Program/hal/hal-pca9685/doc/Adafruit-PWM-Servo-Driver-L.../Adafruit_PWMServoDriver.cpp

375 lines
11 KiB
C++

/*!
* @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"
//#define ENABLE_DEBUG_OUTPUT
/*!
* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
* TwoWire interface
*/
Adafruit_PWMServoDriver::Adafruit_PWMServoDriver()
: _i2caddr(PCA9685_I2C_ADDRESS), _i2c(&Wire) {}
/*!
* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
* TwoWire interface
* @param addr The 7-bit I2C address to locate this chip, default is 0x40
*/
Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(const uint8_t addr)
: _i2caddr(addr), _i2c(&Wire) {}
/*!
* @brief Instantiates a new PCA9685 PWM driver chip with the I2C address on a
* TwoWire interface
* @param addr The 7-bit I2C address to locate this chip, default is 0x40
* @param i2c A reference to a 'TwoWire' object that we'll use to communicate
* with
*/
Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(const uint8_t addr,
TwoWire &i2c)
: _i2caddr(addr), _i2c(&i2c) {}
/*!
* @brief Setups the I2C interface and hardware
* @param prescale
* Sets External Clock (Optional)
* @return true if successful, otherwise false
*/
bool Adafruit_PWMServoDriver::begin(uint8_t prescale) {
if (i2c_dev)
delete i2c_dev;
i2c_dev = new Adafruit_I2CDevice(_i2caddr, _i2c);
if (!i2c_dev->begin())
return false;
reset();
// set the default internal frequency
setOscillatorFrequency(FREQUENCY_OSCILLATOR);
if (prescale) {
setExtClk(prescale);
} else {
// set a default frequency
setPWMFreq(1000);
}
return true;
}
/*!
* @brief Sends a reset command to the PCA9685 chip over I2C
*/
void Adafruit_PWMServoDriver::reset() {
write8(PCA9685_MODE1, MODE1_RESTART);
delay(10);
}
/*!
* @brief Puts board into sleep mode
*/
void Adafruit_PWMServoDriver::sleep() {
uint8_t awake = read8(PCA9685_MODE1);
uint8_t sleep = awake | MODE1_SLEEP; // 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 & ~MODE1_SLEEP; // 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 & ~MODE1_RESTART) | MODE1_SLEEP; // 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 |= MODE1_EXTCLK));
write8(PCA9685_PRESCALE, prescale); // set the prescaler
delay(5);
// clear the SLEEP bit to start
write8(PCA9685_MODE1, (newmode & ~MODE1_SLEEP) | MODE1_RESTART | MODE1_AI);
#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
// Range output modulation frequency is dependant on oscillator
if (freq < 1)
freq = 1;
if (freq > 3500)
freq = 3500; // Datasheet limit is 3052=50MHz/(4*4096)
float prescaleval = ((_oscillator_freq / (freq * 4096.0)) + 0.5) - 1;
if (prescaleval < PCA9685_PRESCALE_MIN)
prescaleval = PCA9685_PRESCALE_MIN;
if (prescaleval > PCA9685_PRESCALE_MAX)
prescaleval = PCA9685_PRESCALE_MAX;
uint8_t prescale = (uint8_t)prescaleval;
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Final pre-scale: ");
Serial.println(prescale);
#endif
uint8_t oldmode = read8(PCA9685_MODE1);
uint8_t newmode = (oldmode & ~MODE1_RESTART) | MODE1_SLEEP; // sleep
write8(PCA9685_MODE1, newmode); // go to sleep
write8(PCA9685_PRESCALE, prescale); // set the prescaler
write8(PCA9685_MODE1, oldmode);
delay(5);
// This sets the MODE1 register to turn on auto increment.
write8(PCA9685_MODE1, oldmode | MODE1_RESTART | MODE1_AI);
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Mode now 0x");
Serial.println(read8(PCA9685_MODE1), HEX);
#endif
}
/*!
* @brief Sets the output mode of the PCA9685 to either
* open drain or push pull / totempole.
* Warning: LEDs with integrated zener diodes should
* only be driven in open drain mode.
* @param totempole Totempole if true, open drain if false.
*/
void Adafruit_PWMServoDriver::setOutputMode(bool totempole) {
uint8_t oldmode = read8(PCA9685_MODE2);
uint8_t newmode;
if (totempole) {
newmode = oldmode | MODE2_OUTDRV;
} else {
newmode = oldmode & ~MODE2_OUTDRV;
}
write8(PCA9685_MODE2, newmode);
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Setting output mode: ");
Serial.print(totempole ? "totempole" : "open drain");
Serial.print(" by setting MODE2 to ");
Serial.println(newmode);
#endif
}
/*!
* @brief Reads set Prescale from PCA9685
* @return prescale value
*/
uint8_t Adafruit_PWMServoDriver::readPrescale(void) {
return read8(PCA9685_PRESCALE);
}
/*!
* @brief Gets the PWM output of one of the PCA9685 pins
* @param num One of the PWM output pins, from 0 to 15
* @param off If true, returns PWM OFF value, otherwise PWM ON
* @return requested PWM output value
*/
uint16_t Adafruit_PWMServoDriver::getPWM(uint8_t num, bool off) {
uint8_t buffer[2] = {uint8_t(PCA9685_LED0_ON_L + 4 * num), 0};
if (off)
buffer[0] += 2;
i2c_dev->write_then_read(buffer, 1, buffer, 2);
return uint16_t(buffer[0]) | (uint16_t(buffer[1]) << 8);
}
/*!
* @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
* @return 0 if successful, otherwise 1
*/
uint8_t 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
uint8_t buffer[5];
buffer[0] = PCA9685_LED0_ON_L + 4 * num;
buffer[1] = on;
buffer[2] = on >> 8;
buffer[3] = off;
buffer[4] = off >> 8;
if (i2c_dev->write(buffer, 5)) {
return 0;
} else {
return 1;
}
}
/*!
* @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);
}
}
}
/*!
* @brief Sets the PWM output of one of the PCA9685 pins based on the input
* microseconds, output is not precise
* @param num One of the PWM output pins, from 0 to 15
* @param Microseconds The number of Microseconds to turn the PWM output ON
*/
void Adafruit_PWMServoDriver::writeMicroseconds(uint8_t num,
uint16_t Microseconds) {
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print("Setting PWM Via Microseconds on output");
Serial.print(num);
Serial.print(": ");
Serial.print(Microseconds);
Serial.println("->");
#endif
double pulse = Microseconds;
double pulselength;
pulselength = 1000000; // 1,000,000 us per second
// Read prescale
uint16_t prescale = readPrescale();
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print(prescale);
Serial.println(" PCA9685 chip prescale");
#endif
// Calculate the pulse for PWM based on Equation 1 from the datasheet section
// 7.3.5
prescale += 1;
pulselength *= prescale;
pulselength /= _oscillator_freq;
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print(pulselength);
Serial.println(" us per bit");
#endif
pulse /= pulselength;
#ifdef ENABLE_DEBUG_OUTPUT
Serial.print(pulse);
Serial.println(" pulse for PWM");
#endif
setPWM(num, 0, pulse);
}
/*!
* @brief Getter for the internally tracked oscillator used for freq
* calculations
* @returns The frequency the PCA9685 thinks it is running at (it cannot
* introspect)
*/
uint32_t Adafruit_PWMServoDriver::getOscillatorFrequency(void) {
return _oscillator_freq;
}
/*!
* @brief Setter for the internally tracked oscillator used for freq
* calculations
* @param freq The frequency the PCA9685 should use for frequency calculations
*/
void Adafruit_PWMServoDriver::setOscillatorFrequency(uint32_t freq) {
_oscillator_freq = freq;
}
/******************* Low level I2C interface */
uint8_t Adafruit_PWMServoDriver::read8(uint8_t addr) {
uint8_t buffer[1] = {addr};
i2c_dev->write_then_read(buffer, 1, buffer, 1);
return buffer[0];
}
void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
uint8_t buffer[2] = {addr, d};
i2c_dev->write(buffer, 2);
}