MEGA65 FORUM

WHAT MICROPROCESSOR ?

append delete Dan Laskowski

What is under the hood? Another Intel or AMD chip running VICE ?

Dan

Will this fully support the Expansion port and Cartridge slot? My MIDI interface uses these.

Thanks

Dan

http://musicinit.com/fastfingers.php

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append delete #1. gardners

The MEGA65 uses an FPGA implementing an enhanced 6502 processor, the 45GS02, that supports all the instructions of the C65's 4510, as well as being able to switch to 6502 mode, where we intend to have full illegal opcode support. The CPU currently supports 1MHz, 2MHz, 3.5MHz and 40MHz modes (the final top speed may vary around that 40MHz point. It was 48, then 50, now currently 40. The final decision will be made soon before release, when we have timing closure and exact FPGA part selection nailed down).

There is no "modern" processor. Just pure 8-bit. i.e., the MEGA65 is very different to the C64 Mini, for example.

Paul.

append delete #2. Dan Laskowski

Very interesting. THANK YOU.

append delete #3. pad00100

Outstanding ! C64 running on 40MHZ! We can imagine what DemoScene Masters will do with that power ! :D ..I have one question about CPU speed.. What is possible maximum CPU speed which we could have on FPGA implementation ? I know that 40MHZ is enough.. but ..If we could have 100MHZ or more.. that will be more and more great ;)

append delete #4. gardners

It is really all a question of work. I believe 100MHz - 150MHz would be possible. Moreover, that would be with a pipelined (but not speculative) CPU that would be able to dispatch one instruction almost every cycle, compared with every ~3 - 4 cycles in a standard 6502. Thus it would be something like 3x clock speed and 3x instruction throughput, so would be getting close to 10x faster than the current CPU.

But that will definitely not be happening before the MEGA65 is released for sale.

Paul.

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