TVC ugyanaz EXTCOL \ és EC0, EC1, EC2, EC3 jeleket.

Milyen interface ez?

Külső színbemenet, ugyanúgy mint az EP-n

Volt gyakori, hogy a korszak?

Nem hinném. De az EP-t és a TVC-t ugyanaz a csapat tervezte.

Tud elérjék a Sprite prototípus?

Csak a neten lévő képeket ismerem


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TVC has the same EXTCOL\ and EC0, EC1, EC2, EC3 signals.

What kind of interface is it?

External color input, same as on EP.

Was it common on that era?

I don't think it. But same team developed the EP and TVC.

Can you reach the Sprites Prototype to study it?

I only know the photos on the net about it

Are there available any schematics ? I read that this computer has been built entirely without the use of specialized chips. I could try to clone it.
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Vannak-e rendelkezésre olyan rajzok? Azt olvastam, hogy ez a számítógép épült teljesen használata nélkül speciális chipek. Megpróbálhatnám klónozza azt.

Well, it's Hungarian book, but there are many hw related info and some "bit abstracted" schematics too (with description how it works, but in Hungarian ...):  http://tvc.homeserver.hu/doc/konyvek/tvchardver.pdf However this is not exactly a precise schematics you would expect, I think! I'm not sure if there is a detailed, full-featured schematics on the computer ...

Btw, if you want to clone, there is another - even more simple - Hungarian computer, the "Primo" (and it's b&w, the advanced colour model was not even released later but planned, if I know well) which does not even use "complex" chips (other than the Z80/U880, U880 is a hmm an "eastern block" clone of Z80 hehe ...), unlike the TVC here which contains a specialized chip at least (though a common one!) the 6845 CRTC. Though it was already done it seems: http://primo.homeserver.hu/html/epitesutanepites.html

I ask about TVC64 not coincidentally. It is most similar to the Enterprise.
Maybe it would be easier for me to recognize how works the inputs EXTC and EC0-EC3. I'm afraid a little of doing experiments on expensive original EP.
The 6845 CRTC chip is quite easily accessible. It was widely used in many computers (Amstrad/Schneider CPC, early PC graphic cards MDA and CGA).

Yeah, I see, I just mentioned Primo, since it's an interesting stuff, that there is no special IC (AFAIK!) in it, other than Z80, not even something like the CRTC, or custom stuff, like the ULA in Speccy, or Dave/Nick in EP, etc. But surely, I see your point. I think, you can't damage an EP with those inputs too much ... AFAIK, EC0-EC3 and EXTC both of all are inputs, normal logical evel, etc, so you can even build some buffer between them, etc.

In theory, EC0-EC3 are colour inputs which are treated if EXTC is driven active (low active, if I remember correctly). Also, some Nick I/O ports, you can tell how they are should be used. Since I *still* (please do not comment, hehe) don't have a usable EP for real, I can't try, but I already suggested, that somebody should try to drive EXTC active externally and only put a constant "colour" onto EC0-3 (eg, ground all of them, maybe on some resistor though, just to be safe). Then on 0x80 port of Nick, the handling of external colour input should be "set up" for as you like, and you can try, what happens on the screen when you drive EXTC active or inactive, or even setting EC0-EC3. My idea, that it should display that colour. Since it's more or less a constant value on EC0-3, and not sync'ed to the pixel clock, etc, surely it looks all on the screen or so, but it's a good and quite simple start to see, if it works this way at all. That's what I think you should not cause any damage, since they are inputs etc, but hey, I can't be sure for sure sure-sure

Or totally the contrary, a smoth scrolling background and using Nick-Z80 to move the sprites...

I guess, somebody with the needed site admin rights should move the conversation of external colour into its place, somewhere in the :UK section

TVC Spectrum emulator generate the Spectrum screen to the external color input.
Using this method also will be good idea for new Enterprise Spectrum emulator, because no attributom conversion needed.

On Enterprise, I suggest this as first try: put a 4 bit counter to the Nick clock, these 4 bit connected to the EC0-EC3, and lets see what happening when EXTC active.

What I wait: external color input will select one of the 16 colors, instead the current pixel colour (priority can be selected, see the Nick documentation). And I'm 99% sure 16 colors can be used with Hires 2 resolution. See the Text 80, it is use 8 colors in this mode.