This board is designed to be used as front-end of a system. It makes possible to command 10 LED (on, off, blink, ...) and get the status of 2 switch.
This board is designed to communicate with a master device (not this project) via an UART.
Switchs status can be send to the master (via UART_TX signal) or used directly by AtMega8 to reset LED status for example.
LED status can be set in function of switchs status, and/or in function of data received via UART.
AtMega8 source code is not given because it is dependant of your application.