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/*!
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* @file Adafruit_PWMServoDriver.cpp
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*
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* @mainpage Adafruit 16-channel PWM & Servo driver
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*
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* @section intro_sec Introduction
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*
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* This is a library for the 16-channel PWM & Servo driver.
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*
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* Designed specifically to work with the Adafruit PWM & Servo driver.
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*
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* Pick one up today in the adafruit shop!
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* ------> https://www.adafruit.com/product/815
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*
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* These displays use I2C to communicate, 2 pins are required to interface.
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit andopen-source hardware by purchasing products
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* from Adafruit!
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*
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* @section author Author
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*
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* Limor Fried/Ladyada (Adafruit Industries).
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*
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* @section license License
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*
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* BSD license, all text above must be included in any redistribution
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*/
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#include "Adafruit_PWMServoDriver.h"
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#include <Wire.h>
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//#define ENABLE_DEBUG_OUTPUT
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/*!
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* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
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* TwoWire interface
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*/
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Adafruit_PWMServoDriver::Adafruit_PWMServoDriver()
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: _i2caddr(PCA9685_I2C_ADDRESS), _i2c(&Wire) {}
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/*!
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* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
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* TwoWire interface
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* @param addr The 7-bit I2C address to locate this chip, default is 0x40
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*/
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Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(const uint8_t addr)
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: _i2caddr(addr), _i2c(&Wire) {}
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/*!
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* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
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* TwoWire interface
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* @param addr The 7-bit I2C address to locate this chip, default is 0x40
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* @param i2c A reference to a 'TwoWire' object that we'll use to communicate
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* with
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*/
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Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(const uint8_t addr,
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TwoWire &i2c)
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: _i2caddr(addr), _i2c(&i2c) {}
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/*!
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* @brief Setups the I2C interface and hardware
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* @param prescale
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* Sets External Clock (Optional)
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*/
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void Adafruit_PWMServoDriver::begin(uint8_t prescale) {
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_i2c->begin();
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reset();
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if (prescale) {
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setExtClk(prescale);
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} else {
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// set a default frequency
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setPWMFreq(1000);
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}
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// set the default internal frequency
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setOscillatorFrequency(FREQUENCY_OSCILLATOR);
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}
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/*!
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* @brief Sends a reset command to the PCA9685 chip over I2C
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*/
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void Adafruit_PWMServoDriver::reset() {
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write8(PCA9685_MODE1, MODE1_RESTART);
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delay(10);
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}
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/*!
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* @brief Puts board into sleep mode
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*/
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void Adafruit_PWMServoDriver::sleep() {
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uint8_t awake = read8(PCA9685_MODE1);
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uint8_t sleep = awake | MODE1_SLEEP; // set sleep bit high
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write8(PCA9685_MODE1, sleep);
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delay(5); // wait until cycle ends for sleep to be active
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}
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/*!
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* @brief Wakes board from sleep
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*/
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void Adafruit_PWMServoDriver::wakeup() {
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uint8_t sleep = read8(PCA9685_MODE1);
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uint8_t wakeup = sleep & ~MODE1_SLEEP; // set sleep bit low
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write8(PCA9685_MODE1, wakeup);
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}
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/*!
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* @brief Sets EXTCLK pin to use the external clock
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* @param prescale
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* Configures the prescale value to be used by the external clock
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*/
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void Adafruit_PWMServoDriver::setExtClk(uint8_t prescale) {
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uint8_t oldmode = read8(PCA9685_MODE1);
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uint8_t newmode = (oldmode & ~MODE1_RESTART) | MODE1_SLEEP; // sleep
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write8(PCA9685_MODE1, newmode); // go to sleep, turn off internal oscillator
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// This sets both the SLEEP and EXTCLK bits of the MODE1 register to switch to
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// use the external clock.
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write8(PCA9685_MODE1, (newmode |= MODE1_EXTCLK));
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write8(PCA9685_PRESCALE, prescale); // set the prescaler
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delay(5);
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// clear the SLEEP bit to start
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write8(PCA9685_MODE1, (newmode & ~MODE1_SLEEP) | MODE1_RESTART | MODE1_AI);
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Mode now 0x");
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Serial.println(read8(PCA9685_MODE1), HEX);
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#endif
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}
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/*!
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* @brief Sets the PWM frequency for the entire chip, up to ~1.6 KHz
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* @param freq Floating point frequency that we will attempt to match
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*/
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void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Attempting to set freq ");
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Serial.println(freq);
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#endif
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// Range output modulation frequency is dependant on oscillator
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if (freq < 1)
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freq = 1;
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if (freq > 3500)
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freq = 3500; // Datasheet limit is 3052=50MHz/(4*4096)
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float prescaleval = ((_oscillator_freq / (freq * 4096.0)) + 0.5) - 1;
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if (prescaleval < PCA9685_PRESCALE_MIN)
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prescaleval = PCA9685_PRESCALE_MIN;
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if (prescaleval > PCA9685_PRESCALE_MAX)
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prescaleval = PCA9685_PRESCALE_MAX;
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uint8_t prescale = (uint8_t)prescaleval;
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Final pre-scale: ");
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Serial.println(prescale);
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#endif
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uint8_t oldmode = read8(PCA9685_MODE1);
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uint8_t newmode = (oldmode & ~MODE1_RESTART) | MODE1_SLEEP; // sleep
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write8(PCA9685_MODE1, newmode); // go to sleep
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write8(PCA9685_PRESCALE, prescale); // set the prescaler
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write8(PCA9685_MODE1, oldmode);
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delay(5);
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// This sets the MODE1 register to turn on auto increment.
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write8(PCA9685_MODE1, oldmode | MODE1_RESTART | MODE1_AI);
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Mode now 0x");
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Serial.println(read8(PCA9685_MODE1), HEX);
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#endif
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}
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/*!
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* @brief Sets the output mode of the PCA9685 to either
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* open drain or push pull / totempole.
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* Warning: LEDs with integrated zener diodes should
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* only be driven in open drain mode.
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* @param totempole Totempole if true, open drain if false.
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*/
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void Adafruit_PWMServoDriver::setOutputMode(bool totempole) {
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uint8_t oldmode = read8(PCA9685_MODE2);
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uint8_t newmode;
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if (totempole) {
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newmode = oldmode | MODE2_OUTDRV;
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} else {
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newmode = oldmode & ~MODE2_OUTDRV;
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}
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write8(PCA9685_MODE2, newmode);
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Setting output mode: ");
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Serial.print(totempole ? "totempole" : "open drain");
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Serial.print(" by setting MODE2 to ");
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Serial.println(newmode);
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#endif
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}
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/*!
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* @brief Reads set Prescale from PCA9685
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* @return prescale value
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*/
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uint8_t Adafruit_PWMServoDriver::readPrescale(void) {
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return read8(PCA9685_PRESCALE);
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}
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/*!
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* @brief Gets the PWM output of one of the PCA9685 pins
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* @param num One of the PWM output pins, from 0 to 15
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* @return requested PWM output value
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*/
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uint8_t Adafruit_PWMServoDriver::getPWM(uint8_t num) {
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_i2c->requestFrom((int)_i2caddr, PCA9685_LED0_ON_L + 4 * num, (int)4);
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return _i2c->read();
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}
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/*!
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* @brief Sets the PWM output of one of the PCA9685 pins
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* @param num One of the PWM output pins, from 0 to 15
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* @param on At what point in the 4096-part cycle to turn the PWM output ON
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* @param off At what point in the 4096-part cycle to turn the PWM output OFF
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*/
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void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Setting PWM ");
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Serial.print(num);
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Serial.print(": ");
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Serial.print(on);
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Serial.print("->");
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Serial.println(off);
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#endif
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_i2c->beginTransmission(_i2caddr);
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_i2c->write(PCA9685_LED0_ON_L + 4 * num);
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_i2c->write(on);
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_i2c->write(on >> 8);
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_i2c->write(off);
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_i2c->write(off >> 8);
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_i2c->endTransmission();
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}
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/*!
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* @brief Helper to set pin PWM output. Sets pin without having to deal with
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* on/off tick placement and properly handles a zero value as completely off and
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* 4095 as completely on. Optional invert parameter supports inverting the
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* pulse for sinking to ground.
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* @param num One of the PWM output pins, from 0 to 15
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* @param val The number of ticks out of 4096 to be active, should be a value
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* from 0 to 4095 inclusive.
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* @param invert If true, inverts the output, defaults to 'false'
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*/
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void Adafruit_PWMServoDriver::setPin(uint8_t num, uint16_t val, bool invert) {
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// Clamp value between 0 and 4095 inclusive.
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val = min(val, (uint16_t)4095);
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if (invert) {
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if (val == 0) {
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// Special value for signal fully on.
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setPWM(num, 4096, 0);
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} else if (val == 4095) {
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// Special value for signal fully off.
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setPWM(num, 0, 4096);
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} else {
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setPWM(num, 0, 4095 - val);
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}
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} else {
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if (val == 4095) {
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// Special value for signal fully on.
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setPWM(num, 4096, 0);
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} else if (val == 0) {
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// Special value for signal fully off.
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setPWM(num, 0, 4096);
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} else {
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setPWM(num, 0, val);
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}
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}
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}
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/*!
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* @brief Sets the PWM output of one of the PCA9685 pins based on the input
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* microseconds, output is not precise
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* @param num One of the PWM output pins, from 0 to 15
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* @param Microseconds The number of Microseconds to turn the PWM output ON
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*/
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void Adafruit_PWMServoDriver::writeMicroseconds(uint8_t num,
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uint16_t Microseconds) {
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Setting PWM Via Microseconds on output");
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Serial.print(num);
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Serial.print(": ");
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Serial.print(Microseconds);
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Serial.println("->");
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#endif
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double pulse = Microseconds;
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double pulselength;
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pulselength = 1000000; // 1,000,000 us per second
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// Read prescale
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uint16_t prescale = readPrescale();
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print(prescale);
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Serial.println(" PCA9685 chip prescale");
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#endif
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// Calculate the pulse for PWM based on Equation 1 from the datasheet section
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// 7.3.5
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prescale += 1;
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pulselength *= prescale;
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pulselength /= _oscillator_freq;
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print(pulselength);
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Serial.println(" us per bit");
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#endif
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pulse /= pulselength;
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print(pulse);
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Serial.println(" pulse for PWM");
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#endif
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setPWM(num, 0, pulse);
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}
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/*!
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* @brief Getter for the internally tracked oscillator used for freq
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* calculations
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* @returns The frequency the PCA9685 thinks it is running at (it cannot
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* introspect)
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*/
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uint32_t Adafruit_PWMServoDriver::getOscillatorFrequency(void) {
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return _oscillator_freq;
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}
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/*!
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* @brief Setter for the internally tracked oscillator used for freq
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* calculations
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* @param freq The frequency the PCA9685 should use for frequency calculations
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*/
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void Adafruit_PWMServoDriver::setOscillatorFrequency(uint32_t freq) {
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_oscillator_freq = freq;
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}
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/******************* Low level I2C interface */
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uint8_t Adafruit_PWMServoDriver::read8(uint8_t addr) {
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_i2c->beginTransmission(_i2caddr);
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_i2c->write(addr);
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_i2c->endTransmission();
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_i2c->requestFrom((uint8_t)_i2caddr, (uint8_t)1);
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return _i2c->read();
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}
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void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
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_i2c->beginTransmission(_i2caddr);
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_i2c->write(addr);
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_i2c->write(d);
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_i2c->endTransmission();
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}
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