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Re: Help w/ NEC Multisync 3d and TTL
Scott Alfter wrote:
The service manual lists the following signals as being valid when in TTL
(EGA/CGA) mode:
RA GND
r
R
g
V.D
H.D
G
B
b
So, what is that trying to convey? The V and H sync are somewhat obvious, as
are R,G,B. So, what are the lowercase r,g,b? Inverted polarity? Different
levels?
r, g, and b would be the low bit for each component in EGA mode. g should
serve double duty as the intensity signal for CGA mode.
Yes! Thanks largely to Mike Mahon's kind review of the schematic, I have
things working on the first victim - err, computer. The intensity function
does seem to be multiplexed on the 'g' pin. Last evening, I built an adapter
that lets me view the RGBI output from the 9-pin connector on my C128 :-).
This evening I'll drag out a Mac adapter and see if it cooperates with the IIGS.
I think some of the front-panel switches on the monitor might also need to
be flipped to enable EGA or CGA usage. Since I've only used mine for VGA
and analog RGB, I can't confirm this directly.
I believe that's correct for EGA specifically.
For prosperity, here is the wiring scheme that I'm using:
DB9M HD15F Signal
1 1 GND
2 2 r
3 3 R
4 13 G
5 14 B
6 5 g / Intensity
7 15 b / Mono
8 12 H Sync (and, I believe H/V composite)
9 10 V Sync
For the C128, the secondary r and b are probably superfluous. On a GS, ditto
for V sync.
This is a handy monitor to have around. Wish there was a contemporary unit
available with the same versatility!
Steve