What is it and why use this board?

This board is Arduino compatible ATmega 328P micro controller development board with PCA9685 16 channel pulse width modulation controller. It can be used for all sorts of LED lighting and servo motor controller applications. Development board takes less space than full sized Arduino kit with PWM shield. It is built on four layers PCB and measures just 7.5 x 4.5 cm - about the size of a credit card.

PCA9685 is controlled using I2C connection that is hardwired to micro controller. Additional I2C devices can be connected as well. On board there are 16 PWM connectors using 3 pin servo motor style connectors. PCA9685 outputs can be configured as push/pull or open drain outputs for more specific applications. All Arduino pins are available and are labeled according to pin names.

Note that micro controller runs at 3.3V and Arduino input pins can not use 5V input levels.

Technical details

Board can be powered from 5 – 15 V DC input (barrel jack plug or screw in terminal). Same input voltage will be used for powering servos or leds. Onboard 3.3V regulator provides voltage for micro controller and PWM ic.

Micro controller runs at 3.3V volts and uses 8 Mhz oscillator as clock source. There is 6-pin ICSP connector and FTDI style USB serial breakout board connector. There is no USB to serial converter on board. Input level shifters are used for serial and ICSP connections so it is possible to use 5V USB to serial adapter or AVR programmer.

Additional USB to serial breakout board is needed for reprogramming from Arduino IDE or to use serial console. USB to serial adapter using SparkFun FTDI Basic 6 pin connection pin-out should be used. Connector for serial breakout board uses female header.

Additional information

ATmega micro controller is flashed with Arduino bootloader and blinking LED sketch. Board will have pin headers soldered as seen on pictures. If you prefer something else for pin connections let me know. It might be possible to arrange according to what is available. There is space for additional power supply capacitor that is not soldered in. It may help to reduce servo motors power voltage ripple. Schematic, more detailed manual and example code files are available at GitHub page (see Documentation link below). If you have any specific question, don’t hesitate to ask.