PCA9685 16-Channel 12-Bit PWM Driver

PCA9685 (pdf reference) is a popular controller among Arduino and Raspberry PI developers. The 16-Channel 12-bit PWM/Servo Driver will drive up to 16 servos over I2C with only 2 pins. The on-board PWM controller will drive all 16 channels. What's more, you can chain up to 62 of them to control up to 992 servos - all with the same 2 pins!

Here is a library written in Go programming language for Raspberry PI and counterparts.

Golang usage

package main

import (
	"log"
	"time"

	"github.com/googolgl/go-i2c"
	"github.com/googolgl/go-pca9685"
)

func main() {
    // Create new connection to i2c-bus on 1 line with address 0x40.
    // Use i2cdetect utility to find device address over the i2c-bus
    i2c, err := i2c.New(pca9685.Address, "/dev/12c-0")
    if err != nil {
        log.Fatal(err)
    }

    pca0, err := pca9685.New(i2c, nil)
    if err != nil {
        log.Fatal(err)
    }

    // Sets a single PWM channel 0
    pca0.SetChannel(0, 0, 130)

    // Servo on channel 0
    servo0 := pca0.ServoNew(0, nil)

    // Angle in degrees. Must be in the range `0` to `Range`
    for i := 0; i < 130; i++ {
        servo0.Angle(i)
        time.Sleep(10 * time.Millisecond)
    }

    // Fraction as pulse width expressed between 0.0 `MinPulse` and 1.0 `MaxPulse`
    servo0.Fraction(0.5)
}

Getting help

GoDoc documentation

Installation

$ go get -u github.com/googolgl/go-pca9685

Troubleshooting

How to obtain fresh Golang installation to RPi device (either any RPi clone): If your RaspberryPI golang installation taken by default from repository is outdated, you may consider to install actual golang manually from official Golang site. Download tar.gz file containing arm64 in the name. Follow installation instructions.
How to enable I2C bus on RPi device: If you employ RaspberryPI, use raspi-config utility to activate i2c-bus on the OS level. Go to "Interfacing Options" menu, to active I2C bus. Probably you will need to reboot to load i2c kernel module. Finally you should have device like /dev/i2c-1 present in the system.

How to find I2C bus allocation and device address: Use i2cdetect utility in format "i2cdetect -y X", where X may vary from 0 to 5 or more, to discover address occupied by peripheral device. To install utility you should run apt install i2c-tools on debian-kind system. i2cdetect -y 1 sample output:

      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
 70: -- -- -- -- -- -- 76 --

Contact

Please use Github issue tracker for filing bugs or feature requests.

License

Go-pca9685 is licensed under MIT License.