To the electronic "wizards" here

A place to discuss everything Dragon related that doesn't fall into the other categories.
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Vato
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To the electronic "wizards" here

Post by Vato » Fri Feb 27, 2015 9:43 pm

I have been away from the retro-computing "scene" (Dragon/Amstrad) for some years now, and I'm amazed to see all the various new hardware that's been developed for both my computers at heart. Really??? ... we have the possibility to use micro-SD for storage now, using the uDW made by Tormod? That's just amazing.

I have also been checking up the "dark side", aka. Amstrad CPC, and the progress made in hardware development at that front, and this wonderful thing came to my attention:
http://www.cpcwiki.eu/forum/amstrad-cpc ... cpc-board/

If you don't want to read through the entire thread, here's a short summary:
It's a new Amstrad CPC motherboard, with a new form factor, and many built in enhancements like expansion ports, floppy controller etc etc. You can easily swap ROMS, use various mass-storage devices, and the new expansion ports are fully documented, so that you can easily make your own expansion devices. But best of all, you can fit the thing in a reasonably sized case, hook it up to your monitor, power supply and PC-keyboard!

and here's a YouTube video:
https://www.youtube.com/watch?v=51Iymj_V_aY

What if....
I'm dreaming of a redesigned Dragon board that could be fitted inside a ITX or mini-ATX case, with cartridge-, parallel-, RS232-, joystic-, monitor, and tape ports. Maybe the floppy controller, the uDW could be "built in"?

Is this even possible, a Dragon stacked on top of your Mac-Mini or Intel NUC?

Tom
Tom

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robcfg
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Re: To the electronic "wizards" here

Post by robcfg » Fri Feb 27, 2015 10:23 pm

Hi Tom!

Another CPCWiki contributor here :mrgreen:

The issue with the new CPC board is that the inners of the Gate Array are basically unknown so an implementation of an Amstrad CPC on a FPGA or CPLD is not possible (for now). There was one, the C-One or CPC T-Rex, but obviously you cannot guarantee the exact operation without fully understanding all the parts.

That said, the Dragon is much easier as it doesn't have custom parts, and something like the One Chip MSX, should be quite doable.

Also, on the spanish http://www.zonadepruebas.com forums, a group of people is creating the ZX-Uno, which is a Spectrum clone with many enhancements, in a Raspberry Pi form factor. (Some pictures here).

I like the idea of something on the line of those two. More like the One Chip MSX if you like to use the original cartridges and other peripherals, and more like the ZX-Uno if you'd like to go for a more compact solution.

Vato
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Re: To the electronic "wizards" here

Post by Vato » Fri Feb 27, 2015 11:10 pm

Rob,
Thanks for the info, and nice to see a fellow Amstrad user here!
I see there are several 6809 FPGA projects going on. I have minimal (as in zero) experience with this kind of stuff, but I understand that a FPGA-board like the NEXYS4 (http://www.digilentinc.com/Products/Det ... rod=NEXYS4) could be used to run some kind of "virtual implementations" of various chips and CPUs to make up a complete computer, like the Amstrad CPC made by Renaud Hélias: https://www.youtube.com/watch?v=NRJMsU_9g5w, or the mentioned One Chip MSX. I see the board has many external ports, including one analog. A Dragon based on such a board would be cool. I guess it would be possible to use the external ports to connect joystics (analog), and maybe even make a cartridge port as well?

Just thinking out loud here, hoping someone with the "know-how" might take the bait ;-)

Tom
Tom

sorchard
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Re: To the electronic "wizards" here

Post by sorchard » Sat Feb 28, 2015 3:09 pm

An FPGA Dragon is one of those things on my long term todo list. I bought a development board years ago to learn the art (http://www.xess.com/shop/product/xsa-3s1000/) and did a number of cool things with it.

The learning curve is a little steep but it's not rocket science and I think there are a number of people on this forum who could tackle something like this. For me the big part of the job is creating a cycle accurate 6809 core. To my knowledge this hasn't been done yet and most people seem to be content to use John Kent's excellent 6809 core e.g. Gary Becker's Coco3FPGA.

The big development boards are good value, but perhaps a little expensive for the hobbyist. All you really need is a board with FPGA, external memory and a programming interface like one of these: http://www.xess.com/shop/product/xula2-lx9/

To add interfaces for things like displays and keyboards, buy a bag of jumper leads and take your pick from the vast number of cheap add-on boards available from hobby suppliers and ebay.

There are quite a few fpga boards on ebay that are cheap and ideal for learning, the only snag being that the cheaper ones won't be big enough to hold a Dragon. The 6809 based system I was playing around with (before my son was born and suddenly all free time disappeared) used up about 30% of the LUTs and most of the SRAM on my million gate Spartan3. I reckon a Dragon 32 would use slightly less than this and would fit comfortably in the Spartan6 LX9.

I'm happy to share what I've learned with anyone willing to take the plunge, but it'll be a while before I could spend some serious time on a new project. I've often amused myself with the thought of a tiny Dragon, half size but fully functional and compatible. Maybe one day...
Stew

Vato
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Re: To the electronic "wizards" here

Post by Vato » Sat Feb 28, 2015 6:09 pm

Thanks for the input, sorchard!

What do you experienced people feel would be the most doable solution? Using FPGA, or making a redesigned, smaller board with a mix of old and newer components?

Tom
Tom

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robcfg
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Re: To the electronic "wizards" here

Post by robcfg » Sat Feb 28, 2015 8:06 pm

Looking at how well the OneChipMSX works, I'd go for something similar.

sorchard
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Re: To the electronic "wizards" here

Post by sorchard » Sat Feb 28, 2015 9:20 pm

I agree with robcfg, an fpga based solution appeals to me. The majority of the design effort would be contained in the HDL files describing the logic and these could be ported relatively easily to any suitable platform, including existing development and homebrew boards.

A faster 'time to market' could be achieved with a combination of a real 6809 and programmable logic but this would not be as flexible or future proof. It would still be a cool project though :-)
Stew

Vato
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Re: To the electronic "wizards" here

Post by Vato » Sat Nov 07, 2015 11:51 am

Just found this on FB :ugeek: It's called CoCo on a Chip, and it's a FPGA implementation and expansion board for everything CoCo. IDK if it's been posted here before:

https://www.facebook.com/groups/399411586924305/

I asked the chap if it would be possible for him to do a Dragon implementation as well, something he answered positively to, if there was enough interest. So go over there, and show your interest! :mrgreen: Maybe finally I can get my long wanted "micro Dragon".......
Tom

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tormod
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Re: To the electronic "wizards" here

Post by tormod » Sat Nov 07, 2015 12:57 pm

The link requires registration :(

Is it the CoCO3FPGA being discussed on the CoCo mailing list? Or Roger Taylor's DE0 project that I have also seen mentioned? Or Mark's Pacedev.net / CooCoo project*?

*) http://comments.gmane.org/gmane.comp.ha ... coco/76592

Vato
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Re: To the electronic "wizards" here

Post by Vato » Sat Nov 07, 2015 6:12 pm

It's the DE0-nano by Roger Taylor

https://www.youtube.com/user/cocotower/videos
Tom

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