Using a Ricoh 2A03 instead of a 6502/6510

[DLN-003]

Basically, is it possible to build a computer with the Ricoh 2A03 (RP2A03G/H) instead of building one with a 6502/6510? Given the 2A03 is essentially a "clone" 6502 (lacking BCD mode but I see no need for that) how feasible would it be to use this in place of a 6502 in a 6502 computer project?

[DerTrueForce]

If you could get hold of one, then it could be done.
There's a pinout here: https://wiki.nesdev.com/w/index.php/CPU ... escription

[BigDumbDinosaur]

DLN-003 wrote:

Basically, is it possible to build a computer with the Ricoh 2A03 (RP2A03G/H) instead of building one with a 6502/6510? Given the 2A03 is essentially a "clone" 6502 (lacking BCD mode but I see no need for that) how feasible would it be to use this in place of a 6502 in a 6502 computer project?

Why bother?

[Tor]

Well, why not? If DLN-003 has one laying around, by all means, go for it. Many people have some old parts laying around, and it can be fun to use them for something. And even if you don't have the parts already it could be interesting. For nearly all of the computers described&built on this forum it's not about usefulness or being easy, it's about making something that works, from a set of parts. New or old.

[DerTrueForce]

I'm sorry I didn't realise this sooner, but:
Welcome, DLN-003, to our 6502 world!

[Dr Jefyll]

The 2A03 includes on-chip some I/O devices for audio and other functions. Presumably it's both the I/O and the CPU which are important in this case.

In another thread, Aaron describes a project whose focus is the 2A03's I/O only, driven by an Arduino. (The 65xx CPU does play a role, but only as a middleman.)

ps - yes, welcome, DLN-003 !

[commodorejohn]

Yeah, I'd love to hear what the project is here. Certainly there's enough fun to be had with the 2A03's audio facilities

[DLN-003]

commodorejohn wrote:

Yeah, I'd love to hear what the project is here. Certainly there's enough fun to be had with the 2A03's audio facilities

I chose the 2A03 over the 6502 mainly because trading in BCD mode for a built in APU is totally worth it (my opinion), and it'll probably be another DIY computer running ehBASIC, but I haven't found out what video chip I should use (considered the PPU (2C02)), and I don't think this would get any far as multiple units of this, as the 2A03 is limited in stock (unless someone made a straight up transistor for transistor clone).

[barrym95838]

DLN-003 wrote:

I chose the 2A03 over the 6502 mainly because trading in BCD mode for a built in APU is totally worth it (my opinion), and it'll probably be another DIY computer running ehBASIC ...

You will need to patch a small part of EhBASIC that uses BCD mode, but it is a very minor modification, IIRC.

viewtopic.php?f=2&t=3164&p=36231&hilit= ... bcd#p36231

Quote:

... but I haven't found out what video chip I should use (considered the PPU (2C02)), and I don't think this would get any far as multiple units of this, as the 2A03 is limited in stock (unless someone made a straight up transistor for transistor clone).

Full steam ahead! We're all rooting for you, even the grumpy ones among us!

Mike B.