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Copy pathTone.cpp
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205 lines (158 loc) · 5.44 KB
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/*
Copyright (c) 2015 Arduino LLC. All right reserved.
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 "variant.h"
#define WAIT_TC16_REGS_SYNC(x) while(x->COUNT16.STATUS.bit.SYNCBUSY);
uint32_t toneMaxFrequency = F_CPU / 2;
uint32_t lastOutputPin = 0xFFFFFFFF;
volatile uint32_t *portToggleRegister;
volatile uint32_t *portClearRegister;
volatile uint32_t portBitMask;
volatile int64_t toggleCount;
volatile bool toneIsActive = false;
volatile bool firstTimeRunning = false;
#define TONE_TC TC5
#define TONE_TC_IRQn TC5_IRQn
#define TONE_TC_TOP 0xFFFF
#define TONE_TC_CHANNEL 0
void TC5_Handler (void) __attribute__ ((weak, alias("Tone_Handler")));
static inline void resetTC (Tc* TCx)
{
// Disable TCx
TCx->COUNT16.CTRLA.reg &= ~TC_CTRLA_ENABLE;
WAIT_TC16_REGS_SYNC(TCx)
// Reset TCx
TCx->COUNT16.CTRLA.reg = TC_CTRLA_SWRST;
WAIT_TC16_REGS_SYNC(TCx)
while (TCx->COUNT16.CTRLA.bit.SWRST);
}
void toneAccurateClock (uint32_t accurateSystemCoreClockFrequency)
{
toneMaxFrequency = accurateSystemCoreClockFrequency / 2;
}
void tone (unsigned char outputPin, unsigned int frequency, unsigned long duration)
{
// Avoid divide by zero error by calling 'noTone' instead
if (frequency == 0)
{
noTone(outputPin);
return;
}
// Configure interrupt request
NVIC_DisableIRQ(TONE_TC_IRQn);
NVIC_ClearPendingIRQ(TONE_TC_IRQn);
if(!firstTimeRunning)
{
firstTimeRunning = true;
NVIC_SetPriority(TONE_TC_IRQn, 0);
// Enable GCLK for TC4 and TC5 (timer counter input clock)
GCLK->CLKCTRL.reg = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TC4_TC5));
while (GCLK->STATUS.bit.SYNCBUSY);
}
if (toneIsActive && (outputPin != lastOutputPin))
noTone(lastOutputPin);
//
// Calculate best prescaler divider and comparator value for a 16 bit TC peripheral
//
uint32_t prescalerConfigBits;
uint32_t ccValue;
ccValue = toneMaxFrequency / frequency - 1;
prescalerConfigBits = TC_CTRLA_PRESCALER_DIV1;
uint8_t i = 0;
while(ccValue > TONE_TC_TOP)
{
ccValue = toneMaxFrequency / frequency / (2<<i) - 1;
i++;
if(i == 4 || i == 6 || i == 8) //DIV32 DIV128 and DIV512 are not available
i++;
}
switch(i-1)
{
case 0: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV2; break;
case 1: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV4; break;
case 2: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV8; break;
case 3: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV16; break;
case 5: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV64; break;
case 7: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV256; break;
case 9: prescalerConfigBits = TC_CTRLA_PRESCALER_DIV1024; break;
default: break;
}
toggleCount = (duration > 0 ? frequency * duration * 2 / 1000UL : -1LL);
resetTC(TONE_TC);
uint16_t tmpReg = 0;
tmpReg |= TC_CTRLA_MODE_COUNT16; // Set Timer counter Mode to 16 bits
tmpReg |= TC_CTRLA_WAVEGEN_MFRQ; // Set TONE_TC mode as match frequency
tmpReg |= prescalerConfigBits;
TONE_TC->COUNT16.CTRLA.reg |= tmpReg;
WAIT_TC16_REGS_SYNC(TONE_TC)
TONE_TC->COUNT16.CC[TONE_TC_CHANNEL].reg = (uint16_t) ccValue;
WAIT_TC16_REGS_SYNC(TONE_TC)
portToggleRegister = &(PORT->Group[g_APinDescription[outputPin].ulPort].OUTTGL.reg);
portClearRegister = &(PORT->Group[g_APinDescription[outputPin].ulPort].OUTCLR.reg);
portBitMask = (1ul << g_APinDescription[outputPin].ulPin);
// Enable the TONE_TC interrupt request
TONE_TC->COUNT16.INTENSET.bit.MC0 = 1;
if (outputPin != lastOutputPin)
{
lastOutputPin = outputPin;
digitalWrite(outputPin, LOW);
pinMode(outputPin, OUTPUT);
toneIsActive = true;
}
// Enable TONE_TC
TONE_TC->COUNT16.CTRLA.reg |= TC_CTRLA_ENABLE;
WAIT_TC16_REGS_SYNC(TONE_TC)
NVIC_EnableIRQ(TONE_TC_IRQn);
}
void noTone (uint8_t outputPin)
{
/* 'tone' need to run at least once in order to enable GCLK for
* the timers used for the tone-functionality. If 'noTone' is called
* without ever calling 'tone' before then 'WAIT_TC16_REGS_SYNC(TCx)'
* will wait infinitely. The variable 'firstTimeRunning' is set the
* 1st time 'tone' is set so it can be used to detect wether or not
* 'tone' has been called before.
*/
if(firstTimeRunning)
{
resetTC(TONE_TC);
digitalWrite(outputPin, LOW);
toneIsActive = false;
}
}
#ifdef __cplusplus
extern "C" {
#endif
void Tone_Handler (void)
{
if (toggleCount != 0)
{
// Toggle the ouput pin
*portToggleRegister = portBitMask;
if (toggleCount > 0)
--toggleCount;
// Clear the interrupt
TONE_TC->COUNT16.INTFLAG.bit.MC0 = 1;
}
else
{
resetTC(TONE_TC);
*portClearRegister = portBitMask;
toneIsActive = false;
}
}
#ifdef __cplusplus
}
#endif