Also known as CVAVR or simply CodeVision. This compiler is written by Pavel Haiduc of HP Infotech S.R.L. It is a full development system for the AVR series, available in two versions - the full version which generates code for the entire AVR Classic and Mega series', and the 'Light' version which will only generate code for the AVR Classic series (ie. part numbers beginning with AT90S....). There is support for devices with no SRAM (ie Tiny AVRs and the AT90S1200). There is an evaluation version of Codevision available free for download from the Codevision website which is limited in the size of program which it will compile. The size limit still allows a fair evaluation & may be all you need for a simple robot.