Adafruit Metro 328 with Headers - ATmega328

Key Features: ATmega328 microcontroller with Optiboot (UNO) Bootloader A fully assembled and tested microcontroller and physical computing board with through-hole headers attached 32KB of flash and 2KB of RAM, running at 16 MHz Compatible with "Classic" and "R3" Shields This is the Adafruit METRO Arduino-Compatible - with headers. The METRO works great with the Arduino IDE, and runs the ATmega328P at 16MHz so it is shape and pin-compatible with Arduino UNO R3 shields and boards. You can use this with the Arduino IDE (both desktop and cloud version) by selecting 'Arduino UNO' in the Boards menu. The processor has plenty of GPIO, Analog inputs, hardware UART SPI and I2C, timers and PWM galore - just enough for most simple projects. METRO is the culmination of years of playing with AVRs: it's a development board that is easy to use and is hacker friendly.Power the METRO with 7-9V polarity protected DC or the micro USB connector to any 5V USB source. The 2.1mm DC jack has an on/off switch