Adafruit Metro Mini 328 V2 - Arduino-Compatible - 5V 16MHz - STEMMA QT / Qwiic

The V2 is a significant redesign, enough, so we consider it a completely new product. It still features the ATmega328 chip and is drop-in compatible with the original METRO Mini, but has many upgrades and improvements:

• Same ATmega328 chip, running at 16 MHz, which makes it compatible with all Arduino UNO based libraries, codes and examples
• Same pinout and size, same mounting hole locations - drop-in compatible!
• Additional STEMMA QT port for plug and play I2C connections
• USB Type C port instead of Micro B
• Upgraded USB to serial converter from CP2104 to CP2102 - same great reliable drivers!
• Can still be set to use 3.3V power and logic by soldering a jumper on the bottom.

METRO Mini V2 is the culmination of years of playing with AVRs: we wanted to make a tiny, breadboard-friendly development board that is easy to use and has a STEMMA QT port for plug and play support with hundreds of devices. Metro Mini can be programmed with the Arduino IDE (select 'UNO' in the boards dropdown)

• ATmega328 brains - This popular chip has 32KB of flash (1/2 K is reserved for the bootloader), 2KB of RAM, clocked at 16MHz
• Power the METRO Mini with 6-16V polarity protected on the Vin pin, or plug the micro USB connector to any 5V USB source.
• METRO has 20 GPIO pins, 6 of which are Analog in as well, and 2 of which are reserved for the USB-serial converter. There's also 6 PWMs available on 3 timers (1 x 16-bit, 2 x 8-bit). There's a hardware SPI port, hardware I2C port, and hardware UART to USB.
• GPIO Logic level is 5V but by cutting and soldering closed a jumper on the bottom, you can easily convert it to 3.3V logic
• 5V onboard regulator with 150mA out, separate 3.3V 500mA regulator is also available.
• USB to Serial converter, there's a genuine SiLabs CP2102N hardware USB to Serial converter that can be used by any computer to listen/send data to the METRO, and can also be used to launch and update code via the bootloader
• USB C power and data
• Four indicator LEDs, on the top of the PCB, for easy debugging. One green power LED, two RX/TX LEDs for the UART, and a red LED connected to pin PB5 / digital #13
• Easy reprogramming, comes pre-loaded with the Optiboot bootloader
• Beautiful styling by PaintYourDragon and Bruce Yan, in Adafruit Black with gold plated pads.

The Metro Mini comes as a fully assembled and tested board, with bootloader burned in and also some 0.1" header. Some light soldering is required if you'd like to plug it into a breadboard, or you can solder wires or header directly to the breakout pads. Once headers are installed they can be fitted into 0.6" wide sockets

Technical Details:

• ATmega328 microcontroller with Optiboot (UNO) Bootloader
• USB Programming and debugging via the well-supported genuine SiLabs CP2102N
• Input voltage (Vin): 6-16V (a 9VDC power supply is recommended)
• 5V logic with 3.3V compatible inputs, can be converted to 3.3V logic operation
• 20 Digital I/O Pins: 6 are also PWM outputs and 6 are also Analog Inputs
• 32KB Flash Memory - 0.5K for bootloader, 31.5KB available after bootloading
• 16MHz Clock Speed
• Adafruit Black PCB with gold plate on pads
• JST SH 4-pin STEMMA QT port for plug and play I2C connections
• Derivative of "Arduino UNO R3 Reference design" 
• Open source hardware files on github!
• Fritzing object in the Adafruit Fritzing Library
• ATmega328P product page
• Product Dimensions: 44.3mm x17.8mm x 4.9mm
• Product Weight: 3.4g