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Simius

New development: GTIA in CPLD

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Simius, have you considered designing a STophia ? I mean....a Sophia (like) PCB for the Atari STs Video Shifter ?

 

Id kill for a direct DVI output on my Mega STE ;)

 

I have no clue if this woud be much harder to do ? Maybe it could even provide extra graphics modes (which I _would_ find useful on the ST ;)

Edited by Level42
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It's hard to say. How many Shifters are there? C025914, C070713, C101608, C300588 or more? With some it would be easier, with other harder. An installation would be not as easy and solderless as on the XL/XE, especially on STE (PLCC84 Shifter) For now I don't even have any ST.

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Simius, have you considered designing a STophia ? I mean....a Sophia (like) PCB for the Atari STs Video Shifter ?

 

Id kill for a direct DVI output on my Mega STE ;)

 

I have no clue if this woud be much harder to do ? Maybe it could even provide extra graphics modes (which I _would_ find useful on the ST ;)

 

Looks like someone was attempting this over at the Atari Forums:

http://www.atari-forum.com/viewtopic.php?f=15&t=32445

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topic says: "New development: GTIA in CPLD", but this is just an Atari 8bit computers upgrade for connection to RGB? Am I wrong here? Do you have vhdl code for GTIA replacement?

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topic says: "New development: GTIA in CPLD", but this is just an Atari 8bit computers upgrade for connection to RGB? Am I wrong here? Do you have vhdl code for GTIA replacement?

I think it listens to writes to acquire the bus data and then decodes an0-2. So is doing most of the work of gtia. Rather than just converting lum0-3 and colour to hdmi.

Edited by foft

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topic says: "New development: GTIA in CPLD", but this is just an Atari 8bit computers upgrade for connection to RGB? Am I wrong here? Do you have vhdl code for GTIA replacement?

 

Not completely. There is no P-M collision detection, START/SELECT/OPTION keys, trigger inputs.

Edited by Simius

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OK I'm puzzled. What is the correct pin-out of the DB9 on a RGB Rev. B board ?

 

So I finally wired up a temporary db9 to SCART cable and all I got was some I synced trash on the screen......

 

Looking at what can be wrong.......I finally realised I don’t have a Rev.B board but Rev. a.......

 

LOL

 

Firing up the soldering iron again....

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Hi,

 

Just a little post (as I promised to Simius) to show the result on 2 Atari 5200 consoles (2 and 4 ports).
The Mod is very simple because all 5200 have the GTIA on socket and the result is amazing!

 

Thanks Simius ;)

 

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Well.....I let the thought of soldering my own SCART cable go and ordered a (temporary) sub-9 one from Coolnovilties. I ordered a Rev. A cable as I believe mine to be a Rev. A Sophia, at least it looks like it :)

 

However....I just tried about everything I could and I don't get a picture. I verified with my Atari ST that my B&O MX4000 gives a (brilliant) RGB picture so I'm sure the TV is set-up correctly for RGB input.

 

But all I get is some weird blue stripes. I tried it in two machines. I tried all kind of jumper settings....nothing works......Simius any ideas ?

 

How should the jumpers be set with a CRT RGB TV ? I assume jumper 1 closed (interlaced) and jumper 2 open (RGB). But I also tried all other possible combinations....

Edited by Level42
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This is my Sophia and the resulting picture. I can see something like the cursor at boot up and then something that vaguely resembles READY.

post-25272-0-06205300-1530020934_thumb.jpg

post-25272-0-35291400-1530020947_thumb.jpg

Edited by Level42
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I finally realised I don’t have a Rev.B board but Rev. a.......

 

Wow, and I thought I got the last of the A's when I ordered in November. :) Not sure why A's keep coming since B's are long out, but I really think something in the package indicating Rev. A or B would be a good idea.

 

Anyway, I have the A and incorrectly ordered a B cable. Sound worked and was play but the image was highly distorted, although I could make the "Ready" out (see a pic of my post here).

 

If you have the same symptoms as I did, then you have the B cable. Can you open up the DB9 end and see if it matches mine? I posted a pic several posts back.

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I already have my Sophia quite a long time but never got to install it earlier.

 

I definitely ordered a Rev. a cable and the sticker on the SCART plug says Version 1 or something like that...

Yeah I already thought about checking the pin out through measuring, not sure if opening it up will void warranty ;)

 

I guess simply screwing open the sub D and making a picture won't hurt. ....and there can also be a problem in the SCART connector of course but I hope that the cable is tested before it gets shipped out....

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I guess simply screwing open the sub D and making a picture won't hurt. ....and there can also be a problem in the SCART connector of course but I hope that the cable is tested before it gets shipped out....

 

Unfortunately they can't test it. They don't have an Atari with either Sophia revision to test. Still, the Rev. B they sent me was perfect, as they are outstanding at what they do. I simply re-soldered the pins to Rev. A and it worked.

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Well the reason why I put money in a ready made cable is that I totally hate soldering connectors. I do every solder job but not that...I just hate it.

 

They don't need the original hardware to test the cables they can easily make s simple test board and connect the two connectors and have a bunch of LEDs light up of the connection is correct....but the work looks to be OK....

 

Will measure the cable tonight....

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Right, the blanking signal is simply not connected !!!!!

 

This way the TV will receive no signal and will select the composite input instead of RGB,.......

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Warning.....do NOT buy the current Rev. A coolnovelties sub-d9 Sophia to SCART connector. It is NOT correct.

 

They wired pins 6,7 and 8 of the sub D together and connected this with the brown wire to pin 16 on the SCART connector. Pin 6,7 and 8 are GND as per Sirius drawing. Putting GND to pin 16 on SCART will force the TV to select composite in but we want RGB !!!!!

 

As per SCART spec a voltage of 1-3V needs to be provided to pin 16 to force the TV to RGB input. Im not sure what Sophia puts out, often (like 1088XEL) simply 5V is put out and although out of SCART spec, most TVs seem to survive.....anyway....this is wrong and I'm not sure if I can correct it, I think I will need an extra wire....

Edited by Level42

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Although this isn't exactly what you are looking for, this schematic will at least show you what is needed on SCART end of things to have RGB selected, and an image appear on screen.

 

post-42561-0-64988400-1525198836.png

If you look at the last page of the 1088XEL schematics you can backtrack that to the DB9 connector for a Sophia RevB board (CSYNC is pin 8 on Sohia RevB).

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Thanks Michael, yeah I actually used your schematic as a reference ! :)

 

Well I got It working !

 

I had to correct these faults in the cable as coolnovilties makes it:

- Move the brown wire from pins 6,7 and 8 and solder it to pin 9

- make a short (wire) between pins 6,7 and 8 (these should already be connected to each other) and the metal of the sub9D connector. This is not exactly how it should be according to the "rules" but at least you get a picture.

 

I'm pretty annoyed that I now still had to waste an evening to get this cable to work..... I spent the money to NOT have to solder....let alone do fault finding....

 

But at least I have a picture now....

 

So....until coolnovilties corrects these mistakes I cannot recommend buying their Rev, A cable for Sophia.

 

 

I am also going to say something about the cable they use.

 

There is only a single shielding. The individual wires are NOT shielded which introduces cross talk between the Signals. IMHO this is NOT a suitable cable for SCART. Even the cheapest SCART cables that support RGB have an individual shielding for at least the R,G and B signals.

 

I already feared this because the cable,is so thin.

 

It was also the reason why I wanted a ready made cable, it is a royal pain in the ass to solder all,the individual wires and shield to all the pins on a SCART connector....

 

Anyway....I'm anal with analogue audio and video cables, probably a lot of people won't see it, but you loose a part of Sophia's output quality with a cable,like this....

post-25272-0-56290000-1530138867_thumb.jpg

Edited by Level42
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The good news is that my ANTIC switcher works just fine together with Sophia.

Not that I expected that it wouldn't, but you never know for sure until you see it working :):)

 

Looks like AntiX and Sophia will be best mates inside any A8....

Edited by Level42
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In the early years VGA cables were usually made with only one shield and worked fine. It wasn't until SVGA and longer cables that it started to require individual shielding for the video lines. For the freqs we are talking about for the Atari (Sophia, VBXE, or an ST) a single shield is probably perfectly adequate. As for audio and video sharing the same shield, I've never heard or seen any evidence of cross talk on the systems I have tested. Perhaps if you have Bat ears you might hear the horizontal sweep leaking through ;) .

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I can not stand the whine of flyback transformers on some CRT's and hissy power supplies etc... don't pick on my Canine ears, or echo location bat ears... usually it's because of poor design or failure imminent. I hated poorly shielded monitors, cables, and poorly made televisions back in the day....a real headache... freaking annoying... when I was in the shop or in center... I always knew and could locate the monitor someone left on as they left for the day...

Edited by _The Doctor__
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I can not stand the whine of flyback transformers on some CRT's and hissy power supplies etc... don't pick on my Canine ears, or echo location bat ears... usually it's because of poor design or failure imminent. I hated poorly shielded monitors, cables, and poorly made televisions back in the day....a real headache... freaking annoying... when I was in the shop or in center... I always knew and could locate the monitor someone left on as they left for the day...

 

Usually that's more the case, and normally not something that is heard through the audio system. On the noisier sets it usually pointed to a flyback transformer that had loosened up so to speak and was a physical movement in the laminations or wiring.

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So funny you mention that.....I used to have razor sharp hearing, but that very TV you see on my pics (B&O MX4000) .....whenever I turn it on my son complains about the high-pitched noise.....and I barely.....if at all hear it. One of the less fun things of getting older.... ....

 

 

Michael.... You might be correct....but not entirely....

 

We used to have DIN cables for audio connections in the early 70's. They were convenient because just one plug. (Exactly the same one as the video port on the A8's). Especially with cassette- and reel to reel recorders because the RCA connectors that became popular later needed 4 plugs on each side....

 

However, the RCA cables won, because each wire is shielded individually. Audio signals are WAY lower frequency than 15Khz RGB video signals...but still the wires running in parallel over some meters without any shielding......and a SCART cable has many more signals...

 

I'll take a picture of the SCART cable that I used to use when the high-end home cinema consisted of a 16:9 CRT with SCART DVD player. That cable cost me an arm and a leg, but it was worth every cent. Yes I could clearly see the difference. Now, of course there is sense and nonsense when it comes to cables and it all depends on application and viewers' (or listener's) demands. Some people are happy with RF picture.....

Analogue signals are influenced quite a bit by cables. With digital stuff, a decent "regular"HDMI cable is good enough, because a 1 is a 1 and a 0 is a 0....

 

On the other end.....with SCART the main problem was that signals were often bi-directional and this influenced picture quietly. I actually cut off some wires that I didn't need with the old home cinema set-up to prevent cross-talk. (and you bet it worked).
Now, of course, there are no signals traveling back from the TV to the computer in this situation so the whole cross-talk thing might be not so relevant. All in all, it's a detail issue anyway, the last 5% or so....

 

And this cable is temp only anyway....until I finally have some time to install Jon's 13 pin DIN connector idea.... :D I bought that cable from coolnovelties too....let's hope it's better :D

Edited by Level42

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And this cable is temp only anyway....until I finally have some time to install Jon's 13 pin DIN connector idea.... :D I bought that cable from coolnovelties too....let's hope it's better :D

 

Jon and I have had good success with the Version 2 1088XEL specific cable by Cool Novelties, and that has two (stereo), not just one audio channels being sent down the line. later today I'll hook everything back up and crank the volume up to 11 (not just 10 ;) ) and see if I can hear any of the video related stuff bleeding over to the audio lines.

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Yeah I got that cable here too. The Sub9D is only temporary for me, I try to keep the externals of my A8's as original as possible so I'm not going to use it....

 

So I figured I'd go with Jon's idea of using the 13 pin DIN socket....there is still one issue with that.....you still have to enlarge the former RF out hole......and there might be a way that this is not necessary.....

Edited by Level42

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