Saturday, 13 February 2021

MEGA65 Devkit - First Impressions

So, here I am in February 2021, typing a blog post in GeoWrite running on a never-released Commodore prototype from 1991 - or at least the nearest thing to it. Of course, I'm referring to the still-very-much-WIP MEGA65 from the Museum of Electronic Games and Art (MEGA); an FPGA based re-imagining or continuation of Commodore's ill-fated C65 prototype.

Those of you familiar with the Commodore 65 will be well aware that the few prototype machines that leaked into the retro computer market now exchange hands for tens of thousands of pounds - absolutely crazy money for an only partially-functional computer with no software. I mean, even if I had that kind of money to burn, there honestly would be no reason for me to have one. However, unlike it's predecessor, the MEGA65 is no overpriced, lame duck. In fact, I believe that the MEGA65 has the potential to become the Commodore's answer to the Sinclair Spectrum NEXT; an enhanced, future-proof 8-Bit machine (I know, what a contradiction!) with backwards compatibility and a strong focus on 'what could have been'. After all, the C65 was a machine that sat somewhere between the C64/128 and the Amiga 500 in terms of power (you can read more about the enhanced specifications on the project web page). It's an odd beast that sits between the 8-bit and 16-bit generation machines, and reminds me a little of the SAM CoupĂ© in that regard - but with a far, far better starting point than the bloody ZX Spectrum!

I was one of the lucky few (100, to be precise) Commodore fans to obtain one of MEGA's build-it-yourself devkits that were made available to buy last year. In contrast to the final design, these devkit versions have an Amiga 600 style form factor and use a transparent plastic PlexiLazer shell (much like that used by my daily driver customised C64). In fact, this was one of the main reasons I favoured the devkit over the final design - it just looks incredible and at only 35cm wide it fits far easier on my desk.

However, good looks alone do not make a good computer - and as with the prototype C65, currently there's very little native software available for the MEGA65. That's unlikely to remain the case of course - especially if the activity on the discord channel is anything to go by. I imagine that by the time the final model rolls off the assembly line there will be a fair sized dedicated library - enough to whet people's appetites at the very least. Personally though, I had another reason to get involved with the early access of the machine - not only was I interested in testing and assisting with the final polish of the MEGA65, but I was hugely curious as to whether or not any RGCD releases (past, present or future) would run on it. In fact, I even proposed to the MEGA team that if they can improve the machine's backward compatibility to support RGCD's releases, then they can bundle them for free with their machine when it goes on sale.

As it stands, compatibility with C64 games - especially modern-era ones - is low on the current firmware. The main issue seems to involve the use of illegal opcodes; those dirty shortcuts and tricks that modern day developers often use on the C64 to squeeze out the best performance from the machine. These are especially common in demos (I have yet to find any that run on the MEGA65), and the reason is simple; these opcodes are aimed at the C64 chipset - and as the MEGA65 currently has no way to force itself to become 'the lesser' machine, the C65 CPU fails when they are called. This could (and probably will) be fixed in the majority of cases, but it will take time. So those of you were are gutted that they missed out on the devkits last year - I expect the wait for the final model will be worth it. (Edit: since writing this post the MEGA team have already got the previously non-working Super Bread Box running on the machine from cartridge, so compatibility is improving all the time!)

On the plus side, having a devkit has been a bonus for RGCD as I've been able to assist in getting some of our future releases up and running on both the C64 and the MEGA65! In particular, this past week I've been busy helping Antonio Savona and Lobo with their PETSCII brawler 'Monstro Giganto', a game that you'd think would have no issues running on a machine as powerful as the MEGA65. However, until this evening the game was full of illegal opcodes and the game pretty much crashed and burned within seconds of turning the machine on. Thankfully, Antonio was willing to rewrite these sections of his code (mainly so he can make the proud claim of releasing a MEGA65 compatible game) and now Monstro Giganto runs perfectly. This process was quite painless - even when done remotely via Facebook messenger - because of the MEGA65's excellent built in freezer and memory monitor. I was able to take a photo of the monitor screen whenever the game crashed so Antonio could see what was causing the problem and work around it.

Whilst discussing Monstro Giganto it's also worth mentioning the performance of the MEGA65's dual soft SIDs - something that is especially important considering the 250+ words of sampled speech the game contains. Honestly, the MEGA65's SID emulation is one of the best I have heard on a hardware C64 clone to date - far superior to TheC64 and cleaner sounding than the otherwise brilliant Ultimate64. So whatever the MEGA team are doing on that front, they're doing it right!

With regard to RGCD releases on the platform, there's nothing currently planned in the immediate future, but at the very least I'll be encouraging the developers I work with to support the MEGA65 going forward. Antonio has said he might look into porting P0 Snake over as an experiment, and Marcelo Cabral has suggested that he could attempt a MEGA65 version of Retaliate DX (a WIP C64 game that already works great on the MEGA) - so who knows? There might be a couple of games from us before the year is out.

One of the most interesting things about the MEGA65 is that being an FPGA based machine it has the ability to run different 'cores'. There's already a ZX-UNO core that runs on the MEGA which turns the computer into a ZX Spectrum clone, and work has begun on Atari ST and Amiga cores as well. Similar to the popular MiST FPGA, this means that your MEGA65 could eventually become your one-stop retro computer covering a variety of platforms, with the bonus of being beautifully packaged in the shell of a classic computer (and having one of the best keyboards I have ever used).

If I get time I'll happily share any new developments or interesting info about the MEGA65 here on the blog, but for now I hope that this has served as an introduction. If you want a more detailed guided tour of the machine then I strongly recommend you check out the recent video posted by Nostalgia Nerd - I really feel his pain about snapping the top part of the case during assembly!


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