Cores:Tone.cpp
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Tone.cpp
/* Tone.cpp
A Tone Generator Library
Written by Brett Hagman
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
Version Modified By Date Comments
------- ----------- -------- --------
0001 B Hagman 09/08/02 Initial coding
0002 B Hagman 09/08/18 Multiple pins
0003 B Hagman 09/08/18 Moved initialization from constructor to begin()
0004 B Hagman 09/09/26 Fixed problems with ATmega8
0005 B Hagman 09/11/23 Scanned prescalars for best fit on 8 bit timers
09/11/25 Changed pin toggle method to XOR
09/11/25 Fixed timer0 from being excluded
0006 D Mellis 09/12/29 Replaced objects with functions
0007 M Sproul 10/08/29 Changed #ifdefs from cpu to register
0008 S Kanemoto 12/06/22 Fixed for Leonardo by @maris_HY
0009 J Reucker 15/04/10 Issue #292 Fixed problems with ATmega8 (thanks to Pete62)
0010 jipp 15/04/13 added additional define check #2923
*************************************************/
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "Arduino.h"
#include "pins_arduino.h"
#if defined(__AVR_ATmega8__) || defined(__AVR_ATmega128__)
#define TCCR2A TCCR2
#define TCCR2B TCCR2
#define COM2A1 COM21
#define COM2A0 COM20
#define OCR2A OCR2
#define TIMSK2 TIMSK
#define OCIE2A OCIE2
#define TIMER2_COMPA_vect TIMER2_COMP_vect
#define TIMSK1 TIMSK
#endif
// timerx_toggle_count:
// > 0 - duration specified
// = 0 - stopped
// < 0 - infinitely (until stop() method called, or new play() called)
#if !defined(__AVR_ATmega8__)
volatile long timer0_toggle_count;
volatile uint8_t *timer0_pin_port;
volatile uint8_t timer0_pin_mask;
#endif
volatile long timer1_toggle_count;
volatile uint8_t *timer1_pin_port;
volatile uint8_t timer1_pin_mask;
volatile long timer2_toggle_count;
volatile uint8_t *timer2_pin_port;
volatile uint8_t timer2_pin_mask;
#if defined(TIMSK3)
volatile long timer3_toggle_count;
volatile uint8_t *timer3_pin_port;
volatile uint8_t timer3_pin_mask;
#endif
#if defined(TIMSK4)
volatile long timer4_toggle_count;
volatile uint8_t *timer4_pin_port;
volatile uint8_t timer4_pin_mask;
#endif
#if defined(TIMSK5)
volatile long timer5_toggle_count;
volatile uint8_t *timer5_pin_port;
volatile uint8_t timer5_pin_mask;
#endif
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
#define AVAILABLE_TONE_PINS 1
#define USE_TIMER2
const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 3, 4, 5, 1, 0 */ };
static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255, 255, 255, 255, 255 */ };
#elif defined(__AVR_ATmega8__)
#define AVAILABLE_TONE_PINS 1
#define USE_TIMER2
const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 1 */ };
static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255 */ };
#elif defined(__AVR_ATmega32U4__)
#define AVAILABLE_TONE_PINS 1
#define USE_TIMER3
const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 3 /*, 1 */ };
static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255 */ };
#else
#define AVAILABLE_TONE_PINS 1
#define USE_TIMER2
// Leave timer 0 to last.
const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 1, 0 */ };
static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255, 255 */ };
#endif
static int8_t toneBegin(uint8_t _pin)
{
int8_t _timer = -1;
// if we're already using the pin, the timer should be configured.
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == _pin) {
return pgm_read_byte(tone_pin_to_timer_PGM + i);
}
}
// search for an unused timer.
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == 255) {
tone_pins[i] = _pin;
_timer = pgm_read_byte(tone_pin_to_timer_PGM + i);
break;
}
}
if (_timer != -1)
{
// Set timer specific stuff
// All timers in CTC mode
// 8 bit timers will require changing prescalar values,
// whereas 16 bit timers are set to either ck/1 or ck/64 prescalar
switch (_timer)
{
#if defined(TCCR0A) && defined(TCCR0B) && defined(WGM01)
case 0:
// 8 bit timer
TCCR0A = 0;
TCCR0B = 0;
bitWrite(TCCR0A, WGM01, 1);
bitWrite(TCCR0B, CS00, 1);
timer0_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer0_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
#if defined(TCCR1A) && defined(TCCR1B) && defined(WGM12)
case 1:
// 16 bit timer
TCCR1A = 0;
TCCR1B = 0;
bitWrite(TCCR1B, WGM12, 1);
bitWrite(TCCR1B, CS10, 1);
timer1_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer1_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
#if defined(TCCR2A) && defined(TCCR2B)
case 2:
// 8 bit timer
TCCR2A = 0;
TCCR2B = 0;
bitWrite(TCCR2A, WGM21, 1);
bitWrite(TCCR2B, CS20, 1);
timer2_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer2_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
#if defined(TCCR3A) && defined(TCCR3B) && defined(TIMSK3)
case 3:
// 16 bit timer
TCCR3A = 0;
TCCR3B = 0;
bitWrite(TCCR3B, WGM32, 1);
bitWrite(TCCR3B, CS30, 1);
timer3_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer3_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
#if defined(TCCR4A) && defined(TCCR4B) && defined(TIMSK4)
case 4:
// 16 bit timer
TCCR4A = 0;
TCCR4B = 0;
#if defined(WGM42)
bitWrite(TCCR4B, WGM42, 1);
#elif defined(CS43)
#warning this may not be correct
// atmega32u4
bitWrite(TCCR4B, CS43, 1);
#endif
bitWrite(TCCR4B, CS40, 1);
timer4_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer4_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
#if defined(TCCR5A) && defined(TCCR5B) && defined(TIMSK5)
case 5:
// 16 bit timer
TCCR5A = 0;
TCCR5B = 0;
bitWrite(TCCR5B, WGM52, 1);
bitWrite(TCCR5B, CS50, 1);
timer5_pin_port = portOutputRegister(digitalPinToPort(_pin));
timer5_pin_mask = digitalPinToBitMask(_pin);
break;
#endif
}
}
return _timer;
}
// frequency (in hertz) and duration (in milliseconds).
void tone(uint8_t _pin, unsigned int frequency, unsigned long duration)
{
uint8_t prescalarbits = 0b001;
long toggle_count = 0;
uint32_t ocr = 0;
int8_t _timer;
_timer = toneBegin(_pin);
if (_timer >= 0)
{
// Set the pinMode as OUTPUT
pinMode(_pin, OUTPUT);
// if we are using an 8 bit timer, scan through prescalars to find the best fit
if (_timer == 0 || _timer == 2)
{
ocr = F_CPU / frequency / 2 - 1;
prescalarbits = 0b001; // ck/1: same for both timers
if (ocr > 255)
{
ocr = F_CPU / frequency / 2 / 8 - 1;
prescalarbits = 0b010; // ck/8: same for both timers
if (_timer == 2 && ocr > 255)
{
ocr = F_CPU / frequency / 2 / 32 - 1;
prescalarbits = 0b011;
}
if (ocr > 255)
{
ocr = F_CPU / frequency / 2 / 64 - 1;
prescalarbits = _timer == 0 ? 0b011 : 0b100;
if (_timer == 2 && ocr > 255)
{
ocr = F_CPU / frequency / 2 / 128 - 1;
prescalarbits = 0b101;
}
if (ocr > 255)
{
ocr = F_CPU / frequency / 2 / 256 - 1;
prescalarbits = _timer == 0 ? 0b100 : 0b110;
if (ocr > 255)
{
// can't do any better than /1024
ocr = F_CPU / frequency / 2 / 1024 - 1;
prescalarbits = _timer == 0 ? 0b101 : 0b111;
}
}
}
}
#if defined(TCCR0B)
if (_timer == 0)
{
TCCR0B = (TCCR0B & 0b11111000) | prescalarbits;
}
else
#endif
#if defined(TCCR2B)
{
TCCR2B = (TCCR2B & 0b11111000) | prescalarbits;
}
#else
{
// dummy place holder to make the above ifdefs work
}
#endif
}
else
{
// two choices for the 16 bit timers: ck/1 or ck/64
ocr = F_CPU / frequency / 2 - 1;
prescalarbits = 0b001;
if (ocr > 0xffff)
{
ocr = F_CPU / frequency / 2 / 64 - 1;
prescalarbits = 0b011;
}
if (_timer == 1)
{
#if defined(TCCR1B)
TCCR1B = (TCCR1B & 0b11111000) | prescalarbits;
#endif
}
#if defined(TCCR3B)
else if (_timer == 3)
TCCR3B = (TCCR3B & 0b11111000) | prescalarbits;
#endif
#if defined(TCCR4B)
else if (_timer == 4)
TCCR4B = (TCCR4B & 0b11111000) | prescalarbits;
#endif
#if defined(TCCR5B)
else if (_timer == 5)
TCCR5B = (TCCR5B & 0b11111000) | prescalarbits;
#endif
}
// Calculate the toggle count
if (duration > 0)
{
toggle_count = 2 * frequency * duration / 1000;
}
else
{
toggle_count = -1;
}
// Set the OCR for the given timer,
// set the toggle count,
// then turn on the interrupts
switch (_timer)
{
#if defined(OCR0A) && defined(TIMSK0) && defined(OCIE0A)
case 0:
OCR0A = ocr;
timer0_toggle_count = toggle_count;
bitWrite(TIMSK0, OCIE0A, 1);
break;
#endif
case 1:
#if defined(OCR1A) && defined(TIMSK1) && defined(OCIE1A)
OCR1A = ocr;
timer1_toggle_count = toggle_count;
bitWrite(TIMSK1, OCIE1A, 1);
#elif defined(OCR1A) && defined(TIMSK) && defined(OCIE1A)
// this combination is for at least the ATmega32
OCR1A = ocr;
timer1_toggle_count = toggle_count;
bitWrite(TIMSK, OCIE1A, 1);
#endif
break;
#if defined(OCR2A) && defined(TIMSK2) && defined(OCIE2A)
case 2:
OCR2A = ocr;
timer2_toggle_count = toggle_count;
bitWrite(TIMSK2, OCIE2A, 1);
break;
#endif
#if defined(OCR3A) && defined(TIMSK3) && defined(OCIE3A)
case 3:
OCR3A = ocr;
timer3_toggle_count = toggle_count;
bitWrite(TIMSK3, OCIE3A, 1);
break;
#endif
#if defined(OCR4A) && defined(TIMSK4) && defined(OCIE4A)
case 4:
OCR4A = ocr;
timer4_toggle_count = toggle_count;
bitWrite(TIMSK4, OCIE4A, 1);
break;
#endif
#if defined(OCR5A) && defined(TIMSK5) && defined(OCIE5A)
case 5:
OCR5A = ocr;
timer5_toggle_count = toggle_count;
bitWrite(TIMSK5, OCIE5A, 1);
break;
#endif
}
}
}
// XXX: this function only works properly for timer 2 (the only one we use
// currently). for the others, it should end the tone, but won't restore
// proper PWM functionality for the timer.
void disableTimer(uint8_t _timer)
{
switch (_timer)
{
case 0:
#if defined(TIMSK0)
TIMSK0 = 0;
#elif defined(TIMSK)
TIMSK = 0; // atmega32
#endif
break;
#if defined(TIMSK1) && defined(OCIE1A)
case 1:
bitWrite(TIMSK1, OCIE1A, 0);
break;
#endif
case 2:
#if defined(TIMSK2) && defined(OCIE2A)
bitWrite(TIMSK2, OCIE2A, 0); // disable interrupt
#endif
#if defined(TCCR2A) && defined(WGM20)
TCCR2A = (1 << WGM20);
#endif
#if defined(TCCR2B) && defined(CS22)
TCCR2B = (TCCR2B & 0b11111000) | (1 << CS22);
#endif
#if defined(OCR2A)
OCR2A = 0;
#endif
break;
#if defined(TIMSK3) && defined(OCIE3A)
case 3:
bitWrite(TIMSK3, OCIE3A, 0);
break;
#endif
#if defined(TIMSK4) && defined(OCIE4A)
case 4:
bitWrite(TIMSK4, OCIE4A, 0);
break;
#endif
#if defined(TIMSK5) && defined(OCIE5A)
case 5:
bitWrite(TIMSK5, OCIE5A, 0);
break;
#endif
}
}
void noTone(uint8_t _pin)
{
int8_t _timer = -1;
for (int i = 0; i < AVAILABLE_TONE_PINS; i++) {
if (tone_pins[i] == _pin) {
_timer = pgm_read_byte(tone_pin_to_timer_PGM + i);
tone_pins[i] = 255;
}
}
disableTimer(_timer);
digitalWrite(_pin, 0);
}
#ifdef USE_TIMER0
ISR(TIMER0_COMPA_vect)
{
if (timer0_toggle_count != 0)
{
// toggle the pin
*timer0_pin_port ^= timer0_pin_mask;
if (timer0_toggle_count > 0)
timer0_toggle_count--;
}
else
{
disableTimer(0);
*timer0_pin_port &= ~(timer0_pin_mask); // keep pin low after stop
}
}
#endif
#ifdef USE_TIMER1
ISR(TIMER1_COMPA_vect)
{
if (timer1_toggle_count != 0)
{
// toggle the pin
*timer1_pin_port ^= timer1_pin_mask;
if (timer1_toggle_count > 0)
timer1_toggle_count--;
}
else
{
disableTimer(1);
*timer1_pin_port &= ~(timer1_pin_mask); // keep pin low after stop
}
}
#endif
#ifdef USE_TIMER2
ISR(TIMER2_COMPA_vect)
{
if (timer2_toggle_count != 0)
{
// toggle the pin
*timer2_pin_port ^= timer2_pin_mask;
if (timer2_toggle_count > 0)
timer2_toggle_count--;
}
else
{
// need to call noTone() so that the tone_pins[] entry is reset, so the
// timer gets initialized next time we call tone().
// XXX: this assumes timer 2 is always the first one used.
noTone(tone_pins[0]);
// disableTimer(2);
// *timer2_pin_port &= ~(timer2_pin_mask); // keep pin low after stop
}
}
#endif
#ifdef USE_TIMER3
ISR(TIMER3_COMPA_vect)
{
if (timer3_toggle_count != 0)
{
// toggle the pin
*timer3_pin_port ^= timer3_pin_mask;
if (timer3_toggle_count > 0)
timer3_toggle_count--;
}
else
{
disableTimer(3);
*timer3_pin_port &= ~(timer3_pin_mask); // keep pin low after stop
}
}
#endif
#ifdef USE_TIMER4
ISR(TIMER4_COMPA_vect)
{
if (timer4_toggle_count != 0)
{
// toggle the pin
*timer4_pin_port ^= timer4_pin_mask;
if (timer4_toggle_count > 0)
timer4_toggle_count--;
}
else
{
disableTimer(4);
*timer4_pin_port &= ~(timer4_pin_mask); // keep pin low after stop
}
}
#endif
#ifdef USE_TIMER5
ISR(TIMER5_COMPA_vect)
{
if (timer5_toggle_count != 0)
{
// toggle the pin
*timer5_pin_port ^= timer5_pin_mask;
if (timer5_toggle_count > 0)
timer5_toggle_count--;
}
else
{
disableTimer(5);
*timer5_pin_port &= ~(timer5_pin_mask); // keep pin low after stop
}
}
#endif
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