new Member Spain

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retrocant
Posts: 9
Joined: Sat Jul 24, 2021 2:02 pm

new Member Spain

Post by retrocant »

Greetings, my name is Alfredo and people in Spain know me better as retrocant.
I have been in the retro world for more than 4 years and they have a good collection of 8, 16 and 32 bit microcomputer equipment.
Already in the 90's I knew the dragon computer through computer science books and now I currently have several dragon computers (dragon 32 and 64) and a tandy coco 2 (64k ram), I have already done enough tests with it and they really seem very interesting computers and more with its OS-9 operating system, which I have been working with for many years with the Linux environment and community, but it really attracts me much more such computers with OS9, apart from the operating system, I have also carried out many tests with Drivewire4 and PyDrive .

In peripherals I also have, CoCo-SDC and floppy drive controller, very interesting project and very essential to be able to work with these computers.

Now I have in mind to make a pcb to be able to work in RGB mode with Dragon computers, and I hope to have help and support in this forum.
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robcfg
Posts: 1375
Joined: Sat Apr 04, 2009 10:16 pm
Location: Stockholm, Sweden

Re: new Member Spain

Post by robcfg »

Welcome to the Archive!

It’s nice to have you here. Don’t hesitate to ask whatever you need.

Cheers,
Rob
Azerpy
Posts: 36
Joined: Tue Apr 09, 2019 1:16 pm
Location: France Pyrenées

Re: new Member Spain

Post by Azerpy »

Hello Alfredo.
For your RGB project, you can look at the Dragon SECAM schematics that I have posted in the Dragon hardware section.
That Dragon SECAM has a RGB output.
Gérard / Azerpy
pser1
Posts: 1465
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: new Member Spain

Post by pser1 »

Hello Alfredo,
welcome!
Glad you have joined this group!

cheers!
retrocant
Posts: 9
Joined: Sat Jul 24, 2021 2:02 pm

Re: new Member Spain

Post by retrocant »

thanks pser1.
pser1
Posts: 1465
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: new Member Spain

Post by pser1 »

Hello Alfredo,
In case you are going to run a small batch of these VGA modules for the Dragon, I would like to buy one.
For what I have read/seen in this thread, I asume that the module should be placed in the MC6847 space, so
it will be mandatory to take it out and put a socket there, right?
The output seems to be RBG plus sync. Will these signals be correct to go to a SCART connector?
thanks in advance
cheers!
pere
retrocant
Posts: 9
Joined: Sat Jul 24, 2021 2:02 pm

Re: new Member Spain

Post by retrocant »

Greetings pere, it is correct in what you say in the signal output, RGB + sync.

The part about the location of the pcb, my initial intention was to connect it directly to the vdg, but yesterday I realized that it had no socket. I had the idea that it had a socket since my American tandy 2 computer, if it has a socket, my mistake was to imagine that the dragon computers had a vdg socket, which is not the case.

I have to give it another turn to be able to connect it in the vdg (I keep you informed of it). I am also looking at the power supply issue that is needed - 5 volts, which the dragon64 does not have, but if it has -12 volts, I have to study if I put a 7905 linear regulator starting from the line that I comment. I also study putting an LM358 comparator, but the most important thing is that we are finalizing this project with the help of azerpy.
pser1
Posts: 1465
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: new Member Spain

Post by pser1 »

Hi Alfredo,
you are right, not all of the Dragons have the MC6847 socketed, none of mine do have it. But my Tano from USA has it!
I know that it is a dangerous/risky work to cut the pins of the 6847, clean everything up and then
put a socket, but this is mandatory for instance if you want to use the nice module named CoCo-VGA
and even John Whitworth sells a module to put in that socket so that your Dragon can use the "Dragon 200" fonts
And there could be other projects that would require that socket to be there ...
So I am planning, if I dare, to do that change one of those days. I am saying so since a lot of time and never have the time to do that ;-)
cheers
pere

Ps This RGB module would be a very important complement to John's new module with the old MSX2+ chips inside.
It accepts an input from any RGB source and we could switch from one to the other by software with a single POKE
retrocant
Posts: 9
Joined: Sat Jul 24, 2021 2:02 pm

Re: new Member Spain

Post by retrocant »

Greetings pere, personally I am in favor of putting a socket to the vgd chip, but certain people can choose whether they want to put it or not, there are also certain users who do not know how to desolder, and the final decision of each one must be respected.

With which I am considering the possibility of creating a unique pcb and choosing the connection of the pcb, that if it will have somewhat average measurements having that double footprint, as I refer double footprint to click it in vdg with socket or through pads and wire it internally.

The subject of the msx2 + project I already do not know a bit how it goes, forgive me but I am not up to date, you tell me that you would like to unify both projects to select or switch said signals with rgb output between them and switching it by soft selection through POKE, if so it would be a great idea ..

It also requires that to finish the pcb the project would be in beta because it would be to generate said pcb and know if it is 100% functional or readjustments.

In short, I will do the pcb again, generating a double selection fingerprint, this being beta.

unification dragon msx2 + and rgb vdg (alpha.)
pser1
Posts: 1465
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: new Member Spain

Post by pser1 »

Hello Alfredo
what I wanted to say was that your RGB module will be a nice companion to John's module,
but I was not talking about unifying projects ...
Anybody that would buy John's new module would decide if an RGB could be worth for her/his purposes.
John has provided circuitry that accepts the RGB input as well as the V9958 signal and added capability to
select which one we want to send to the screen. That's all.
I, for one, would like an RGB module because that way I will be able to test this feature on John's module
and so, I could make programs switching video input if it were needed
In the past there was an RGB or VGA module designed by Phill Harvey Smith but it seems that it is no more
possible to get/buy one of them. So your module could be a goog choice for people searching for his module (me!)
cheers!
pere

Ps If you wanted to talk more about your project, we might switch to Retrowiki where you could open (if not yet done)
a thread to explain what you are planning to do ... just to not bother other people here.
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