Andrew Lindsay / Adafruit_PWMServoDriver

This is a library for our Adafruit 16-channel PWM or any other board that uses the PCA9685 I2C PWM driver chip.

Dependents:   K9_Head_Controller

Adafruit_PWMServoDriver.cpp@6:a76057c4c7ac, 2021-06-26 (annotated)

Committer:
SomeRandomBloke
Date:
Sat Jun 26 12:05:53 2021 +0000
Revision:
6:a76057c4c7ac
Parent:
5:9ff15661ddd6 
moved to Mbed OS 6

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bxd 0:ed0c8a6481fd 1 /***************************************************
bxd 0:ed0c8a6481fd 2 This is a library for our Adafruit 16-channel PWM & Servo driver
bxd 0:ed0c8a6481fd 3
bxd 0:ed0c8a6481fd 4 Pick one up today in the adafruit shop!
bxd 0:ed0c8a6481fd 5 ------> http://www.adafruit.com/products/815
bxd 0:ed0c8a6481fd 6
bxd 0:ed0c8a6481fd 7 These displays use I2C to communicate, 2 pins are required to
bxd 0:ed0c8a6481fd 8 interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
bxd 0:ed0c8a6481fd 9
bxd 0:ed0c8a6481fd 10 Adafruit invests time and resources providing this open source code,
bxd 0:ed0c8a6481fd 11 please support Adafruit and open-source hardware by purchasing
bxd 0:ed0c8a6481fd 12 products from Adafruit!
bxd 0:ed0c8a6481fd 13
bxd 0:ed0c8a6481fd 14 Written by Limor Fried/Ladyada for Adafruit Industries.
bxd 0:ed0c8a6481fd 15 BSD license, all text above must be included in any redistribution
bxd 0:ed0c8a6481fd 16
bxd 0:ed0c8a6481fd 17 Ported to mbed by Brian Dickman, mbed.org user bxd.
bxd 0:ed0c8a6481fd 18 ****************************************************/
bxd 0:ed0c8a6481fd 19
bxd 0:ed0c8a6481fd 20 #include <Adafruit_PWMServoDriver.h>
bxd 0:ed0c8a6481fd 21
bxd 0:ed0c8a6481fd 22 Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(I2C *i2c, uint8_t addr) {
bxd 0:ed0c8a6481fd 23 _i2c = i2c;
bxd 0:ed0c8a6481fd 24
bxd 0:ed0c8a6481fd 25 // Arduino WIRE library takes address as 7-bit (unshifted), mbed takes 8 bit.
bxd 4:41a00db32ae7 26 // in other words, use the Adafruit library default value 0x40 to talk with the breakout
bxd 4:41a00db32ae7 27 // if you use the default resistor config.
bxd 0:ed0c8a6481fd 28 _i2caddr = addr << 1;
bxd 0:ed0c8a6481fd 29 }
bxd 0:ed0c8a6481fd 30
bxd 0:ed0c8a6481fd 31 void Adafruit_PWMServoDriver::begin(void) {
bxd 0:ed0c8a6481fd 32 reset();
bxd 0:ed0c8a6481fd 33 }
bxd 0:ed0c8a6481fd 34
bxd 0:ed0c8a6481fd 35
bxd 0:ed0c8a6481fd 36 void Adafruit_PWMServoDriver::reset(void) {
bxd 3:5e1fd11c4f94 37
bxd 3:5e1fd11c4f94 38 // leave the ALL CALL address enabled (we might use that!)
bxd 3:5e1fd11c4f94 39 // if you don't want ALL CALL, write 00 to offset 00
bxd 3:5e1fd11c4f94 40 write8(PCA9685_MODE1, 0x1);
bxd 0:ed0c8a6481fd 41 }
bxd 0:ed0c8a6481fd 42
bxd 0:ed0c8a6481fd 43 void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
bxd 0:ed0c8a6481fd 44 //Serial.print("Attempting to set freq ");
bxd 0:ed0c8a6481fd 45 //Serial.println(freq);
bxd 0:ed0c8a6481fd 46
bxd 0:ed0c8a6481fd 47 float prescaleval = 25000000;
bxd 0:ed0c8a6481fd 48 prescaleval /= 4096;
bxd 0:ed0c8a6481fd 49 prescaleval /= freq;
bxd 0:ed0c8a6481fd 50 prescaleval -= 1;
SomeRandomBloke 6:a76057c4c7ac 51 //debug("Estimated pre-scale: %f\r\n", prescaleval);
bxd 0:ed0c8a6481fd 52 uint8_t prescale = floor(prescaleval + 0.5);
SomeRandomBloke 6:a76057c4c7ac 53 //debug("Final pre-scale: %f", prescale);
bxd 0:ed0c8a6481fd 54
bxd 0:ed0c8a6481fd 55 uint8_t oldmode = read8(PCA9685_MODE1);
bxd 0:ed0c8a6481fd 56 uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
bxd 0:ed0c8a6481fd 57 write8(PCA9685_MODE1, newmode); // go to sleep
bxd 0:ed0c8a6481fd 58 write8(PCA9685_PRESCALE, prescale); // set the prescaler
bxd 0:ed0c8a6481fd 59 write8(PCA9685_MODE1, oldmode);
SomeRandomBloke 5:9ff15661ddd6 60 wait_us(5000);
bxd 0:ed0c8a6481fd 61 write8(PCA9685_MODE1, oldmode | 0xa1); // This sets the MODE1 register to turn on auto increment.
bxd 0:ed0c8a6481fd 62 // This is why the beginTransmission below was not working.
bxd 0:ed0c8a6481fd 63 // Serial.print("Mode now 0x"); Serial.println(read8(PCA9685_MODE1), HEX);
bxd 0:ed0c8a6481fd 64 }
bxd 0:ed0c8a6481fd 65
bxd 0:ed0c8a6481fd 66 void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
bxd 0:ed0c8a6481fd 67 //Serial.print("Setting PWM "); Serial.print(num); Serial.print(": "); Serial.print(on); Serial.print("->"); Serial.println(off);
bxd 0:ed0c8a6481fd 68
SomeRandomBloke 5:9ff15661ddd6 69 uint8_t data[] = { (uint8_t)(LED0_ON_L+4*num), (uint8_t)on, (uint8_t)(on >> 8), (uint8_t)off, (uint8_t)(off >> 8) };
bxd 0:ed0c8a6481fd 70 _i2c->write(_i2caddr, (const char *)data, 5);
bxd 0:ed0c8a6481fd 71 }
bxd 0:ed0c8a6481fd 72
bxd 0:ed0c8a6481fd 73 uint8_t Adafruit_PWMServoDriver::read8(uint8_t addr) {
bxd 0:ed0c8a6481fd 74 char data;
bxd 3:5e1fd11c4f94 75 if(_i2c->write(_i2caddr, (char *)&addr, 1, true))
SomeRandomBloke 6:a76057c4c7ac 76 debug("I2C ERR: no ack on write before read.\n");
bxd 3:5e1fd11c4f94 77 if(_i2c->read(_i2caddr, &data, 1))
SomeRandomBloke 6:a76057c4c7ac 78 debug("I2C ERR: no ack on read\n");
bxd 0:ed0c8a6481fd 79 return (uint8_t)data;
bxd 0:ed0c8a6481fd 80 }
bxd 0:ed0c8a6481fd 81
bxd 0:ed0c8a6481fd 82 void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
bxd 0:ed0c8a6481fd 83 char data[] = { addr, d };
bxd 1:ac6c5e17c3d3 84 if(_i2c->write(_i2caddr, data, 2))
bxd 1:ac6c5e17c3d3 85 {
SomeRandomBloke 6:a76057c4c7ac 86 debug("I2C ERR: No ACK on i2c write!");
bxd 1:ac6c5e17c3d3 87 }
bxd 0:ed0c8a6481fd 88 }