Here is an open source ATmega325 development board designed by Dilshan. The board includes a crystal oscillator circuit for the MCU, a MAX232 serial driver, hardware reset button, and breakouts for all the MCU pins.
This post is about simple Atmega325 development board which I was designed and build to test some large AVR systems. This development board contains ATmega325 MCU and MAX232 base RS232 driver/receiver unit. Thanks to SMD packages and components dimensions of this board get limited to 85mm x 62mm. This development board requires 5V external power supply and all its external circuitries (RS232 driver and hardware CPU reset) can be enable/disable through on-board jumpers.