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Bruce Abbott

[AQUARIUS] RGB interface with pixel correction

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Not being satisfied with the composite video output, I bread-boarded a circuit using an AD724 RGB to NTSC/PAL Encoder. The results so far are quite encouraging - no streaking or noise, and of course no pixel distortion because the signal is going through the RGB GAL. The encoder circuit draws about 35mA, about the same as the THS7314 video buffer.

 

For this test I used an external 14.318MHz oscillator, which introduced some shimmer due to not being phase locked to the Aquarius. Next I will try using the Aquarius internal 3.57MHz clock. The AD724 can also output S-video, which should produce an even better picture on TVs which have S-video input.

 

Though the AD724 encoder could be added to my RGB board it might be better as an external add-on, then it could be used with other devices. This could have its own oscillator (perhaps with both NTSC and PAL crystals) or use the Aquarius 3.57MHz clock (NTSC only) fed through the RGB connector.

 

Now that I know how good composite video can be, I will also investigate further to see whether the streaking and noise on the stock Aquarius composite signal can be reduced.

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post-40459-0-31021800-1506286632.jpg

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Not being satisfied with the composite video output, I bread-boarded a circuit using an AD724 RGB to NTSC/PAL Encoder. The results so far are quite encouraging - no streaking or noise, and of course no pixel distortion because the signal is going through the RGB GAL. The encoder circuit draws about 35mA, about the same as the THS7314 video buffer.

 

For this test I used an external 14.318MHz oscillator, which introduced some shimmer due to not being phase locked to the Aquarius. Next I will try using the Aquarius internal 3.57MHz clock. The AD724 can also output S-video, which should produce an even better picture on TVs which have S-video input.

 

Though the AD724 encoder could be added to my RGB board it might be better as an external add-on, then it could be used with other devices. This could have its own oscillator (perhaps with both NTSC and PAL crystals) or use the Aquarius 3.57MHz clock (NTSC only) fed through the RGB connector.

 

Now that I know how good composite video can be, I will also investigate further to see whether the streaking and noise on the stock Aquarius composite signal can be reduced.

 

Any plans to sell the RGB mod, for use with Intellivision?

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Any plans to sell the RGB mod, for use with Intellivision?

I don't have an Intellivision (and no way of getting one) so I cannot test it. However since I have couple of spare boards and enough parts, I am happy to sell you one at cost on the understanding that there is no guarantee it will work properly in the Inty. Do you have the skills and equipment to install it and work through any problems that might occur? Are you willing to be a 'beta' tester?

 

Cost of PCB with parts installed (no wires or connectors):-

PCB $7

GAL22V10 (programmed) $4

24 pin IC socket $1

10 x smd resistors, 2 x caps $3

Total component cost: $15

 

If it will fit in an envelope (max. thickness 10mm) then postage will be $5, for a total of $20.

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I don't have an Intellivision (and no way of getting one) so I cannot test it. However since I have couple of spare boards and enough parts, I am happy to sell you one at cost on the understanding that there is no guarantee it will work properly in the Inty. Do you have the skills and equipment to install it and work through any problems that might occur? Are you willing to be a 'beta' tester?

 

Cost of PCB with parts installed (no wires or connectors):-

PCB $7

GAL22V10 (programmed) $4

24 pin IC socket $1

10 x smd resistors, 2 x caps $3

Total component cost: $15

 

If it will fit in an envelope (max. thickness 10mm) then postage will be $5, for a total of $20.

 

 

Sounds great. I have several Intellivision consoles and happy to test. If it doesn't work, no worries.

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I don't have an Intellivision (and no way of getting one) so I cannot test it. However since I have couple of spare boards and enough parts, I am happy to sell you one at cost on the understanding that there is no guarantee it will work properly in the Inty. Do you have the skills and equipment to install it and work through any problems that might occur? Are you willing to be a 'beta' tester?

 

Cost of PCB with parts installed (no wires or connectors):-

PCB $7

GAL22V10 (programmed) $4

24 pin IC socket $1

10 x smd resistors, 2 x caps $3

Total component cost: $15

 

If it will fit in an envelope (max. thickness 10mm) then postage will be $5, for a total of $20.

 

Hey Bruce, if you would tolerate another beta tester I'd love to get hold of one for my NTSC Intellivision as well. I did an RGB mod on one of mine using another board successfully, but it has color issues. I'd love to try another.

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Hey Bruce, if you would tolerate another beta tester I'd love to get hold of one for my NTSC Intellivision as well.

I am happy to have another beta tester. However grips03 is having some problems with his board (it only works when the PCB is severely flexed, and 2 resistors are bad) so I would prefer to wait until this has been resolved before sending out another one. From now on I will ship via parcel post only (an extra $10) to lessen the risk of damage. I will also make a test circuit to ensure that it works 100% before shipping!

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I am happy to have another beta tester. However grips03 is having some problems with his board (it only works when the PCB is severely flexed, and 2 resistors are bad) so I would prefer to wait until this has been resolved before sending out another one. From now on I will ship via parcel post only (an extra $10) to lessen the risk of damage. I will also make a test circuit to ensure that it works 100% before shipping!

 

Sounds fine to me, Bruce. Let me know when you're ready. You can PM me here on AA.

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This is color on PVM 8042. Its pretty good colorwise and very sharp. Background color gray is a little bit reddish.

 

If connected to XRGB2 then colors are way off. Going to change resistors to pots and try to get colors good for both PVM and XRGB2.

 

I can share here if people want to follow. I'm using NTSC Intv 1 (2609).

post-27883-0-70522500-1509576004.png

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This is color on PVM 8042. Its pretty good colorwise and very sharp. Background color gray is a little bit reddish.

 

If connected to XRGB2 then colors are way off.

Does this mean you fixed the problem you were having with wrong colors? If the color is good on a normal monitor it should be similar on the XRGB, unless it has different terminations (should be 75 Ohms to ground on the R G and B lines. If it doesn't have this then you may need to add resistors, and perhaps buffer amps to maintain the correct signal level and impedance).

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Cool, this is looking to be like an awesome project! I'm also up for testing if you need an extra guy when some of those issues are ironed out.

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This is a neat project! How are things looking on the Intellivision side of this project? I just ordered a Framemeister and RGB upgrades for my 2600 and NES, but what I really want is RGB output from my favorite console. :)

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I'd love to buy at least one of these for Aquarius and Intellivision each! It seems it was working completely for Aquarius, at the very least. I realize you wanted to perfect the composite signal, but I'd be happy with it the way it is, as I'm more interested in RGB.

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13 minutes ago, pedalpowered said:

I'd love to buy at least one of these for Aquarius and Intellivision each! It seems it was working completely for Aquarius, at the very least. I realize you wanted to perfect the composite signal, but I'd be happy with it the way it is, as I'm more interested in RGB.

I'm sure we'll see an RGB upgrade of some sort, at least for the Aquarius.  In the meantime, you might consider the new Composite Video Adapter Board.

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Thanks! Yes, 1stage's board is what led me to find this. It seems that the prolific Bruce has not graced AA with his presence in over a year. Tis a shame, b/c this RGB board really worked and so did his brilliant Micro-Expander!

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On 9/24/2017 at 5:16 PM, Bruce Abbott said:

Aquarius internal 3.57MHz clock

Uh I know this is a dead thread but the Aquarius doesn't seem to have a 3.57MHz clock; at least the one I have doesn't.

The tea1002 divides the 7.15909MHZ clock by 2.5 giving 2.863636MHZ.

If you want to get 3.579545MHZ you need to divide the clock going to PLA1/U7 by 2 (this is pin 2).

I'm going to see what this gives me for video on my own circuit but the 2.8MHZ clock seems unusable for my uses,. and I am not sure why it is such a weird value.

 

Just figured that info may help someone in the future.

 

So I tested this in the middle of writing this out:

Here is what I have https://i.imgur.com/5yG42zO.jpg

On further review it seems that I have an error someplace. Nothing that I can't fix. This is just a proof of concept.

Anyway, that is driven with the 7.15909MHZ clock. I don't know the ramifications if any of running 2X an NTSC clock.

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1 hour ago, the_crayon_king said:

Uh I know this is a dead thread but the Aquarius doesn't seem to have a 3.57MHz clock; at least the one I have doesn't.

The tea1002 divides the 7.15909MHZ clock by 2.5 giving 2.863636MHZ.

If you want to get 3.579545MHZ you need to divide the clock going to PLA1/U7 by 2 (this is pin 2).

I'm going to see what this gives me for video on my own circuit but the 2.8MHZ clock seems unusable for my uses,. and I am not sure why it is such a weird value.

 

Just figured that info may help someone in the future.

 

So I tested this in the middle of writing this out:

Here is what I have https://i.imgur.com/5yG42zO.jpg

On further review it seems that I have an error someplace. Nothing that I can't fix. This is just a proof of concept.

Anyway, that is driven with the 7.15909MHZ clock. I don't know the ramifications if any of running 2X an NTSC clock.

Depending on if you have an NTSC or PAL system,  the NTSC takes the DOT clock (pin 2 U6) from the 7.159Mhz on the TEA /2 this is then further divided to give 3.58Mhz sys clock on the z80.
If you have a PAL system, then the Xtal on the TEA is an 8.433Mhz and this is irrelelvant to the system for normal operation, there is a 74LS04 with a 7.15909Mhz xtal that produces the DOT clock.

The system clock is 100% 7.15909Mhz /2 in both PAL & NTSC

I'm guessing your misunderstanding is from the /2.5 in the TEA that outputs on pin 17 (which is not used in the Aquarius at all).

Edited by MackJsy

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1 hour ago, MackJsy said:

Depending on if you have an NTSC or PAL system,  the NTSC takes the DOT clock (pin 2 U6) from the 7.159Mhz on the TEA /2 this is then further divided to give 3.58Mhz sys clock on the z80.
If you have a PAL system, then the Xtal on the TEA is an 8.433Mhz and this is irrelelvant to the system for normal operation, there is a 74LS04 with a 7.15909Mhz xtal that produces the DOT clock.

The system clock is 100% 7.15909Mhz /2 in both PAL & NTSC

I'm guessing your misunderstanding is from the /2.5 in the TEA that outputs on pin 17 (which is not used in the Aquarius at all).

That unused clock was indeed the source of my confusion.

 

Thank you for the information. I may have been unknowingly practicing Cunningham's Law.

It appears like pin 31 might be the clock I am after (looking at the schematic). I will check that later.

 

Anyway sorry for the misinformation but I did make progress:

YPbPr

RGB

 

I will make my own thread for this. Thanks again.

Edited by the_crayon_king

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