{"title":"Adafruit METRO 328 with Headers [ATmega328]","handle":"adafruit-metro-328-with-headers-atmega328","url":"/products/adafruit-metro-328-with-headers-atmega328","description":"The Adafruit METRO 328 is a fully assembled, Arduino UNO R3-compatible development board powered by the ATmega328P running at 16 MHz. It's shape and pin-compatible with Arduino UNO R3 shields, and works directly with the Arduino IDE by selecting \"Arduino UNO\" in the Boards menu. This version comes with through-hole headers pre-soldered — for a slimmer profile, see the METRO 328 without Headers.\n\nThe METRO is the result of years of AVR development experience, designed to be both easy to use and hacker-friendly. It features an on-board USB-to-serial converter, polarity-protected DC jack with power switch, and comes pre-loaded with the Optiboot bootloader.\n\nKey Features\n\n\nATmega328P @ 16 MHz – 32 KB flash, 2 KB RAM with Optiboot bootloader pre-installed\n\nArduino UNO R3 Compatible – Works with UNO shields and the Arduino IDE (desktop and cloud)\n\n19 GPIO Pins – Including 6 analogue inputs and 6 PWM outputs across 3 timers\n\nHardware SPI, I2C & UART – Full serial communication support\n\nUSB-to-Serial Converter – On-board CP2104 for programming and serial monitoring\n\nFlexible Power – USB or 7–9V DC with polarity protection and auto-switching\n\nOn/Off Switch – Conveniently located next to the DC jack\n\n5V Logic (3.3V Optional) – Cut and solder a jumper to switch to 3.3V logic\n\nFour Indicator LEDs – Power (green), RX/TX (yellow), and pin 13 (red)\n\n\nIdeal For\n\nArduino projects requiring UNO R3 shield compatibility\nBeginners learning microcontroller programming\nPrototyping with the Arduino ecosystem\nProjects needing a reliable, well-documented ATmega328P platform\n\n\nPackage Contents\n\n1× Adafruit METRO 328 board (with headers pre-soldered)\n4× Rubber bumper feet\n\n\n\nTip: Need something smaller? Check out the Metro Mini 328 V2 for a compact breadboard-friendly option, or the Trinket M0 for a tiny CircuitPython-compatible board.\n\n\n\nNote: Mac and Windows users may need to install the CP2104 VCP drivers from Silicon Labs for the serial port to appear correctly.\n\n\nResources\n\nOptiboot Bootloader (GitHub)\n","vendor":"Adafruit","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":9359,"title":"Default Title","sku":"AF-2488","price":34.14,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":4,"option1":"Default Title"}]}