195 lines
6.5 KiB
C++
195 lines
6.5 KiB
C++
/***************************************************
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This is a library for our Adafruit 16-channel PWM & Servo driver
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Pick one up today in the adafruit shop!
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------> http://www.adafruit.com/products/815
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These displays use I2C to communicate, 2 pins are required to
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interface.
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Adafruit invests time and resources providing this open source code,
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please support Adafruit and open-source hardware by purchasing
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products from Adafruit!
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Written by Limor Fried/Ladyada for Adafruit Industries.
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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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// Set to true to print some debug messages, or false to disable them.
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//#define ENABLE_DEBUG_OUTPUT
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/**************************************************************************/
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/*!
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@brief Instantiates a new PCA9685 PWM driver chip with the I2C address on the Wire interface. On Due we use Wire1 since its the interface on the 'default' I2C pins.
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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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/**************************************************************************/
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Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(uint8_t addr) {
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_i2caddr = addr;
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#if defined(ARDUINO_SAM_DUE)
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_i2c = &Wire1;
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#else
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_i2c = &Wire;
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#endif
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}
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/**************************************************************************/
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/*!
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@brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a TwoWire interface
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@param i2c A pointer to a 'Wire' compatible object that we'll use to communicate with
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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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/**************************************************************************/
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Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(TwoWire *i2c, uint8_t addr) {
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_i2c = i2c;
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_i2caddr = addr;
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}
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/**************************************************************************/
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/*!
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@brief Setups the I2C interface and hardware
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*/
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/**************************************************************************/
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void Adafruit_PWMServoDriver::begin(void) {
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_i2c->begin();
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reset();
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// set a default frequency
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setPWMFreq(1000);
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}
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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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/**************************************************************************/
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void Adafruit_PWMServoDriver::reset(void) {
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write8(PCA9685_MODE1, 0x80);
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delay(10);
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}
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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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/**************************************************************************/
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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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freq *= 0.9; // Correct for overshoot in the frequency setting (see issue #11).
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float prescaleval = 25000000;
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prescaleval /= 4096;
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prescaleval /= freq;
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prescaleval -= 1;
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Estimated pre-scale: "); Serial.println(prescaleval);
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#endif
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uint8_t prescale = floor(prescaleval + 0.5);
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Final pre-scale: "); 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&0x7F) | 0x10; // 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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write8(PCA9685_MODE1, oldmode | 0xa0); // This sets the MODE1 register to turn on auto increment.
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#ifdef ENABLE_DEBUG_OUTPUT
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Serial.print("Mode now 0x"); Serial.println(read8(PCA9685_MODE1), HEX);
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#endif
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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
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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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/**************************************************************************/
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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 "); Serial.print(num); Serial.print(": "); Serial.print(on); Serial.print("->"); Serial.println(off);
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#endif
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_i2c->beginTransmission(_i2caddr);
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_i2c->write(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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/*!
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@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.
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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 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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/**************************************************************************/
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void Adafruit_PWMServoDriver::setPin(uint8_t num, uint16_t val, bool invert)
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{
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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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}
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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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}
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else {
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setPWM(num, 0, 4095-val);
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}
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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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}
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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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}
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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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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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