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Plantronics ColorPlus

S

Scali

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I have two machines which are Plantronics ColorPlus-compatible.
One is the onboard video on my Commodore PC20-III. The other is a Philips P3105 which came with an ATi Small Wonder.
(By the looks of it, the onboard video of the PC20-III is just an ATi Small Wonder copy-pasted onto the mainboard... but Commodore does not mention ATi anywhere).

Anyway, there is not a lot of information on programming the extra modes.
I have found this manual for the PC20-III: http://dostalgie.de/downloads/pc10III-20III/PC10III_OM_COMMODORE_EN_DE.pdf
It contains a dump of the CRTC registers, and info on how the pixels are made up.
This sounds to me like the 16-colour mode is technically always on (it does not seem to mention any extra control register to enable/disable it... I will have to take a closer look at the CRTC register dump, but it says it's the same as CGA, which it probably is). So just writing pixel data to the second plane should 'blend' with the regular CGA plane to enable extra colours.
I will have to experiment with that.

The only other information I have been able to find so far is this: http://www.seasip.info/VintagePC/cga.html
It mentions an extra control register at 03DDh, which apparently controls how the two planes work together.
The same register is also described here: http://www.seasip.info/AmstradXT/1640tech/section1.html#1.11.3.3
Aside from that, I have found some programming example on the ATi Small Wonder disk, which I have yet to study closer, but that may be specific to the ATi card, rather than generic Plantronics-code.

So, does anyone have any experience programming Plantronics ColorPlus and/or has some extra documentation on it?
 
FishFinger said:
The http://www.seasip.info/VintagePC/cga.html page says that bits 4-6 of 3DDh control the extra modes, and that if bits 4 and 5 are both 0 then it operates as normal CGA.
Click to expand...

Yup, but it would be a huge omission by the Commodore manual if you need to set this register yourself before the extra modes would work.
So... I wonder what its default value will be after the CRTC is reprogrammed with their values.
 
I now have a real IBM CGA card as well... and interestingly enough, the colours from the NTSC output are completely different than on the other two machines.
Does anyone know more about this? I heard that Tandy/PCjr also output different colours than CGA... a phase shift in the NTSC signal, which I think this is as well. I just wonder if it's the same phase shift, or if it's just completely wrong and incompatible.
This is only with the artifact colours when you enable colorburst by the way. In text mode and 4-colour graphics modes, the colours are correct. The Plantronics 16-colour modes also seem to work the same way, and seem to be correct as well.
 
Getting back to the trusty old Paradise PVC4... Does anyone happen to have a disk with utilities for this chip or something? It probably shipped with that originally.
 
Did you ever make progress with this? I really want to see the 640x200x4 mode in action - I know not the most exciting and can get it from a Tandy, but I have a PVC4 motherboard on the desk right now and it is what is interesting me.
 
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