So I have an AppleColor 100 RGB/80 Col card for my A2E but I (sadness) no longer have the monitor that went with it. I've seen them up for sale for big $$$ in the past (in fact, there's one on eBay available right now for 700$, which is a little bit more than what I'm willing to spend at the moment, although I am severely tempted).
What I'm curious about is if anyone out there has come up with any sort of other alternatives for a monitor to use with that RGB card. I've read about people modifying the card in order to use the Apple 2 GS color monitor, but I'm not sure I really want to take that step yet... has anyone made/purchased some sort of converter that goes from that RGB card to either VGA or HDMI?
The Apple IIe AppleColor 64k 80 Column RGB card output is digital RGBI at 15.7 kHz, the same format as IBM CGA graphics. Sync is done differently, however: IBM CGA uses (+) positive horizontal and vertical sync; while the AppleColor card uses (-) negative composite sync.
The card's pinout is given in the Apple II FAQ:
This can be converted into the sync format expected by a CGA monitor using two chips and a few other components. Here is one design: http://knut.one/A2E-CGA.htm
The recent CGA-to-VGA converters like the MCE2VGA may be adaptable to the AppleColor RGB signal. I haven't looked to see if they can handle (-) composite sync but it is possible.
Didn't the 8-Bit Guy (youtube channel) do an RGB hack on a CRT television that had on-screen menus?
I wonder if that would work...
I found the link here:
https://www.youtube.com/watch?v=DLz6pgvsZ_I
but I am not sure if the level of the signals from the CGA like Apple Card are usable for a TV as input.
Is that RGBI ??? Like the Commodore 128 with TTL - Levels ?
Then a RGB mod of a TV will definitly not work.
You may look for a RGBI to SCART adapter or search for a Commodore 1084s monitor.
The 1084s has a RGBI input. I am absolutely sure that, there are a lot of RGBI to RGB things out there. Most of those are for the Commodore 128 but if the signal levels and timing is the same as CGA ... I do not see a problem.
Most adaptors consist of some logik chips to combine the sync and colour signals that, then get feed in a resistor network for converting the TTL to analog.
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So colors 8-15 (well, except for 15 - and it's hard to tell with 8 but it is different) are coming through differently but the palette doesn't really match at all.Color 5 should be gray instead of yellow, for example. What is interesting is the border: the right side should be yellow, but appears to come through as the gray that it was meant to be... more experimenting to come.
You got me thinking about how I would approach this. As I use a lot (And I mean a LOT) of different retro systems, I have got quite comfortable with how to upscale everything to "modern" displays.
To that end I have both a 15KHz monitor and a couple of GBS Control boxes. (GitHub - ramapcsx2/gbs-control)
There's also a nice little project designed to convert CGA to "VGA" (The quotes are there because it needs the destination to be able to cope with the sync speed. Eg 15KHz for a lot of things) designed by Necroware. (GitHub - necroware/mce-adapter: RGBS converter for MDA, Hercules, CGA and EGA)
Now we still have the problem of the inverted CSync, but I suspect a 7404 (Probabaly a HCT) would take care of that difficuly. If you were dedicated enough, you could probably even modify the equation in the Necroware adapter directly.
The approximate signal pipeline would be Apple IIe -> Sync Inverter -> Necroware MCE adapter -> GBS Control -> Modern Display.
I don't have the card to test, I'm afraid. Just pretty much everything else.
Hope you get a good solution!
Chesh
...really, I think the main thing missing from my setup now is getting the colors right.
This post old post from comp.sys.apple2 (https://groups.google.com/g/comp.sys.apple2/c/qWR-vM4SXh0) talks about the notion of the AppleColor 100 having some special circuitry to do something with the signal to make the "Apple" colors. There's a mention of the schematic being available but I haven't found it yet.
You may have run into the situation that was discovered in this thread:
Digital RGBI produces 16 colors, with the "top 8" of them being "intensified" or lightened versions of the "bottom 8". IBM CGA is a slight variation on this which adjusts "dark yellow" to be brown.
But the colors on the AppleColor 100 appear to be a different set of 16, with no correspondence between an "upper and lower 8", in other words, it is just four digital wires into an arbitrary color decoder instead of RGBI. Making this type of decoder from resistors may not be possible. It would be possible using a 4-to-12 bit lookup table as mentioned in the comp.sys.apple2 thread.
There is also a "Technical Procedures" document linked in the above thread.
...over on the apple2 subreddit someone referred me to this (https://jcm-1.com/product/universal-video-adapter-for-apple3/) product which looks like it might be what I'm looking for. He's got a YouTube video on it which I watched - I think I'd be able to use the signal that's the "non-CGA" signal with my VGA converter... the website has a picture with his converter in line with a Gonbes - which isn't what I have - but I'm assuming that I would go down that route. (It looks like his TTL output is just the CGA colors swapped around which isn't really what I want.)That being said, I noticed that color 1 (Red/Magenta) in the Gonbes picture (and on his Apple monitor in the video) looks more purple than the magenta in the first picture in the thread that Robespierre referrenced. That picture in that thread is how I remember that color looking on my AC100 monitor. Joe says that that part of his converter was copied from some Apple /// product manual - I'm poking around to see if I can find it (anybody know which one?) - and so those colors are the colors meant to be displayed on the ///. I'm thinking about buying one of those converters, but I'm also thinking about trying to duplicate whatever A3 circuit he did but perhaps try to modify it to get the colors I remember (like in the other thread).
...in Figure B-2 of the A3+ Owner's manual. Huh. That's a doozy. But nothing really crazy, either... I'm guessing different values for certain resistors...
Circuit built, here's the results...
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...I'm really pleased with how this turned out.
That looks great! I'm so happy this problem has been solved and reported for posterity.
By the way, DougJoe uploaded very high resolution (4624 x 2604) screen images, but the only way to see them in full glory is through the Media Browser.
Sorry about the giant pics, I guess I shouldn't have uploaded them straight from my phone... :/
One other interesting thing to note (that I had to tweak after I first built the circuit) is that the signal from the card ends up being, in a sense, a "RBGI" signal (as opposed to "RGBI"). The Red pin (5) gets mapped to XRGB1 in the circuit, the blue pin (9) to XRGB2, the green pin (2) to XRGB3, and the intensity pin (10) to XRGB4. I ended up having to switch my green and blue inputs. It kind of makes sense as "red" is Apple lores color 1, "blue" is Apple lores color 2, and "green" is Apple lores color 4.
My colors don't exactly match the ones in the picture in the other post (the other magenta still looks more red, the dark green is more green, brown is a little darker) but that could be variations in cameras, etc - it's hard to tell. I did find this (https://sites.google.com/site/drjohnbmatthews/apple2/lores) which purports to give the "true" color definitions.
I will probably either proto/perfboard this circuit or make an actual PCB (just because it takes up so much space behind the 2e).
My original Prince of Persia disk doesn't boot anymore but I really want to see that DHR startup screen so I'll have to get a .dsk and ADTPro it.
I haven't tried PoP yet, but I spun up Dragon Wars, Neuromancer, and Wings of Fury tonight. On my new setup, all three title screens displayed DHR monochrome. Dragon Wars shifted to DHR color after I went past the title screen, I didn't try past the title with Neuromancer, and of course WoF uses regular HGR during gameplay.
My memory is telling me that the title screen of Dragon Wars was in color back on my old AppleColor 100 monitor, but I can't remember for sure. Is there anyone out there that has the AC100 card for the //e, monitor, and Dragon Wars and can check?
I tested the same three screens with AppleWin (1.30.15) in RGB Card/Monitor mode and had the following results:
Dragon Wars: Title monochrome, game monochrome
Neuromancer: Title color, game color
WoF: Title color
...what I've found (at least with the disk images I have from asimov) is the following:
In the same version of AppleWin as above, Dragon Wars tries to use the "mixed" mode of the RGB card to display the title screen... but looking at the video memory, it looks like none of the bytes have the most significant bit set... and when I flip that bit, the colors show. So I'm not really sure about that one - I may try to make a disk image of my dragon wars disk with good old ATDPro and see if it behaves any differently.
The Prince of Persia source code on GitHub appears to be going through the steps documented in the AC100 card manual for the card to show the 140x192x16 mode.
Neuromancer and WoF seem to be making a single read/write to AN3 ($C05E) to switch to DHR (which, outside of the AC100 card, is all that is required). I can't help but wonder (and I'll have to read the other thread here and the Video7 patent very carefully) if there was something in the AC100 monitor that somehow converted/displayed the signal as a composite-style signal so the artifact colors would show up instead of the monochrome in the case where none of the official modes of the card had been enabled?
Why not use a Commodore Monitor at least here in Europe they are absolutley easy to get.
The Commodore 1901 should be optimal as it was build to support analog 40 column composite and svideo and also analog or digital (switchable) RGBI.There are many variants of the Commodore 1084 some have TTL RGBI some not some have analog SCART RGB some not, it depends also if it was sold in an NTSC or PAL country.
Some of the Commodore monitors have a switch to switch between composite and S-Video what is called color kill siwth in the Apple world as far as I know.
No, those are not the same thing.
No Apple II has separate luma and chroma output, because they are not generated as separate signals to begin with. The Apple method of video generation is purely composite: a stream of 1-bit "pixels" which happen to be at the exact frequency of the NTSC color subcarrier. The resulting composite video "edges" get decoded as chroma information by an NTSC monitor, with the color represented depending on the phase between the video bits and the colorburst (a color subcarrier pulse that is inside the horizontal blanking interval). This is why Apple II video always has color fringes around text when graphics are being displayed on screen.
The only way to prevent the color fringes in "Apple world" is to suppress the colorburst completely, which is what the "color killer" circuit does whenever the TEXT soft switch is active. So that means that there is no way to display black and white graphics on a color monitor—unless the monitor itself has a monochrome switch, and the Apple Color Composite monitors all have that. All the switch does is shut off the NTSC color decoder circuit in the monitor; so all video is shown in monochrome.
This difference is also why there was never an S-Video monitor in "Apple world".
Well, to be exact, the frequency of the stream of 1-bit "pixels" is not the exact frequency of the NTSC color subcarrier, but rather an exact integer multiple of it. In the case of NTSC, the color subcarrier frequency is 3.57954 MHz and when we multiply it by 4 we get 14.31818 MHz, which is the crystal's frequency and the highest pixel sampling frequency the Apple IIe is capable of.
So it's same thing as the color part is filtered and needs to be feed in the chroma entrance to still get color.