New Hardware: Atari 400/800 Super Color CPU Card

[_The Doctor__]

in order to fix the artifact, the pot need to be able to advance through a color clock and/or retard through a color clock... the artifacts are base on a half color clock so you need full swing to dial it in, use of a capacitor has been use to firm/alter artifacts on NTSC and XE's and XL's but looking at SCCC it looks like the only way to do it is with his delay pot. Just some food for though. I didn't dig further, and I'm sure folks with slide rules and mega cool degrees working with  $$$ equipment would have something to say anyway. I am just giving a where to look, and possible what to do... pointer in the direction of the problem.

[Krenath]

It looks like, while I can adjust the delay pot by what looks like it should be more than enough, it's entirely in the opposite direction from what I want. 

The current artifact colors are purple (magenta) and green.  (Black line in this stolen color wheel image)
About 60 degrees around a typical RGB color wheel are the red/cyan colors I can get with the delay pot.  (gray line in the color wheel)

I'd really like to go about 15 degrees back the other direction around the color wheel to something around yellow-green to blue-violet and I think that would look about as accurate as I would want. (toward the white line) 

That, or I need about 315 degrees more delay rather than 15 degrees less

Edited February 19, 2021 by Krenath

[_The Doctor__]

[Krenath]

Don't get me wrong; I'm not complaining about the Super Color CPU card.  It's still great!  I'm not planning on changing back.
It's just that it's so close to perfect that I *wish* I could get the last tiny little detail ironed out.  

Meanwhile, here are a pile of images that show what I see on my old CPU card as compared to the new Super Color CPU Card:

 

Original CPU Card, Composite Video, UAV.XEX color test and Exodus: Ultima III

 

Original CPU Card. SVideo: 

You can see hints of the artifact colors even in svideo on the original CPU card.

SCCC Card, Svideo.  You can see that Ultima is entirely monochrome since it got all its color from artifacts.

Very tiny hints of artifact colors, but not the same as above.
 

SCCC Card, Composite, UAV.XEX color test and Exodus Ultima III

You can see that we've gone from green/blue  artifacts to purple/green.  You can also see that the colors for Ultima are way off.

 

Here's what happens if we adjust the delay pot as far as it goes:

Well.  The cyan color is closer to the original blue than the purple was.  But the red is as far off as it can get from the original green.
(The color inversion jumper was on for the UAV color test photo, by the way)

Time to put the Color inversion jumper on:

Close.  Probably good enough for most purposes.  Ultima is closer, but very purple-heavy. 

This is how I'll be using the SCCC card from now on.  Unless I find a way to tweak the artifact colors closer to original.

 

Testing CPU cards.  

 

Made use of a pin header so I could have a quick disconnect for Incognito instead of soldered leads.  The SCCC board had  holes for this purpose. 
If you're inventive, the original NTSC CPU board does too:  These two pads don't connect to anything else on the board but unpopulated pads I can run jumper wires to.
This lets me quickly swap CPU cards and connect them to the Incognito.

 

 

Edited February 19, 2021 by Krenath

[_The Doctor__]

UAV for the win again.

[leech]

@Krenath
DId pressing Control-X a bunch as it loads give you a color selection screen?

[Krenath]

2 minutes ago, leech said:

@Krenath
Did pressing Control-X a bunch as it loads give you a color selection screen?

No part of the intro screen or menu screen seemed to respond to Control-X.

[Faicuai]

4 hours ago, Krenath said:

It looks like, while I can adjust the delay pot by what looks like it should be more than enough, it's entirely in the opposite direction from what I want. 

The current artifact colors are purple (magenta) and green.  (Black line in this stolen color wheel image)
About 60 degrees around a typical RGB color wheel are the red/cyan colors I can get with the delay pot.  (gray line in the color wheel)

I'd really like to go about 15 degrees back the other direction around the color wheel to something around yellow-green to blue-violet and I think that would look about as accurate as I would want. (toward the white line) 

That, or I need about 315 degrees more delay rather than 15 degrees less

 

The key point here is to establish a sound or proven reference of what Artifacts colors should be. To this extent, the most notable reference is FLIGHT SIMULATOR II.

 

The artificial horizon is BLUE on the top, and ORANGE on the bottom. Depending on your flight. sim version (disk or cart), these may appear vertically transposed, but those are the right colors. How do we know? a) it was the author's original intent, b) most importantly, because that is how official aviation instrumentation looks like, in REAL life. 

 

If your baseline artifacts reproduction in TODAY's modern NTSC color decode is Green/Blue, that would be a good start, and it would most likely imply that you are decoding hue-band $01 as light parrot-green instead of gold-yellow (as it should perceptually be). In this case, all you would need to do is RETARD color-phase (hue) on your CRT or video-processor until hue $01 is gold-yellow, AND only then adjust hue-band $0A (Star-Raiders shields) with COLOR POT so it looks dark grayish-blue. Artifacts should now look Orangish + Blue, instead of Green + Blue. Any perceptual errors would now be shifted to band $0F, where it should end one step behind band $01, so you effectively get 256 colors (and not 240, as most adjustments out-there erroneously end).

 

You can use Altirra's Additons .ATR "colormap" utility for all of the above. There is simply no substitute for it.

 

Edited February 20, 2021 by Faicuai

[leech]

1 hour ago, Krenath said:

No part of the intro screen or menu screen seemed to respond to Control-X.

Ah, sad.  Seems to only be for Ultima IV.

[Krenath]

49 minutes ago, Faicuai said:

How do we know? a) it was the author's original intent, 

 

Then again, in the Ultima III game, we also know it was the author's intent that water should be blue and trees should be green.  Much as they are in real life...

Colormap does definitely help make sure that the color pot is adjusted right, since one can see when band $01 almost matches up with band $0F.  That's quite nice.  

But only the color pot affects on the color bands on the right.  Delay settings don't appear to affect real colors on the right side of the screen in any way.

Adjusting the Delay pot changes the artifacts on the left side of the Colormap screen (which is what I'm trying to affect) from green/purple to cyan/red and no further. 

I cannot get the orange color you speak of using artifacts even if I wanted to.  (And it's definitely the opposite direction of what I'm wanting)

 

SCCC output, with color invertor jumper.

While close, the bars on the left side should be shades of blue.
 

With inverter jumper removed:

 

SCCC output in SVideo mode

 

And here's the output with the inverter jumper in place and the delay pot set to the extreme right:

 

Nowhere in the color range can I set the artifact colors to the correct blue/green nor any version of blue/orange.

 

Below is Colormap run on the original hardware CPU card with the correct artifact colors (at least, correct for NTSC GTIA) :

 

And here's the same thing in SVideo mode, not that it tells me that much:

 

Edited February 20, 2021 by Krenath

[_The Doctor__]

There is no one size fits all on this one guys... some of the programs only let you set the artifact color once at initial run.

It seems also that some people are unaware or forget that artifact color changed during production, as one chip artifacted + a half color clock or the - a half color clock... and the supporting circuitry also affected this....

that is why some programs ask you what you see and you answer, then it sets the correct profile...

as usual I don't give you the engineering manual on it, just the gist of it. You can of course refer back to all that and also scour the forums for it.

 

add to this the different colorspace of LCD monitors and modern day tv sets and you'll have a cumulative issue. You sometimes have to dig deep in a modern tv to find the settings to handle some of it.

Edited February 20, 2021 by _The Doctor__

[Krenath]

22 minutes ago, _The Doctor__ said:

It seems also that some people are unaware or forget that artifact color changed during production, as one chip artifacted + a half color clock or the - a half color clock... and the supporting circuitry also affected this....

I'm using the exact same Antic, GTIA, and CPU chips in all the screenshots above, moved from the original board to the SCCC card.  While earlier or later chips could explain the color difference, this isn't a different chip.  It's the exact same single unit.  So it is indeed the supporting hardware, in this case the SCCC, that is causing the artifact color differences.  What I'm looking for is some way to gain further adjustment range to get back to the original artifact colors for that chip, which so much of my software assumes will be blue for even pixels and green for odd pixels.

Edited February 20, 2021 by Krenath

[_The Doctor__]

yep the part about supporting circuitry ALSO affected this is at play...since sccc relies on internal uav (if you look at it) as part of it's build the inversion jumper is there... but you might try adjusting the delay the other way... it's overshooting one then the other in this case?

 

is there a color space adjust on you television? sometimes called native color or some other ....

 

Edited February 20, 2021 by _The Doctor__

[Krenath]

4 minutes ago, _The Doctor__ said:

since sccc relies on uav as part of it's build the inversion jumper while not there might be able to be resurrected... 

SCCC has an inversion jumper.  This seems to only swap the artifact colors.  Even pixels' color becomes odd and odds' color becomes even.  It doesn't appear to allow adjustment of the clock in the other direction. And doesn't affect normal colors at all (aside from subtly shifting their position onscreen).

[_The Doctor__]

so what did you see with delay to extreme left?

 

give me enough time to make and correct a post before jumping on it... I do have to check some of what I am typing... for instance I am going to check what samsung calls their color space in just a minute...

Edited February 20, 2021 by _The Doctor__

[Krenath]

32 minutes ago, _The Doctor__ said:

so what did you see with delay to extreme left?

With the delay to the extreme left and the invert color jumper in place, I see purple artifacts for even pixels and green artifacts for odd pixels. 
This is the closest to the original blue and green artifacts as I can get.

 

Original colors on original CPU card, and the target colors I'm trying to adjust for:

With the delay to the extreme right, the artifacts are now more red and cyan.
I have a lot of adjustment in this direction to get to these colors. 
But I really would prefer to adjust the other direction, further than the pot can turn.

 

Removing the invert color jumper simply swaps the artifact colors with no other effect.
Below is with the pot turned far left and the invert color jumper removed.  



If I now turn the delay pot to the far right, I once again get the red and cyan colors, only swapped even with odd.

 

 

Edited February 20, 2021 by Krenath

[_The Doctor__]

good so you are closer

your monitor / tv has prolly

color tone- cool, normal, warm, warmer

adjust til closer but not messing up normal colors

it also should have standard mode etc. that will unlock color space

it should give native / auto / and some other choice

try those... native usually give a wider color space

and auto fudges it a little...

there is a flesh tone setting

continuing down is individual colors r g b.... and tint control

 

utilizing these you should be able to dial things in.

 

The SCCC is not calibrated to NTSC properly so it would seem adjusting like this all we can do atm... being based on the uav this is odd indeed...

 

Edited February 20, 2021 by _The Doctor__

[Krenath]

Ideally, I'd like to leave the monitor settings alone.  This monitor is also used as part of my three-monitor desktop setup.

It's currently in "Normal" settings mode, and any adjustment to try to affect the artifact colors will likely just mess with all the normal colors as also.

Personally, I'd rather look for something like an SMD resistor I can replace with a higher or lower value to adjust the effective range of the delay pot.  
It appears there's a 47 ohm resistor near the delay pot with a trace heading for it.  It might be that a larger or smaller resistor there would nudge the delay in the direction I want.

[_The Doctor__]

it may be possible changing that resistor but I also think if that fails a capacitor might be involved as well..

 

I edited as I went so some quotes will be wrong and might need re quoting or edits

 

You still are much closer so that's a good thing... it's a tough thing to have multiple items on a televisions that doesn't do presets for each input like some of the displays of old.

Edited February 20, 2021 by _The Doctor__

[Krenath]

And also part of the reason I'd like to leave the monitor settings alone is I want the color settings to be *right* for this machine.  

The same machine on the same monitor using the same CPU, GTIA and Antic chips gets the same (though blurrier. of course) normal colors, but gets different artifact colors when I change out only the supporting circuitry.

I would personally prefer to have everything about the color settings as close to identical as I can so I don't have to trade away artifact color accuracy to get clear video.

[_The Doctor__]

the color space on modern displays are not correct so it can be a tall order... that is why Faicai uses a processor (a very nice but expensive one) to adjust all the parameters.

 

Fixing the sccc for NTSC could be very simple, but more than likely you will need to be referencing an oscilloscope to show what it should be versus what it is and consulting with the creator of the card... as he'd be able to calculate the difference and give you a better fit versus trial and error thus reducing the amount of rework needed.

Edited February 20, 2021 by _The Doctor__

[Krenath]

If the original hardware were showing the same purple and green artifact colors, I'd be willing to blame the monitor and its NTSC color space.  But I keep going back to the fact that without changing anything else, swapping the CPU card between the original and the SCCC results in the artifact colors changing significantly.  

Which is why I'm perfectly willing to try adjusting the value of whichever components would give me the equivalent of more adjustment travel to the left.  

[Faicuai]

2 hours ago, Krenath said:

Colormap does definitely help make sure that the color pot is adjusted right, since one can see when band $01 almost matches up with band $0F.  That's quite nice.  

But only the color pot affects on the color bands on the right.  Delay settings don't appear to affect real colors on the right side of the screen in any way.

Band $01 and Band $0F should NEVER match. Otherwise, you end up with a 240  color computer, and we lknow ours outputs 256 (!) Should look more like this:

 

Your Screen Phase (hue) will affect color-band $01 and just a few below it (ion the right side of the screen). It will also affect the artifacts RIGHT column.

 

The problem is that your main artifact phase seems off (this is where you need artifact's phase control on your video upgrade). It should be BLUE on the left-side and GREEN on the right side. Once you adjust SCREEN's PHASE (hue), the RIGHT artifact column should turn orangish, and you should end with the original artifacts that enable correct display of Flight Simulator. For playing Ultima, ADVANCE screen's phase back to ZERO.

 

Also, check this out (look at FS2 and Ultima, and how much nicer they look):

 

 

And here is how FS2 should look like, compared to my own actual flights / cockpit recollections:

 

 

Edited February 20, 2021 by Faicuai

[Krenath]

Just now, Faicuai said:

Band $01 and Band $0F should NEVER match. Otherwise, you end up with a 240  color computer, and we lknow ours outputs 256 (!)

 

Your Screen Phase (hue) will affect color-band $01 and just a few below it (ion the right side of the screen). It will also affect the artifacts RIGHT column.

 

The problem is that your main artifact phase seems off (this is where you need artifact's phase control on your video upgrade). It should be BLUE on the left-side and GREEN on the right side. Once you adjust SCREEN's PHASE (hue), the RIGHT artifact column should turn orangish, and you should end with the original artifacts that enable correct display of Flight Simulator. For playing Ultima, ADVANCE screen's phase back to ZERO.

 

 

I misspoke.  by stating that band 1 "matched up" with band F, I meant that band 1 was one step different from band F, making a smooth color transition from one color to the other.  

What is this "artifact's phase control'?   Does that refer to the color pot?  No matter how I adjust the color pot, band 1 seems to stay approximately the same color, a light orangish color.  I adjust the color pot until band F seems to smoothly transition into band 1 just like all the rest of the colors do.  

No matter how I adjust either the color pot or the delay pot, it is impossible for me to get blue as an artifact color on this SCCC card.  I can have PURPLE and GREEN or I can have RED and CYAN.  There isn't enough adjustment range to get any other artifact colors.

 

[Krenath]

Here's pictures from subLogic's Flight Simulator II, if that'll help, since we keep referring to it as the benchmark for artifact colors:

ALL of these pictures were taken with the same monitor, same computer, same CPU, same GTIA chip, same ANTIC chip.  The only thing switched out is the Atari CPU card for the SCCC card.

 

Here on the SCCC card, the sky is dark purple and the ground is dark green.   

The artificial horizon is green on top and purple below.  There is no orange.

 

Here's with the original Atari CPU card and the same chips:  
The sky is still purple and the ground is dark green. 
(The upper half of the screen appears to be a four-color mode and not Graphics Mode 8.  Adjusting the delay pot or color invert jumper does not affect colors here.  Switching to SVideo mode confirmed this, as the top half of the screen remained in color and the bottom half went entirely monochrome.)
On the artificial horizon, the top is green and the bottom is blue rather than purple.  There is no orange.



I tried to find Microsoft's Flight Simulator for Atari but I could only find PC versions, not Atari versions. 
Those are pictured with a blue and orange artificial horizon on the PC version, yes, but I don't think the Microsoft version was ever an actual product for Atari.

If I put the SCCC back in the computer and adjust the delay pot all the way to the right, here's what I see:

With the color invert jumper:
The sky and ground colors are still the same,
The artificial horizon ball is cyan on top and red on the bottom. 
There is no true blue or orange in the bottom half of the screen.

 

Without the color invert jumper:

The sky and ground colors remain the same.
The artificial horizon ball is red on top and cyan on the bottom. 
There is no true blue or orange in the bottom half of the screen.

 

No matter what settings I try with the SCCC card, I can not get artifact colors that match the original Atari CPU card, NOR can I get the colors that Faicuai says I should see.  
The closest I can get is reddish-purple and green or cyan and red.  
On the original hardware, there's no orange at all and no way to adjust it so there would be.


Edit:  I've also tested with a second GTIA and ANTIC chip from a second Atari 800 and I get the same results.
Edit2:  The second Atari 800, which is unmodified, displays blue and green as its artifact colors.  There is no orange.


 

Edited February 20, 2021 by Krenath