The nano's pin layout works well with the Mini or the Basic Stamp (TX, RX, ATN, GND on one top, power and ground on the other). The Arduino Nano Microcontroller can be powered via the mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source. The package contains only the microcontroller.

Features:
• Automatic reset during program download
• Power OK blue LED on the bottom
• Green (TX), red (RX) and orange (L) LED
• +5V to AREF jumper
• Auto sensing/switching power input
• Small mini-B USB for programming and serial monitor (cable not included)
• ICSP header for direct program download
• Power OK blue LED on the bottom
• Standard 0.1" spacing DIP (breadboard friendly)
• Manual reset switch

Specifications:

• Microcontroller: Atmel ATmega328
• Operating Voltage (logic level): 5 V
• Input Voltage (recommended): 7-12 V
• Input Voltage (limits): 6-20 V
• Digital I/O Pins: 14 (of which 6 provide PWM output)
• Analog Input Pins: 8
• DC Current per I/O Pin: 40 mA
• Flash Memory: 32 KB (of which 2KB used by bootloader)
• SRAM: 2 KB
• EEPROM: 1 KB
• Clock Speed: 16 MHz
• Dimensions: 0.70" x 1.70"