Date   : Mon, 06 Oct 2008 21:51:08 +0100
From   : mfirth@... (Michael Firth)
Subject: New 6502 second processors?

----- Original Message ----- 
From: "Mark Haysman" <jumbos.bazzar@...>
To: <bbc-micro@...>
Sent: Monday, October 06, 2008 9:19 PM
Subject: Re: [BBC-Micro] New 6502 second processors?


> Hi.
>
> It's something I almost started a few months ago. I had 2 projects I 
> wanted
> to get done, a remake of the 1770 DFS PCB, and a 6502 Co-Pro. I've done 
> the
> 1770 board, and sourced some VL1772s from the states. For the Co-Pro, I 
> got
> all the info I needed ready, and started scribbling about remaking the 
> ULA,
> but just got sidetracked.
>
> I was going down Michael's route, use a CPLD for the ULA and associated
> logic, then have static RAM, EPROM, etc, and a 65SC102 CPU. It would 
> depend
> on sourcing a good quantity of the CPUs, and fitting it all into cost
> effective all round solution. I'm all for breadboarding stuff up for the 
> fun
> of it, but if you have to make the expendature of having PCBs made, and
> buying obsolete ICs in quantity from a vendor, then it needs to be 
> something
> that's sellable at the right price to recover some costs. I would have
> thought using an FPGA would push the cost up too high, although it would
> allow a faster speed I suppose.
>
It looks as though new 65C02s are still being made - see:
http://www.65xx.com/wdc/w65c02s-chip.cfm

The datasheet on there is dated August 2008, so its a fairly recent website.
At around $8 US, it may well make the FPGA approach cost prohibitive, but, 
interestingly,
they do make a "Verilog RTL Core Available for FPGA Development".

> If anyone has VHDL or a schematic of the ULA already done, I'd be 
> interested
> in taking a look.
>
How different will the 6502 ULA be from what is in the PLD on the new ARM 
boards?

http://www.sprow.co.uk/bbc/armcopro.htm

I guess the other question is whether the code that's in there would be 
available, or whether its
proprietary.

Michael