Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
9 contributors

Users who have contributed to this file

@ladyada @hoffmannjan @tdicola @PaintYourDragon @andydoro @larz99 @theJenix @adammhaile @per1234
executable file 247 lines (222 sloc) 6.94 KB
/*!
* @file Adafruit_PWMServoDriver.cpp
*
* @mainpage Adafruit 16-channel PWM & Servo driver
*
* @section intro_sec Introduction
*
* This is a library for the 16-channel PWM & Servo driver.
*
* Designed specifically to work with the Adafruit PWM & Servo driver.
*
* Pick one up today in the adafruit shop!
* ------> https://www.adafruit.com/product/815
*
* These displays use I2C to communicate, 2 pins are required to interface.
*
* Adafruit invests time and resources providing this open source code,
* please support Adafruit andopen-source hardware by purchasing products
* from Adafruit!
*
* @section author Author
*
* Limor Fried/Ladyada (Adafruit Industries).
*
* @section license License
*
* BSD license, all text above must be included in any redistribution
*/
#include "Adafruit_PWMServoDriver.h"
#include <Wire.h>
/*!
* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
* TwoWire interface
* @param i2c A pointer to a 'Wire' compatible object that we'll use to
* communicate with
* @param addr The 7-bit I2C address to locate this chip, default is 0x40
*/
Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(TwoWire *i2c, uint8_t addr) {
_i2c = i2c;
_i2caddr = addr;
}
/*!
* @brief Setups the I2C interface and hardware
* @param prescale
* Sets External Clock (Optional)
*
*/
void Adafruit_PWMServoDriver::begin(uint8_t prescale) {
_i2c->begin();
reset();
if (prescale) {
setExtClk(prescale);
} else {
// set a default frequency
setPWMFreq(1000);
}
}
/*!
* @brief Sends a reset command to the PCA9685 chip over I2C
*/
void Adafruit_PWMServoDriver::reset() {
write8(PCA9685_MODE1, 0x80);
delay(10);
}
/*!
* @brief Puts board into sleep mode
*/
void Adafruit_PWMServoDriver::sleep() {
uint8_t awake = read8(PCA9685_MODE1);
uint8_t sleep = awake | 0x10; // set sleep bit high
write8(PCA9685_MODE1, sleep);
delay(5); // wait until cycle ends for sleep to be active
}
/*!
* @brief Wakes board from sleep
*/
void Adafruit_PWMServoDriver::wakeup() {
uint8_t sleep = read8(PCA9685_MODE1);
uint8_t wakeup = sleep & ~0x10; // set sleep bit low
write8(PCA9685_MODE1, wakeup);
}
/**************************************************************************/
/*!
@brief Sets EXTCLK pin to use the external clock
@param prescale Configures the prescale value to be used by the external
clock
*/
/**************************************************************************/
void Adafruit_PWMServoDriver::setExtClk(uint8_t prescale) {
uint8_t oldmode = read8(PCA9685_MODE1);
uint8_t newmode = (oldmode & 0x7F) | 0x10; // sleep
write8(PCA9685_MODE1, newmode); // go to sleep, turn off internal oscillator
// This sets both the SLEEP and EXTCLK bits of the MODE1 register to switch to
// use the external clock.
write8(PCA9685_MODE1, (newmode |= 0x40));
write8(PCA9685_PRESCALE, prescale); // set the prescaler
delay(5);
write8(PCA9685_MODE1,
(newmode & ~(0x10)) | 0xa0); // clear the SLEEP bit to start
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Mode now 0x");
Serial.println(read8(PCA9685_MODE1), HEX);
#endif
}
/*!
* @brief Sets the PWM frequency for the entire chip, up to ~1.6 KHz
* @param freq Floating point frequency that we will attempt to match
*/
void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Attempting to set freq ");
Serial.println(freq);
#endif
freq *=
0.9; // Correct for overshoot in the frequency setting (see issue #11).
float prescaleval = 25000000;
prescaleval /= 4096;
prescaleval /= freq;
prescaleval -= 1;
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Estimated pre-scale: ");
Serial.println(prescaleval);
#endif
uint8_t prescale = floor(prescaleval + 0.5);
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Final pre-scale: ");
Serial.println(prescale);
#endif
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 |
0xa0); // This sets the MODE1 register to turn on auto increment.
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Mode now 0x");
Serial.println(read8(PCA9685_MODE1), HEX);
#endif
}
/*!
* @brief Gets the PWM output of one of the PCA9685 pins
* @param num One of the PWM output pins, from 0 to 15
* @return requested PWM output value
*/
uint8_t Adafruit_PWMServoDriver::getPWM(uint8_t num) {
_i2c->requestFrom((uint8_t)_i2caddr, LED0_ON_L + 4 * num, (uint8_t)4);
return _i2c->read();
}
/*!
* @brief Sets the PWM output of one of the PCA9685 pins
* @param num One of the PWM output pins, from 0 to 15
* @param on At what point in the 4096-part cycle to turn the PWM output ON
* @param off At what point in the 4096-part cycle to turn the PWM output OFF
*/
void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Setting PWM ");
Serial.print(num);
Serial.print(": ");
Serial.print(on);
Serial.print("->");
Serial.println(off);
#endif
_i2c->beginTransmission(_i2caddr);
_i2c->write(LED0_ON_L + 4 * num);
_i2c->write(on);
_i2c->write(on >> 8);
_i2c->write(off);
_i2c->write(off >> 8);
_i2c->endTransmission();
}
/*!
* @brief Helper to set pin PWM output. Sets pin without having to deal with
* on/off tick placement and properly handles a zero value as completely off and
* 4095 as completely on. Optional invert parameter supports inverting the
* pulse for sinking to ground.
* @param num One of the PWM output pins, from 0 to 15
* @param val The number of ticks out of 4096 to be active, should be a value
* from 0 to 4095 inclusive.
* @param invert If true, inverts the output, defaults to 'false'
*/
void Adafruit_PWMServoDriver::setPin(uint8_t num, uint16_t val, bool invert) {
// Clamp value between 0 and 4095 inclusive.
val = min(val, (uint16_t)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) {
_i2c->beginTransmission(_i2caddr);
_i2c->write(addr);
_i2c->endTransmission();
_i2c->requestFrom((uint8_t)_i2caddr, (uint8_t)1);
return _i2c->read();
}
void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
_i2c->beginTransmission(_i2caddr);
_i2c->write(addr);
_i2c->write(d);
_i2c->endTransmission();
}
You can’t perform that action at this time.