This sketch is used by Exercise: Adafruit PWM I2C Module.
Full Source Code
The main code is in Adafruit_PWM.ino.
/***************************************************
This is an example for our Adafruit 16-channel PWM & Servo driver
PWM test - this will drive 16 PWMs in a 'wave'
Pick one up today in the adafruit shop!
------> http://www.adafruit.com/products/815
These displays use I2C to communicate, 2 pins are required to
interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include <Wire.h>
// #include <Adafruit_PWMServoDriver.h>
#include "Adafruit_PWMServoDriver.h"
// called this way, it uses the default address 0x40
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
// you can also call it with a different address you want
//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);
void setup() {
Serial.begin(9600);
Serial.println("16 channel PWM test!");
// if you want to really speed stuff up, you can go into 'fast 400khz I2C' mode
// some i2c devices dont like this so much so if you're sharing the bus, watch
// out for this!
pwm.begin();
pwm.setPWMFreq(1600); // This is the maximum PWM frequency
// save I2C bitrate
uint8_t twbrbackup = TWBR;
// must be changed after calling Wire.begin() (inside pwm.begin())
TWBR = 12; // upgrade to 400KHz!
}
void loop() {
// Drive each PWM in a 'wave'
for (uint16_t i=0; i<4096; i += 8) {
for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
pwm.setPWM(pwmnum, 0, (i + (4096/16)*pwmnum) % 4096 );
}
}
}
The supporting code is in Adafruit_PWM.ino.
/***************************************************
This is a library for our Adafruit 16-channel PWM & Servo driver
Pick one up today in the adafruit shop!
------> http://www.adafruit.com/products/815
These displays use I2C to communicate, 2 pins are required to
interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
// #include <Adafruit_PWMServoDriver.h>
#include "Adafruit_PWMServoDriver.h"
#include <Wire.h>
#if defined(__AVR__)
#define WIRE Wire
#elif defined(CORE_TEENSY) // Teensy boards
#define WIRE Wire
#else // Arduino Due
#define WIRE Wire1
#endif
// Set to true to print some debug messages, or false to disable them.
#define ENABLE_DEBUG_OUTPUT true
Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(uint8_t addr) {
_i2caddr = addr;
}
void Adafruit_PWMServoDriver::begin(void) {
WIRE.begin();
reset();
}
void Adafruit_PWMServoDriver::reset(void) {
write8(PCA9685_MODE1, 0x0);
}
void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
//Serial.print("Attempting to set freq ");
//Serial.println(freq);
freq *= 0.9; // Correct for overshoot in the frequency setting (see issue #11).
float prescaleval = 25000000;
prescaleval /= 4096;
prescaleval /= freq;
prescaleval -= 1;
if (ENABLE_DEBUG_OUTPUT) {
Serial.print("Estimated pre-scale: "); Serial.println(prescaleval);
}
uint8_t prescale = floor(prescaleval + 0.5);
if (ENABLE_DEBUG_OUTPUT) {
Serial.print("Final pre-scale: "); Serial.println(prescale);
}
uint8_t oldmode = read8(PCA9685_MODE1);
uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
write8(PCA9685_MODE1, newmode); // go to sleep
write8(PCA9685_PRESCALE, prescale); // set the prescaler
write8(PCA9685_MODE1, oldmode);
delay(5);
write8(PCA9685_MODE1, oldmode | 0xa1); // This sets the MODE1 register to turn on auto increment.
// This is why the beginTransmission below was not working.
// Serial.print("Mode now 0x"); Serial.println(read8(PCA9685_MODE1), HEX);
}
void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
//Serial.print("Setting PWM "); Serial.print(num); Serial.print(": "); Serial.print(on); Serial.print("->"); Serial.println(off);
WIRE.beginTransmission(_i2caddr);
WIRE.write(LED0_ON_L+4*num);
WIRE.write(on);
WIRE.write(on>>8);
WIRE.write(off);
WIRE.write(off>>8);
WIRE.endTransmission();
}
// Sets pin without having to deal with on/off tick placement and properly handles
// a zero value as completely off. Optional invert parameter supports inverting
// the pulse for sinking to ground. Val should be a value from 0 to 4095 inclusive.
void Adafruit_PWMServoDriver::setPin(uint8_t num, uint16_t val, bool invert)
{
// Clamp value between 0 and 4095 inclusive.
val = min(val, 4095);
if (invert) {
if (val == 0) {
// Special value for signal fully on.
setPWM(num, 4096, 0);
}
else if (val == 4095) {
// Special value for signal fully off.
setPWM(num, 0, 4096);
}
else {
setPWM(num, 0, 4095-val);
}
}
else {
if (val == 4095) {
// Special value for signal fully on.
setPWM(num, 4096, 0);
}
else if (val == 0) {
// Special value for signal fully off.
setPWM(num, 0, 4096);
}
else {
setPWM(num, 0, val);
}
}
}
uint8_t Adafruit_PWMServoDriver::read8(uint8_t addr) {
WIRE.beginTransmission(_i2caddr);
WIRE.write(addr);
WIRE.endTransmission();
WIRE.requestFrom((uint8_t)_i2caddr, (uint8_t)1);
return WIRE.read();
}
void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
WIRE.beginTransmission(_i2caddr);
WIRE.write(addr);
WIRE.write(d);
WIRE.endTransmission();
}
The supporting definitions are in Adafruit_PWM.ino.
/***************************************************
This is a library for our Adafruit 16-channel PWM & Servo driver
Pick one up today in the adafruit shop!
------> http://www.adafruit.com/products/815
These displays use I2C to communicate, 2 pins are required to
interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#ifndef _ADAFRUIT_PWMServoDriver_H
#define _ADAFRUIT_PWMServoDriver_H
#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
#define PCA9685_SUBADR1 0x2
#define PCA9685_SUBADR2 0x3
#define PCA9685_SUBADR3 0x4
#define PCA9685_MODE1 0x0
#define PCA9685_PRESCALE 0xFE
#define LED0_ON_L 0x6
#define LED0_ON_H 0x7
#define LED0_OFF_L 0x8
#define LED0_OFF_H 0x9
#define ALLLED_ON_L 0xFA
#define ALLLED_ON_H 0xFB
#define ALLLED_OFF_L 0xFC
#define ALLLED_OFF_H 0xFD
class Adafruit_PWMServoDriver {
public:
Adafruit_PWMServoDriver(uint8_t addr = 0x40);
void begin(void);
void reset(void);
void setPWMFreq(float freq);
void setPWM(uint8_t num, uint16_t on, uint16_t off);
void setPin(uint8_t num, uint16_t val, bool invert=false);
private:
uint8_t _i2caddr;
uint8_t read8(uint8_t addr);
void write8(uint8_t addr, uint8_t d);
};
#endif
Source: Arduino Sketch Adafruit PWM
