Adafruit PWM driver I2C and SAMD21 Xplained pro

if you are looking to expand your I/O ports and control multi LED or Servo motor , so you need to use something similar to Adafruit PWM driver , based on PCA9685 I2C chip

in this quick tutorial I will show you how to control this breakout using SAMD21 Xplained pro

you need first to take a look at adafruit article about this part from here

connection :

PA08 >>> SDA

PA09 >>> SCL

VCC >>> VCC

GND >>> GND

And you need to connect V+ to positive power supply "you need an external power supply"

code instruction :

void PCA9685_begin();

to start I2C communication

void PCA9685_reset();

reset the chip registers.

void PCA9685_setPWMFreq(float freq);

set the PWM frequency where

freq :frequency in Hz ( 40 - 1600)

void PCA9685_setPWM(uint8_t num, uint16_t on, uint16_t off);

set the channel PWM value where :

num: channel number (0 - 15 )

on : high pulse value ( 0-4095 )

off : low pulse value ( 0-4095 )

void PCA9685_write(uint8_t addr, uint8_t data);

write I2C message to PCA9685 ,Where:

addr: adress of the register

data : from 0 - 255

uint8_t PCA9685_read(uint8_t addr);

read a byte from PCA9685

I used atmel start to setup the I2C and serial port configuration for this project , I used Master synchronous driver for this project.

simple code :

set the channel 1 with duty cycle of 50% and frequency of 1000 Hz

download the code from here

open the serial monitor to see the result and set the buadrate on 115200

second code :

control 4 Servo motors , connected from Channel 0 - 3 and rotate each motor from 0 > 180 degree and then go back to 0

open the serial monitor to see the result and set the buadrate on 115200

download the code from here

and this video will show you the results

High speed + I2C Mode

this part can run using SCL up to 1MHz , so I tested it out and it works fine to me , if you are looking to use higher clk speed like that you can use this code, it must give you the same results.