This Pro Mini version is 100% compatible with the original Arduino Pro mini. We add two analog IO - A6, A7 , and Power Input side add auto recovery insurance, and be allowed USB and Power Supply at same time.
it is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 8 analog inputs, an on-board resonator, a reset button, and holes for mounting pin headers. A six pin header can be connected to an FTDI cable or USBSerial Adapter to provide USB power and communication to the board.
This is a 5V Arduino running the 16MHz bootloader (select 'Arduino Duemilanove w/ 328' within the Arduino software). Arduino Pro Mini does not come with connectors populated so that you can solder in any connector or wire with any orientation you need. We recommend first time Arduino users start with the Crowduino or Arduino Duemilanove. It's a great board that will get you up and running quickly. The Arduino Pro series is meant for users that understand the limitations of system voltage (5V), lack of connectors, and USB off board.
ATmega328 running at 16MHz with external resonator (0.5% tolerance)