Believe it or not, this board is a small development system. It barely fits on your finger, but it features ATmega328, USB-UART, reset circuit and LED indicators. The MINI-AT Board - 5V is compatible with standard DIP26 sockets. The onboard voltage regulator allows the board to be powered directly from the USB cable. It features a 16MHz SMD crystal oscillator.
Both come preprogrammed with a fast UART bootloader with 57600 bps operation, so no external programmers are needed for development.