ZX-UNO 65 --- a ZX Uno port for the MEGA65

Zitat von adtbm

here is an example for the ZX Uno @ Mega65 - Delta's Shadow demo.

Great news! I had a Spectrum and like to see it running on the MEGA65!

adtbm : The posts in the the new section "ZXuno" are not shown in the "Last 20 posts" list. I think it is the same problem like with the "DevKit" section a few days ago?

Fixed!

I've just spotted this announcement, having just read Paul's latest blog post about supporting other cores on the MEGA65, and the ZX Spectrum in particular.

Having the ZX Uno ported to the MEGA65 is absolutely fantastic news – and I really commend Sy2002 for doing this excellent work. Thanks very much for doing this!

However, given that this has happened, I would really urge someone – Sy2002 again, perhaps? – to port the ZX Spectrum Next to the MEGA65. This really would be the ultimate Spectrum core to have. I imagine that lots of people here know about the Spectrum Next already, since it's the closest Sinclair-based equivalent to the MEGA65, but for those who don't… the Spectrum Next represents a continuation/development of the Sinclair 8-bit platform on modern FPGA-based hardware. Like the MEGA65, it too can run other cores to simulate other systems.

The Spectrum Next is better than other Spectrum clones because it has its own new hardware features and new system software, which is really nicely presented and easy to use and yet remains entirely backwards-compatible with existing Spectrum models. So it's effectively a superset of all other Spectrum models. (There are still one or two small missing features, like full support for Russian Spectrum clones and TRD disk format support within 'Next mode'… but those things are, I believe, coming, and you can already use them in a 'personality' other than the native Next mode.)

Anyway, in addition to being 100% Spectrum compatible, the Next provides many extra features including new screen modes of up to 640x256 resolution (up from 256x192), a 512-colour palette (up from 15 colours), attribute clash-free graphics, 128 hardware sprites (the standard Spectrum has none), three AY8912 sound chips (the Spectrum 128 has one, the original 48K Spectrum none)… and MANY really nice built-in extras. And its OS is hugely more capable than that of any previous Spectrum model (it's been expanded beyond recognition), yet it remains backwards compatible. Just as one small example, the Next has a lovely inbuilt file browser that works in a similar way to the esxDOS browser that comes on the ZX Uno, except that the Next browser supports both long filenames and mixed-case filenames, which esxDOS still doesn't (and which make a huge difference to usability). Plus, it simply looks a lot nicer!

The entire Spectrum Next system is open source, and there's already both an official Spectrum Next core to run on the ZX Uno, and an entire new official clone machine in the form of the N-GO: see https://ultimatemister.com/pro…ext-official-clone-board/.

Indeed, the N-GO has been highly praised and is said to be actually slightly better than the official Spectrum Next, because not only is it 100% compatible, but it has some minor hardware advantages and also has official out-of-the-box support for a ZX Uno personality, too. So an N-GO is both a ZX Uno and a ZX Spectrum Next all in one, for a very attractive price.

Anyway, the main point is that the Spectrum Next is an open source platform and its developers are keen to see it appear on other computers, whether they be new clones like the N-GO or other FPGA-based alternatives like the ZX Uno.

Finally, as well as supporting the entire library of Spectrum software, there's now a decent amount of new software being written specifically for the Spectrum Next, taking advantage of at least some of its new features. For example, the very first commercial game announced for the MEGA65, Stefan Bylund's The Curse of Rabenstein, came out for the Spectrum Next as part of the game's initial release, complete with identical graphics to the Amiga version. (And the Magnetic Scrolls adventures have already been ported with lovely Amiga graphics and high-resolution text.) But there's loads of action games too.

Notably, the video used to demonstrate this new ZX Uno port on MEGA65 uses the newly released Delta's Shadow game to show off the working Spectrum. But, interestingly, there's a much better version of that game – the developers' definitive version – which has been greatly enhanced for the Spectrum Next.

So, the Next would be the perfect Spectrum core for running on the MEGA65. It's the most complete and capable option available, and it's also open source – all very much in the spirit of the MEGA65. I'd absolutely love to see it ported, if only to take advantage of the MEGA65's wonderful keyboard. (The authentic Spectrum Next also has a very nice keyboard, actually – far better than any actual Sinclair machine – but it's still a laptop-style membrane keyboard, not the super-high-quality heavy-duty mechanical keyboard of the MEGA65.)

So, I don't mean to diminish in any way the wonderful work that's been done here, to bring the ZX Uno to the MEGA65. It's a fantastic development that I'm really pleased to see. But the absolute icing on the cake would be a port of the Spectrum Next, because that's the latest and greatest (and fully backwards compatible) state of Spectrum development, with its own growing library of new software, and it would be a perfect match with the MEGA65 hardware.

Hi adtbm,

Thanks very much indeed for this detailed response, which is far more than I was expecting! I really appreciate it, and hearing about your reasoning.

For what it's worth, although obviously I'm disappointed by the official "no" answer, I actually agree with most of the things you say, and I can certainly understand your position. But I'd just like to respond to a few points, for completeness.

First of all, I have indeed been contacted by a team member (one who I knew already, and who I know to be exceptionally knowledgeable), and he explained to me that the situation regarding the licensing/open source status was less clear cut than I had thought. When I wrote my previous post I was unaware of this: the Next team have said all along that the whole Spectrum Next platform was intended from the outset to be fully open source, and in recent times I was under the impression that everything had been released in that way already. However, I'm no legal expert, and it seems there are certain considerations that make things less straightforward than I'd imagined. That's a shame, but… I can certainly see things from your point of view.

Now, with regard to some specifics that you mention:

• I completely agree that the ZX-Uno is an excellent core to have, and certainly the next best option after the Next in terms of features.

• As you say, the main thing you lose from the Next is its new features, and the ability to run software written specifically for the Next. This is already a bit of a shame, and will of course become more so in future as more new software appears for the Next, as we hope it will (just as we hope for new software that takes advantage of the MEGA65). But at present this is indeed a minor concern.

• In fact, your ZX-Uno port – so I'm told in private – does not include support for the ZX Spectrum +3 (the model with the disk drive). So that'll be a shortcoming on the MEGA65. In reality it's of little consquence, and is considerably less important than the omission of the Next features, I think, because there's so little software exclusively for the +3. The main loss will be support for +3 disk image files, as some of them are far more convenient to use than tapes – notably for multi-load games. But this is a very minor loss.

• Concerning Russian clones… in fact, there's been some basic provision for them in the Spectrum Next for a long time, and I think it's always been something they've intended to support when other more important things were done. I'm aware that there's a new system distribution due out any day now (version 1.4 – we're currently on 1.3.2), and I believe that the 1.4 software will go a lot further in terms of Russian clone support. I've also been told in the past that support for the TRD disk formats (widely used by the Russian Spectrum community) will also be added in future, though I don't know if it's coming with System 1.4. Anyway, the point is that work continues on the Spectrum Next software, as you'd expect, and I do anticipate that support for the Russian machines will arrive in due course.

Anyway, these points are just to set the record straight! I really appreciate your detailed response, and actually I'm extremely happy that the ZX-Uno core is to be included. Obviously I'd personally like a Next option too, but I completely concur with your position that the ZX-Uno is an excellent choice that caters for the vast majority of Spectrum software out there. (The Next just has some unique features and an overall much nicer user interface.)

While on the subject of alternative cores, I'm delighted to hear that you have firm plans to release other open-source cores on the MEGA65, and I very much look forward to seeing them. I wonder if you'd consider another request, though…?

I'd personally really love to see ports of the cores for my other favourite platform, namely the Acorn machines. (Well, the 8-bit ones, obviously! The 32-bit Archimedes would be rather too demanding…!)

There are already some really excellent cores for the Acorn Atom, BBC Model B and BBC Master series machines. They've already been ported to the Spectrum Next, and the BBC Micro and Master cores (the ones of greatest interest) are particularly impressive, as they include optional Tube-based 65C102 second processors and all sorts of other built-in optional extras for the BBC series (including enhanced ULA producing more colours and new screen modes, Hybrid Music 5000 music synthesiser peripheral, mouse and SD card support and even a BBC SID chip option!). They're really fantastic cores – the best I've seen on the Spectrum Next, anyway.

The BBC cores have been ported to the Spectrum Next by David Banks ('hoglet67'), who's a very active developer of innovative hardware and software for the BBC series, and is readily available on the stardot.org.uk forums. His work has transformed the platform in recent years. (E.g. He designed the PiTube Direct, which allows you to fit a Raspberry Pi to a BBC and use the Pi as *any* of Acorn's series of second processors. And he's done much else too.) His BBC cores for Spectrum Next are available (with source code) here:

• Hoglet67's BBC FPGA cores for Spectrum Next

These cores do work superbly on the Spectrum Next… but the main shortcoming is the keyboard. It's a great keyboard for a Spectrum, but there simply aren't enough keys to provide good, comfortable support for the BBC's keyboard. In that respect, the MEGA65 would be a *much* better fit for the BBC hardware.

Additionally, the BBC was a fantastic platform, and one of the longest-lived of all the 8-bit platforms (it was still in widespread use up to the mid-90s). And, of course, it has BBC BASIC, arguably the best ever version of the BASIC programming language. Along with the Spectrum core, Acorn support is what I'd most like to see on the MEGA65 personally. Incidentally, the Master Compact came with a 3.5" disk drive, so if the BBC Master core includes Compact support (and I'm not sure if it does…), it would be able to use Acorn ADFS floppies directly, which would be handy.

I don't know what the situation is with regard to the source being open/licensing etc., but if you feel this is worth pursuing I'm sure it'd be easy to find out. Also, David Banks seems very approachable and helpful if you need his input…

Thanks again for considering my input, and for your helpful responses.

Just an observation: no-one has responded to the idea in my previous message about porting BBC Micro/Master cores to the MEGA65.

I'm wondering whether this is being given any consideration… or did I simply write too much in my last message? Maybe people skimmed the initial Spectrum bit and didn't get as far as the BBC stuff at the end!

Zitat von Richard Hallas

Just an observation: no-one has responded to the idea in my previous message about porting BBC Micro/Master cores to the MEGA65.

I'm wondering whether this is being given any consideration… or did I simply write too much in my last message? Maybe people skimmed the initial Spectrum bit and didn't get as far as the BBC stuff at the end!

I think it`s because this topic is discussed in this thread, already.

Hi adtbm,

Thanks for the response. And I'm sorry if I was seeming to push. That wasn't my intention; I was just interested to know whether anyone was actually thinking about this or not. And forgive me – I'm not really familiar with how the team is structured. There was previously talk of 'the team' porting particular cores, so I wasn't sure to what extent it was 'official' or volunteer efforts (or a mixture).

As to the "Are you interested?" question at the end…! I honestly wish I had the expertise to do the job myself, but unfortunately I simply don't.

Zitat von adtbm

So i am really sorry, if i may have sounded a bit harsh, that was definetely not my intention.

Absolutely no apology needed – I completely understand your position.

As for approaching David Banks and asking him myself… yes, I'd already wondered about doing so, but I thought I should wait for your response first because I don't want to tread on anyone's toes or complicate matters. However, now that I know you're happy for me to make an approach, I will indeed do so.

I regret not being able to help more directly on a technical level, but if I can manage to facilitate something through some polite negotiations, that would be a lot better than nothing!

Zitat von ubik

Zitat von Richard Hallas

I regret not being able to help more directly on a technical level, but if I can manage to facilitate something through some polite negotiations, that would be a lot better than nothing!

Regarding that... do you by any chance have a contact who knows about 8-bit BBC BASIC licensing? I know the 32bit ARM variant is open sourced, but so far I didn't manage to find out if that license applies to 8 bit BBC BASIC as well.

(a little bit of background: I'd love to see BBC BASIC running natively on the MEGA65 platform. And since – despite all my lobbying and pleas and reasoning – no one seems interested, I guess I'll have to do it myself Porting the BBC core so that it runs on the FPGA surely is nice and all, but it doesn't bring the MEGA65 platform forward. We need this stuff running on the MEGA65 natively, and it's definitely doable. So I'd like to do it. But first I have to know if it's legally ok to do so. There's nothing worse than spending months and months of work, only to have it screwed up by some lawyer...)

Well, I for one am definitely on your side, then! I heartily agree about BBC BASIC; it'd be a fantastic asset to the MEGA65, and I'm not sure I see the attraction for starting again from scratch with a brand-new version of BASIC when such a good one as BBC BASIC exists. Not to mention that BBC BASIC is so well established and widely used. And, of course, in its original guise it has an inline 6502 assembler which should in theory be mega-useful on the MEGA65…!

Anyway, to answer your question… to the best of my knowledge, the rights are owned by Richard Russell, who wrote the Windows, MS-DOS, Z80 and SDL versions of BBC BASIC. He also, I believe, now has some sort of Android app-maker based on BBC BASIC. And he also ran a BBC BASIC support group at one time (I don't know whether it's still on the go). I've never had personal contact with him, but his name has come up many a time and if anyone can help you in this excellent venture, it'll surely be him. I'd hope he'll prove approachable and helpful.

His website is here:

Richard T. Russell's site: BBCBASIC.co.uk

He's still selling BBC BASIC for Windows as a commercial product (£30), but he provides many other versions on his site for free, and there are still some obscure versions you can download from there (such as one for Tatung Einstein). You can get a version for CP/M for free, too.

It's worth also mentioning that third parties have already been allowed to create their own versions too… in particular, there's a version of BBC BASIC for the ZX Spectrum by Jonathan Graham Harston which can be found here. It includes Spectrum-specific adaptations. Indeed, I'd heard on the grapevine that someone had even been working on a version for the ZX Spectrum Next, though I've no idea about its status.

Anyway, Richard Russell is definitely your starting-point, and based on what I know I'm reasonably optimistic about your chances. (Famous last words…!) Good luck.

What about an Amiga Core (minimig).

I know about the Thread name, but for only one question, i don´t want to make another one.

But it is from Commodore, i know it is not from Commodore, from the amiga team.

I still haven´t a FPGA now, because everybody make cores for their own favorite system and the mega65 team had made their system on the nexys4 DDR.

I haven´t bought an FPGA till today, because if i want them all(Commodore) i need more than one.

For me the C65 is an successor of the C128 and not from the C64 and i am worry about no C128 fpga system, but it can be very useful to support the amiga core, because

1. It is from Commodore

2. A lot of Software

3. The C65 was discontinued because they bought the amiga

4. The Keyboard can handle it

5. Sinclair had nothing to do with commodore

6. It´s still unclear, if we have very good games, software etc. for the mega65, if not, we have still a stylish commodore computer, that can still run most commodore software ever written and can for many even be the cause to buy it.

Amiga Software

C64 Software

Mega65 Mode

i mean the amiga is not an 8 bit computer and the zx is, but why not.

Regarding David Banks and the potential porting of the BBC Model B and Master cores to the MEGA65…

I'm afraid I have bad news. I had a conversation with David today, and regret to say that I was unable to interest him in helping with this. (And believe me, I tried VERY hard…) Among other things, he apparently doesn't get along with the Vivado tool chain. Moreover, he says that porting cores is pretty tedious work and he'd rather spend his time on doing new projects.

I'm very disappointed by this, because his work is top notch and if he did do this port it'd be really solid. His many other projects on the BBC Micro are fantastic, too. However, he seemed resolutely against the idea, and I suspect that, having done the job once with the Spectrum Next, he simply has no appetite for doing the same thing (in effect) again.

Anyway, he would not be persuaded, I'm afraid. I shall just have to hope, therefore, that someone else with the necessary expertise will be willing to do the work in due course. On the positive side, David's source code is at least readily available, here:

BBC FPGA cores for Spectrum Next by David Banks