Designed to be easy-to-use and hacker friendly, the METRO 328 has the Optiboot Bootloader already installed, which is supported by the Arduino IDE (Integrated Development Environment).
The METRO 328 can be powered either by 7V to 9V polarity protected DC voltage, or by the micro USB connector from any 5V USB source. The 2.1mm DC jack has an on/off switch next to it for simple configuration, and the METRO will automagically switch between USB and DC.
The METRO 328 has 19 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 (1x 16-bit and 2x 8-bit). The METRO 328 also features a hardware SPI port, hardware I2C port, and hardware UART to USB. The Logic Level is preset to 5V, but can be configured to 3.3V via jumper.