconds).
void tone(uint8_t _pin, unsigned int frequency, unsigned long duration) {
int8_t _index;
_index = toneBegin(_pin);
if (_index >= 0) {
// Set the pinMode as OUTPUT
pinMode(_pin, OUTPUT);
// Calculate the toggle count
if (duration > 0) {
toggle_counts[_index] = 2 * frequency * duration / 1000;
} else {
toggle_counts[_index] = -1;
}
// set up the interrupt frequency
switch (tone_timers[_index]) {
case 0:
// Not currently supported
break;
case 1:
timer1_disable();
timer1_isr_init();
timer1_attachInterrupt(t1IntHandler);
timer1_enable(TIM_DIV1, TIM_EDGE, TIM_LOOP);
timer1_write((clockCyclesPerMicrosecond() * 500000) / frequency);
break;
}
}
}
void disableTimer(uint8_t _index) {
tone_pins[_index] = 255;
switch (tone_timers[_index]) {
case 0:
// Not currently supported
break;
case 1:
timer1_disable();
break;
}
}
void noTone(uint8_t _pin) {
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == _pin) {
tone_pins[i] = 255;
disableTimer(i);
break;
}
}
digitalWrite(_pin, LOW);
}
void t1IntHandler() {
if (toggle_counts[T1INDEX] > 0){
// toggle the pin
digitalWrite(tone_pins[T1INDEX], toggle_counts[T1INDEX] % 2);
toggle_counts[T1INDEX]--;
}else{
disableTimer(T1INDEX);
digitalWrite(tone_pins[T1INDEX], LOW);
}
}