Generally speaking – computer is a device that can perform arithmetic and logical operations. In other words there mas be a processor, memory and some input/output. So not only personal computers, tablets and other stuffed devices can be called computers. Any microcontroller like AVR is already a computer in a chip. Anyway for some fun, rovku put together a simple computer out of three chips that make it tick. For a processor he’s chosen Rockvel R6502P which is an 8-bit processor running at 1MHz. As I/O controller there is an Atmega16 used which talks to external CY7C130 dual port 1K RAM and also generates composite video signals.
Computer doesn’t do any special – it outputs OK to screen and blinks a cursor. But this is more than enough to prove the concept and have a warm feeling of seeing it working.