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PWMFrequency.h
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//
// -----------------------
// PWM FREQUENCY PRESCALER
// -----------------------
// Written by Kiwisincebirth 2014
// Revised by MacTester57 (aka TheDIYGuy999) to allow correct PWM frequencies (confirmed with oscilloscope). January 2015
// - prescale variable: replaced uint8_t with uint16_t data type (fixes bug, which did not allow frequencies < 492Hz)
// - mode variable: replaced hex format with binary to make it more readable, if compared with bit tables in the 32U4 manual
// - added comments
// Revised by arufl
// - added ATMega 4809 support
//
#ifndef PWMFrequency
#define PWMFrequency
#if ARDUINO >= 100
#include <Arduino.h> // Arduino 1.0
#else
#include <WProgram.h> // Arduino 0022
#endif
#if defined __AVR_ATmega32U4__
/**
* Divides a given PWM pin frequency by a divisor.
*
* Arduino Leonardo AtMega 32u4 specific
*
* Sets the Prescaler (Divisor) for a given PWM pin. The resulting frequency
* is equal to the base frequency divided by the given divisor:
* - Base frequencies:
* o The base frequency for pins 3 and 11 is 64,500 Hz.
* o The base frequency for pins 5,6,9,10,13 is 31,250 Hz.
* - Divisors:
* o The divisors available on pins 3, 5, 9, 10 and 11 are: 1, 8, 64, 256, and 1024.
* o The divisors available on pins 6 and 13 are all powers of two between 1 and 16384
*
* PWM frequencies are tied together in pairs of pins. If one in a
* pair is changed, the other is also changed to match:
* - Pins 3 and 11 are paired on timer0 8bit (Default prescale=64, Freq=977Hz)
* - Pins 9 and 10 are paired on timer1 16bit (Default prescale=64, Freq=490Hz)
* - Pins 5 is exclusivly on timer3 16bit (Default prescale=64, Freq=490Hz)
* - Pins 6 and 13 are paired on timer4 10bit (default prescale=64, Freq=490Hz)
*
* Note: Pins 3 and 11 operate on Timer 0 changes this pins will
* affect the user of the main time millis() functions
*
* Thanks to MacTester of the TonyMacX86 forums for his work in defining
* the timings and testing this library
*/
void setPWMPrescaler(uint8_t pin, uint16_t prescale)
{
byte mode;
if(pin==3 || pin==5 || pin==9 || pin==10 || pin==11) {
switch(prescale) {
case 1: mode = 0b001; break;
case 8: mode = 0b010; break;
case 64: mode = 0b011; break;
case 256: mode = 0b100; break;
case 1024: mode = 0b101; break;
default: return;
}
} else if(pin==6 || pin==13) {
switch(prescale) {
case 1: mode = 0b0001; break;
case 2: mode = 0b0010; break;
case 4: mode = 0b0011; break;
case 8: mode = 0b0100; break;
case 16: mode = 0b0101; break;
case 32: mode = 0b0110; break;
case 64: mode = 0b0111; break;
case 128: mode = 0b1000; break;
case 256: mode = 0b1001; break;
case 512: mode = 0b1010; break;
case 1024: mode = 0b1011; break;
case 2048: mode = 0b1100; break;
case 4096: mode = 0b1101; break;
case 8192: mode = 0b1110; break;
case 16384: mode = 0b1111; break;
default: return;
}
}
if(pin==3 || pin==11) {
TCCR0B = TCCR1B & 0b11111000 | mode;
} else if (pin==9 || pin==10) {
TCCR1B = TCCR1B & 0b11111000 | mode;
} else if (pin==5) {
TCCR3B = TCCR3B & 0b11111000 | mode;
} else if (pin==6 || pin==13) {
TCCR4B = TCCR4B & 0b11110000 | mode;
}
}
#elseif defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
/**
* Divides a given PWM pin frequency by a divisor.
*
* Sets the Prescaler (Divisor) for a given PWM pin. The resulting frequency
* is equal to the base frequency divided by the given divisor:
* - Base frequencies:
* o The base frequency for pins 5 and 6 is 62500 Hz.
* o The base frequency for pins 3, 9, 10, and 11 is 31250 Hz.
* - Divisors:
* o The divisors available on pins 5, 6, 9, 10 are: 1,8,64,256,1024.
* o The divisors available on pins 3, 11 are: 1,8,32,64,128,256,1024.
*
* PWM frequencies are tied together in pairs of pins. If one in a
* pair is changed, the other is also changed to match:
* - Pins 5 and 6 are paired on timer0 (Default prescale=64, Freq=977Hz)
* - Pins 9 and 10 are paired on timer1 (Default prescale=64, Freq=490Hz)
* - Pins 3 and 11 are paired on timer2 (Default prescale=64, Freq=490Hz)
*
* Note that this function will have side effects on anything else
* that uses timers:
* - Changes on pins 5, or 6 may cause the delay() and
* millis() functions to stop working. Other timing-related
* functions may also be affected.
* - Changes on pins 9 or 10 will cause the Servo library to function
* incorrectly.
*
* Thanks to macegr of the Arduino forums for his documentation of the
* PWM frequency divisors. His post can be viewed at:
*
* http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1235060559/0#4
*/
void setPWMPrescaler(uint8_t pin, uint16_t prescale) {
byte mode;
if(pin == 5 || pin == 6 || pin == 9 || pin == 10) {
switch(prescale) {
case 1: mode = 0b001; break;
case 8: mode = 0b010; break;
case 64: mode = 0b011; break;
case 256: mode = 0b100; break;
case 1024: mode = 0b101; break;
default: return;
}
} else if(pin == 3 || pin == 11) {
switch(prescale) {
case 1: mode = 0b001; break;
case 8: mode = 0b010; break;
case 32: mode = 0b011; break;
case 64: mode = 0b100; break;
case 128: mode = 0b101; break;
case 256: mode = 0b110; break;
case 1024: mode = 0b111; break;
default: return;
}
}
if(pin==5 || pin==6) {
TCCR0B = TCCR0B & 0b11111000 | mode;
} else if (pin==9 || pin==10) {
TCCR1B = TCCR1B & 0b11111000 | mode;
} else if (pin==3 || pin==11) {
TCCR2B = TCCR2B & 0b11111000 | mode;
}
}
#else
/**
* Divides a given PWM pin frequency by a divisor.
* Arduino Nano Every (ATMega4809) specific by arufl
*
* Sets the Prescaler (Divisor) for a given PWM pin. The resulting frequency
* is equal to the base frequency divided by the given divisor:
* - Base frequencies:
* o The base frequency for all pins is 62500 Hz.
*
* - Divisors:
* o The divisors for pins 5,9 and 10 available are: 1,2,4,8,16,64,256,1024.
* o The divisors for pins 3 and 6: 1,2 and TCA0's divisor in use
*
*
* Note that this function will have side effects on anything else
* that uses timers:
* - Changes on pins 5,9 and 10 may cause the delay() and
* millis() functions to stop working. Other timing-related
* functions may also be affected.
*
* Thanks to plymdiver of the Arduino forums for his explaination on how the
* ATmega4809 timers works and which timer His post can be viewed at:
*
* https://forum.arduino.cc/index.php?topic=626736.msg4503396#msg4503396
*
*/
void setPWMPrescaler(uint8_t pin, uint16_t prescale) {
byte mode;
if(pin == 5 || pin == 9 || pin == 10) {
TCA0.SINGLE.CTRLA &= ~TCA_SINGLE_ENABLE_bm;
TCA0.SINGLE.CTRLA &= ~TCA_SINGLE_CLKSEL_gm;
switch(prescale) {
case 1: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV1_gc; break;
case 2: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV2_gc; break;
case 4: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV4_gc; break;
case 8: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV8_gc; break;
case 16: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV16_gc; break;
case 64: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV64_gc; break;
case 256: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV256_gc; break;
case 1024: TCA0.SINGLE.CTRLA |= TCA_SINGLE_CLKSEL_DIV1024_gc; break;
default: return;
}
TCA0.SINGLE.CTRLA |= TCA_SINGLE_ENABLE_bm;
}
if(pin == 6) {
TCB0_CTRLA &= ~TCB_ENABLE_bm;
TCB0_CTRLA &= ~TCB_CLKSEL_gm;
switch(prescale) {
case 1: TCB0_CTRLA |= TCB_CLKSEL_CLKDIV1_gc; break;
case 2: TCB0_CTRLA |= TCB_CLKSEL_CLKDIV2_gc; break;
case 64: TCB0_CTRLA |= TCB_CLKSEL_CLKTCA_gc; break;
default: return;
}
TCB0_CTRLA |= TCB_ENABLE_bm;
}
if(pin == 3) {
TCB1_CTRLA &= ~TCB_ENABLE_bm;
TCB1_CTRLA &= ~TCB_CLKSEL_gm;
switch(prescale) {
case 1: TCB1_CTRLA |= TCB_CLKSEL_CLKDIV1_gc; break;
case 2: TCB1_CTRLA |= TCB_CLKSEL_CLKDIV2_gc; break;
case 64: TCB1_CTRLA |= TCB_CLKSEL_CLKTCA_gc; break;
default: return;
}
TCB1_CTRLA |= TCB_ENABLE_bm;
}
}
#endif
#endif