Serial and ISP Breadboard Adapter

Serial and ISP Breadboard Adapter

The Serial and ISP Breadboard Adapter is perfect for quick breadboarding with the ATMega328P chip. It gives you quick and easy access to the required programming headers leaving you free to prototype your design without worrying about cables and clutter!

Breadboard prototyping with ATMega328P in four easy steps:


Plug the ATMega328P chip into the breadboard


Plug the Serial and ISP Breadboard Adapter in on top of the processor


Plug your FTDI serial adapter (not included) into the serial port header, and attach the USB port to your computer. You should see the power LED light up.

The pictured FTDI adapter is theAkafugu FTDI Adapter, however any serial adapter with a 6-pin header can be used (Typically marked with DTR,TXD,RXI,VCC,GND,GND or DTR,TXD,RXI,VCC,CST,GND)

(If you have an ISP programmer, you can use the ISP header instead and download your binary directly using avrdude)

STEP 3A (16MHz version only)

The Serial ISP Adapter comes in two versions: An 8MHz version that uses the internal oscillator on the ATMega328P chip and a 16MHz version that uses an external crystal.

If you have the 16MHz version, you must plug in the crystal and the two 22pF capacitors.

First, locate the pins marked X1 and X2. Place the 16MHz crystal with one leg in X1 and one in X2 (orientation does not matter). Place the crystal on the column closest to the Serial ISP Adapter (usually marked 'c' on the breadboard). You should have two more columns free on the breadboard, usually marked 'a' and 'b'.

The pin left of X1 is marked GND. Place one 22pF capacitor between X1 and the GND pin in the column closest to the crystal (usually marked 'b'). The second 22pF capacitor goes between X2 and the GND pin in the outer column (usually marked 'a').


Open the Arduino IDE and download your sketch! The included ATMega328P comes pre-programmed with an Arduino-compatible bootloader, so it is ready for use directly.

Try the blink sketch to see the onboard user LED blinking.



  • ATMega328P included. Comes with bootloader preloaded for direct use with the Arduino IDE
  • Power LED
  • User LED on port D13, just like on a normal Arduino
  • Serial port for connecting to an FTDI adapter
  • ISP port for connection to an ISP programmer

The concept of the serial and ISP adapter is simple: Develop whatever circuit you desire directly on a breadboard without the extra clutter required to hook up a serial header or an ISP header.

PS: To use with the Arduino IDE, you will need an USB to Serial adapter. If you don't have one, be sure to pick up our FTDI adapter in the shop.