[Coco] Mark McDougall's CoCo 1/2 FPGA Project

[Dave Philipsen]

On 11/14/2017 5:54 PM, Mark McDougall wrote:
> On 15/11/2017 1:02 AM, Carlos Camacho wrote:
>
>> An email to Mark came back undelivered. I'm trying to reach him via
>> Facebook. Maybe he is on this list?
>
> I am indeed!
>
> Which email did you use. I think it should have reached me, unless the 
> spam filter got hold of it.
>
>> Looks like PACE used a Altium NanoBoard. I 'think' that used a Cyclone 1
>> chip? I was thinking about a bunch of EP2C5T144C8N mini board FPGAs I
>> bought to run Grant Searle's various MultiComp (i.e. 6809 version). 
>> These
>> FPGAs are super cheap on eBay. If the code for Mark's project became
>> available, maybe the VHDL code could be ported to the EP2C5T144C8N?
>
> PACE did indeed start with the Altium Nanoboard, but evolved as I (and 
> others) acquired more powerful targets. There's 'support' for quite a 
> few platforms in there, although typically not every platform 
> (emulated system) has been ported to all the supported targets. The 
> main targets are DE1 & DE2, plus a few proprietary boards I have.
>
> Bear in mind that the PACE 'framework' is exactly that; a framework 
> intended to facilitate both easier addition of new platforms (emulated 
> systems) and new targets (hardware). Thus there's a lot of 'baggage' 
> that goes with each emulation; you can't just pick out a few files in 
> one directory to build a single system. Much like MAME, for example. 
> And all this was 'experimental' at best.
>
> Having said that, the Coco1/2 emulation is fairly complete. On a 
> system with CF, for example, it's perfectly functional for an 
> end-user. However on a system with SD (not CF) the controller is 
> read-only so you can't write to the SD card, which limits its use. I'm 
> sure it wouldn't take much work now to add write support for SD... I 
> just never got around to it. The idea there was to use a back-end 
> module to have the SD 'emulate' an IDE/CF device, so that the project 
> would work on both IDE/CF and SD systems with very little change.
>
> I'm not 100% sure but if the EP2C5 board is the one I think it is, 
> then I actually have a couple that I bought for another project. From 
> memory though, there's no RAM on there so I don't think you could run 
> the Coco emulation... and perhaps not even enough on-chip memory for 
> the Coco ROMS?!? I'd have to check.
>
> Can you send me a link to the EP2C5 boards you bought?

The EP2C5 eBay boards only have about 14.5K of internal block RAM. If 
you disassembled both the CB and ECB ROMs and then re-assembled 
eliminating some stuff you don't need you *might* get them to fit but 
then you would have no memory for font tables or anything else.

I don't know what the requirements are for Pace.  In my opinion, the 
cheap eBay EP2C5T144 boards are not the best quality.  I bought several 
and was fairly unimpressed.  However, another Chinese company has very 
good quality boards albeit a bit more expensive: 
https://www.waveshare.com/product/fpga-tools/altera/core.htm

I have ordered a number of boards from them and they are excellent 
quality.  In fact, I just ordered 12 of their EP2C5T boards for some 
initial runs I'm doing.  I'm pretty sure they would have a board that 
would have enough RAM in one f their Cyclone III or IV models.



Dave

>
> The PACE code was freely available for many years but I removed public 
> access only because I wanted to use the (same) SVN repository for 
> non-public projects. I don't have a problem with providing an archive 
> of it to anyone that is interested.
>
> I haven't touched FPGAs much in the last few years as my day job moved 
> more towards software than FPGA work and I now have a young family 
> which makes it difficult to spend large blocks of time on my own 
> projects. Having said that though, I've recently been involved on the 
> periphery of a few other FPGA emulation projects and have just started 
> - literally this week - to play around with PACE again.
>
> I've still got other projects I need to finish first (eg. Asteroids 
> for Coco3) but I do plan to fiddle with a few FPGA projects, mainly on 
> the DE1, in the near future.
>
> Regards,
>