The classic MOS6502 fascinated me for a long time. In Poland It was never quite popular among the electronics hobbyists in the eighties and the early nineties. Zilog Z80 was much more common in amateur projects back in the days. So I was a little bit intrigued, when I discovered that huge amount of original MOS6502 is available on popular Chinese auction site. Initially I suspected there are probably broken or counterfeit parts, but out of puer curiosity and due to low proce I decoded to order a couple of them, not thinking much about it.

One month later, when I almost forgot about my order, the package containing CPUs finally arrived. I spent few hours building simple test circuit on the breadboard, to check if they are real 6502s. To my pleasant surprise, they were!

So, my another project began. I designed, etched and soldered base PCB containing CPU, clock generator, on power reset circuit, 64kB of RAM (32kB accessible directly and another 32kB visible as four 8kB banks), 16kB of EPROM memory and simple address decoding logic. there is also an address bus buffer (2x 72HCT245) and single output port for LED blinking (74HCT373).

The board is compatible also with parts designed for the Intel bus, I was able to connect it to the 8251 and 8253 chips installed on the breadboard, using them to run EhBASIC. Now I need to design another board with all needed I/O components: UART, GPIO, kayboard and CRT controller, maybe even RTC.

My 6502 retro controller board was in fact an offshoot of this project.