7 replies to this topic

[tf_hh]

Hi,

there´s an auction (no. 320897889221) on ebay offering a XEGS with a RGB output. I never see this PCB before, it is possible an old VBXE (1)? If not, have anybody seen this before?

Because auction may ending, here is the picture by the seller:



Regards, Juergen

[Joey Z]

well, first of all, that chip on the daughtercard there is GTIA, and I think VBXE needs ANTIC on the board. also, in the pictures within the auction, it shows a SCART cable end. these cables (I think) DO support RGB, but they also support composite and due to the nature of the Atari's, I doubt that it outputs RGB.

[Rybags]

Entirely possible it's RGB, why else would GTIA need mounting on an external board?

Plus it's a Secam GTIA, it's a whole lot easier to convert to RGB than Pal or NTSC.

[Joey Z]

well, I was under the impression that the FGTIA doesn't output RGB directly, it only outputs SECAM compatible composite video or luma/chroma.

[Rybags]

It doesn't.

Simius might be able to help out.

Auction - eBay Auction -- Item Number: 320897889221

Thread translated from Atari Area Poland:  http://translate.goo...php?id=4938&p=2

[Bryan]

Because SECAM is more complicated to generate than NTSC or PAL, it's possible that the SECAM GTIA outputs video components that are converted to proper SECAM by an external IC. This might make it a better candidate for RGB conversion than a normal GTIA. Just a guess- I haven't looked at a SECAM schematic.

[Rybags]

WIth Secam you have Y (luma) as per normal, and (B-Y) alternating with (R-Y) per scanline.

The FGTIA doc isn't totally clear but it seems some of the generation is external, there are 3 pins which output colour information, so likely this is a digital output which would be easy to convert to RGB either via formula or lookup table with the addon board.

Edited by Rybags, Mon May 7, 2012 9:43 AM.

[candle]

this is as Gary said - secam unit (mind gtia and monitor port - something unheard of in a XEGS) and Simius FGTIA to RGB board for RGB output