Philips G7000

From: Matt Pritchard <MPritchard_at_Ensemble-Studios.com>
Date: Fri Aug 15 15:40:29 1997

> > the service manual) that the other 2 were luminance (Y) and
> (PAL-encoded)
> > chrominance, or possibly composite colour video and audio if it
> feeds audio
> > through to the TV.
>
> The composite video on the G7400 is Pal encoded, and I'm pretty sure
> it is on the G7000. I have 2 sets of schematics. One for the
> Odyssey2 (where every part number is an internal Magnavox number :-P
> and the other for the G7000) - I seem to recall something about PAL
> conversion on the RF modulator board. I probably just don't remember
> right.
>
> If one is not composite video, where is the sync encoded? On Y (i.e.
> making it composite mono)? I suppose this could just possibly be
> video
> + composite sync - just what I need.
>
> > >> >> What chips _other than the 8048_ are in this device? Is the
> video side
> > >> >> custom or does it use one of the many Philips video chipsets?
> (Philips
> > >> >> Prestel terminals tend to be stuffed with their Teletext IC's,
> for
> > >> >> example...)
> >
> > >Pretty boring, I'm afraid - 8245 and 6110 plus about 20 TTL chips.
> I
> >
> > What the heck are those?
>
> 8245 is a Nat Semi keyboard controller. This chip says Intel on it,
> but
> I was assuming, probably very rashly, that it was the same thing.
>
> [Matt Pritchard]
> We've been unable to find any info on the video chip; though it
> supposed to be an Intel chip. Most of it has been reversed enginnered
> though.
>
> 8 colors
> 4 sprites, 8 by 8 pixels, independantly positioned & colord. can be
> double sized
> 12 characters, independantly positioned & colored, up to an 8 byte
> tall strip from the character rom (512 bytes, 64 chars) can show just
> part of a character.
> 4 quad characters. 4 characters positioned in a horizontal row with
> one character spacing inbetween. independantly colored. Put two of
> these together to make 8 consecutive text characters.
>
> Background grid 10 by 8 blocks with 4 thin line segements around each
> block. Complete off/on control of ever segment. Set a flag in the
> video chip to fill in the large box to the right of each vertical line
> segment.
>
> The horizontal retrace is run into the 8048 so you can count scanlines
> - that is how colors are changed midway down the screen.
>
> 6110 is a typo for 6810 :-), in fact Motorola MCM6810, a RAM chip.
> Looking it up last night I discovered that it is in fact 128 by 8
> (yes,
> 128 bytes!) so I cannot think what it is used for! (It is too slow to
>
> be a video output buffer)
>
> [Matt Pritchard]
> Are you sure it's not 256 bytes?
>
> Philip.
Received on Fri Aug 15 1997 - 15:40:29 BST