70 lines
2.7 KiB
C++
70 lines
2.7 KiB
C++
/***************************************************
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This is an example for our Adafruit 16-channel PWM & Servo driver
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PWM test - this will drive 16 PWMs in a 'wave'
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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 drivers 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 <Wire.h>
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#include <Adafruit_PWMServoDriver.h>
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// called this way, it uses the default address 0x40
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Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
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// you can also call it with a different address you want
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//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);
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// you can also call it with a different address and I2C interface
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//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x40, Wire);
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void setup() {
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Serial.begin(9600);
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Serial.println("16 channel PWM test!");
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pwm.begin();
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/*
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* In theory the internal oscillator (clock) is 25MHz but it really isn't
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* that precise. You can 'calibrate' this by tweaking this number until
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* you get the PWM update frequency you're expecting!
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* The int.osc. for the PCA9685 chip is a range between about 23-27MHz and
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* is used for calculating things like writeMicroseconds()
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* Analog servos run at ~50 Hz updates, It is importaint to use an
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* oscilloscope in setting the int.osc frequency for the I2C PCA9685 chip.
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* 1) Attach the oscilloscope to one of the PWM signal pins and ground on
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* the I2C PCA9685 chip you are setting the value for.
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* 2) Adjust setOscillatorFrequency() until the PWM update frequency is the
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* expected value (50Hz for most ESCs)
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* Setting the value here is specific to each individual I2C PCA9685 chip and
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* affects the calculations for the PWM update frequency.
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* Failure to correctly set the int.osc value will cause unexpected PWM results
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*/
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pwm.setOscillatorFrequency(27000000);
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pwm.setPWMFreq(1600); // This is the maximum PWM frequency
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// if you want to really speed stuff up, you can go into 'fast 400khz I2C' mode
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// some i2c devices dont like this so much so if you're sharing the bus, watch
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// out for this!
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Wire.setClock(400000);
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}
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void loop() {
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// Drive each PWM in a 'wave'
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for (uint16_t i=0; i<4096; i += 8) {
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for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
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pwm.setPWM(pwmnum, 0, (i + (4096/16)*pwmnum) % 4096 );
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}
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#ifdef ESP8266
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yield(); // take a breather, required for ESP8266
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#endif
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}
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}
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