Hi Bryan,You are tackling something big: as much as I can remember, the original MOS technology 6502 was a power-hungry NMOS device which memory cells (registers, program counter, status reg) were dynamic cells to reduce transistor count. That imposed a minimum clock frequency. Being an ancient device, I wonder if electrical schematics do exist at all or if the engineers just created the chip by drawing the required photographic masks. Rather than contemplating a mess of transistors, I'd rather go for the logic diagrams which break the microprocessor into its major components: registers, ALU, buses and instruction decoding logic. The latter is probably the most complex component.
The problem with studying the 6502 is that you will miss all the 'C02 and 16-bits instructions implementation. You'll have to ask Western Digital for data on the 65816 and I'm not convinced they are willing to give freely that kind of info. Based on personnal experience, I don't think they will: in a related case, I asked Futaba for schematics to troubleshoot a defective, obsolete 1991 R/C model airplane radio receiver and my request was politely denied. From there, I decided to dump the whole set to the recycle bin :(. I whish companies would be more open about their obsolete technologies (Apple, do you hear that about GS/OS sources? :-)
An approach I was considering is to have a modern, insanely fast RISC processor to emulate a 65816 then scale up the architecture to 32 bits rather than picking up where WD has left.
Bryan Parkoff wrote:
Do you know where can I find schematic that is INSIDE 6502 CPU only, but
not for Apple II motherboard. I will be able to study how 6502 CPU work.
It is my goal to build CPU that will support 32 bits and 64 bits like
65832 and 65864. All PCI slots, AGP slots, DIMM, and all modest hardware
will be designed with new CPU in a motherboard. It is like restoration for
Apple II with 32 bits and 64 bits.
What do you think about my idea? I feel bad that PowerPC will be out of
business very soon and Apple Computer, Inc does not have choice but have to
port Mac OSX to Intel, but I tell them to design their own CPU -- 65832 or
65864. It will profit with great sales at lower costs.
--
Yours Truly,
Bryan Parkoff
BParkoff@satx.rr.com