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willem oldemans
2020-10-01 09:52:32 +02:00
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67
PMWFrequency/PWMFrequency.ino Normal file
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/*
Fade
This example shows how to fade an LED on pin 9
using the analogWrite() function.
The analogWrite() function uses PWM, so if
you want to change the pin you're using, be
sure to use another PWM capable pin. On most
Arduino, the PWM pins are identified with
a "~" sign, like ~3, ~5, ~6, ~9, ~10 and ~11.
This example code is in the public domain.
*/
//
// =======================================================================================================
// INCLUDE LIRBARIES
// =======================================================================================================
//
#include <PWMFrequency.h> // https://github.com/TheDIYGuy999/PWMFrequency
//
// =======================================================================================================
// PIN ASSIGNMENTS & GLOBAL VARIABLES
// =======================================================================================================
//
int led = 9; // the PWM pin the LED is attached to
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by
///
// =======================================================================================================
// MAIN ARDUINO SETUP (1x during startup)
// =======================================================================================================
//
void setup() {
// declare pin 9 to be an output:
pinMode(led, OUTPUT);
// PWM frequency: 32 = 984Hz (default), 8 = 3936Hz, 1 = 31488Hz
setPWMPrescaler(9, 1);
}
//
// =======================================================================================================
// MAIN LOOP
// =======================================================================================================
//
void loop() {
// set the brightness of pin 9:
analogWrite(led, brightness);
// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;
// reverse the direction of the fading at the ends of the fade:
if (brightness == 0 || brightness == 255) {
fadeAmount = -fadeAmount ;
}
// wait for 30 milliseconds to see the dimming effect
delay(30);
}

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PWMFrequency.cpp Normal file
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#include <Arduino.h>
#include "PWMFrequency.h"
void setPWMPrescaler(uint8_t pin, uint16_t prescale)
{
/**
* 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
*/
//byte mode;
#if defined __AVR_ATmega32U4__
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;
}
}
#elif defined (STM32F1xx)
//stm pwm config
#else
/**
* 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
*/
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;
}
#endif
}

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PWMFrequency.h Normal file
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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
//
#ifndef PWMFrequency
#define PWMFrequency
#if ARDUINO >= 100
#include <Arduino.h> // Arduino 1.0
#else
#include <WProgram.h> // Arduino 0022
#endif
void setPWMPrescaler(uint8_t pin, uint16_t prescale);
#endif

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README.md Normal file
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PWM Frequency Arduino Library
=============================
Library for Setting the PWM Frequency
Written by kiwisincebirth 2014
Please keep in mind that changing the PWM frequency changes the Atmega's timers and disrupts the normal operation of many functions that rely on time (delay(), millis(), Servo library).
This Library supports both ATMega 328 and 32U4 (Leonardo)
Example
=======
Here are some usage examples of the function:
// Set pin 9's PWM frequency to 3906 Hz (31250/8 = 3906)
// Note that the base frequency for pins 3, 9, 10, and 11 is 31250 Hz
setPwmFrequency(9, 8);
// Set pin 6's PWM frequency to 62500 Hz (62500/1 = 62500)
// Note that the base frequency for pins 5 and 6 is 62500 Hz
setPwmFrequency(6, 1);
// Set pin 10's PWM frequency to 31 Hz (31250/1024 = 31)
setPwmFrequency(10, 1024);
See
===
http://playground.arduino.cc/Code/PwmFrequency
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
Thanks to MacTester57 (aka TheDIYGuy999) for providing ATMega 32U4 testing
http://www.tonymacx86.com/imac-mods/107859-kiwis-next-project-imac-g5-10.html#post765116
Version History
===============
2.0 2014-07-30 Added Support for ATMega 32U4 Leonardo timers
Because it looks like, that this repo (https://github.com/kiwisincebirth/Arduino/tree/master/libraries/PWMFrequency) is not maintained anymore, I've cloned it.
The following changes were done by me, TheDIYGuy999:
New in V 2.1:
- Syntax coloration enhanced
- folder structure changed, so you can download and install it as usual

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keywords.txt Normal file
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#######################################
# Syntax Coloring Map LowPower
#######################################
#######################################
# Datatypes (KEYWORD1)
#######################################
PWMFrequency KEYWORD1
#######################################
# Methods and Functions (KEYWORD2)
#######################################
setPWMPrescaler KEYWORD2
#######################################
# Instances (KEYWORD2)
#######################################
#######################################
# Constants (LITERAL1)
#######################################