The Arduino Pro Mini is a microcontroller board based on the ATmega328p. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, an on-board resonator, a reset button, and holes for mounting pin headers. A six pin header can be connected to an USB to serial adapter to provide USB power and communication to the board.The Arduino Pro Mini is intended for semi-permanent installation in objects or exhibitions. The board comes without pre-mounted headers, allowing the use of various types of connectors or direct soldering of wires. The pin layout is compatible with the Arduino Mini.There are two version of the Pro Mini. One runs at 3.3V and 8 MHz, the other at 5V and 16 MHz.Dimensions0.7x1.3" (18x33mm)FeaturesATmega328 running at 16MHz with external resonator (0.5% tolerance)0.8mm Thin PCBUSB connection off boardSupports auto-reset5V regulatorMax 150mA outputOver current protectedWeighs less than 2 grams!DC input 5V up to 12VOn board Power and Status LEDsAnalog Pins: 8Digital I/Os: 14DocumentsSchematicEagle FilesGetting Started Tutorial