Welcome to my private Homepage about my Computer Projects using the 65816 CPU

Since my early youth I am engaged with electronics and since the beginning of 80ths with computers.

My first own complete computer was an Ohio Scientific Superboard. This computer was ideal for do-it-yourself enthusiasts, as it was delivered with all schematics and besides made an expansion port available, which could be used in an easy way to add own supplements. About at this time the electronics magazine Elektor developed and published the Junior-Computer, a do-it-yourself home computer, which used the same processor as the Superboard: the 6502. Both systems were quite similar, so I was able to build an interface between the bus system of the Junior-Computers and the expansion port of the Superboard. From now on I could use all further add-on cards of the Junior-Computer for the Superboard, too.

At the end of the 80ths I turned my interest mainly to the technique of IBM compatible computers, which grew rapidly that time and I left the 6502 aside. My interest again was mainly hardware and systems programming in assembler. During the first years it was rather simple, to implement own ideas in hard- and software for the PC, the rapid further development of PC technique and the available interfaces made it more and more complicated for an home enthusiast, to get the necessary information.

About that time I found Mike Naberezny’s web site 6502.org and discovered, that there are still enthusiasts all over the world who are engaged with 6502-computers. That motivated me to design a computer based on the 65816, a successor of the 6502 with expanded capabilities. This PC65816 V1 consisted besides the CPU and 2 VIA chips of many TTL parts. As RAM I used cache memory of an old PC motherboard. The computer was functional, but I missed some important functions during the development of a suitable operating system, as for instance hardware support for virtual memory.

This led to the development of the PC65816 V2. This computer is designed using CPLDs, which reduced the number of parts and offered the possibility to fit the design subsequently within limits. The computer has 4 MB RAM, a keyboard controller, a text oriented CRT controller, an ethernet controller, an IDE controller with built-in direct memory access control and a real time clock. In addition the circuit contains a memory controller for virtual memory management and all relevant i/o devices can cause interrupts. A VIA 6522 offers additional functionalities. At the moment I am working on an operating system for the PC65816 V2.