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F18A


matthew180

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The F18A, without using any of the advanced features, makes a huge difference in the display quality of my trusty TI. Now I want one for my Coleco Adam.

 

And as I look around my vintage computer collection, I see some machines that I would love a similar type of product for.

 

A Vic-II chip replacement could be a big market with everyone using a C64 or C128 a potential customer. I would buy one for my 128D, especially if it allowed the 40 column display to continue showing output while the computer was in "fast" mode (the Vic-II would only operate at 1Mhz slow mode). Another enhancement would be to also bridge over to the other graphic chip in the 128 used for 80 column display and be able to have both output on the same VGA connector, perhaps toggling the output via the 40/80 key on the keyboard. That last I would gladly pay extra for.

 

Another computer that really needs the ability to output on modern displays is the Amiga. I love this machine, but the varying frequencies of the output make it hard to use anything other than an old multisync monitor that can do 15Khz as a minimum. There are "flicker fixers" that attempt to buffer the display, but they are limited in what they can do. I'd love to use my Amiga 1200 on an LCD monitor with any of the modes that computer is capable of (including NTSC and PAL).

 

So Matthew, can you have those done up for me next month? I can send you a couple of bucks to get started!

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Another computer that really needs the ability to output on modern displays is the Amiga. I love this machine, but the varying frequencies of the output make it hard to use anything other than an old multisync monitor that can do 15Khz as a minimum. There are "flicker fixers" that attempt to buffer the display, but they are limited in what they can do. I'd love to use my Amiga 1200 on an LCD monitor with any of the modes that computer is capable of (including NTSC and PAL).

 

Check out the Indivision ECS and Indivision AGA.

 

INDIVIDUAL COMPUTERS [ jens schoenfeld ] GmbH

http://www.jschoenfe...s/news130_e.htm

 

Amiga Hardware Database - Individual Computers Indivision AGA 1200 / Indivision AGA 4000

http://amiga.resourc...p/indivisionaga

 

You apparently do not hang around some of the Amiga forums, so check out http://amiga.org as a starting point.

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Thanks! My Amiga 1200 is currently torn apart and will require a lot of attention from me for a period of time to get it setup back into a way I am happy with. I am in a big project right now of re-arranging my entire vintage computer and game console setup and I just had to start with my TI. I'm getting along fairly well and will soon be hopping back into the Amiga scene. So yes, you're right, I have been a bit out of touch with the Amiga forums. I see though that the Indivision AGA MK2 is out and solves my issues with video output. I'm looking at about $175 CDN after shipping, so for the features it gives me and the problems it solves with the original output I think I'll be ordering it soon.

 

So Matthew, now your job is simpler, I only need an updated VIC-II and 8563 VDC chip for my 128.

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I am in a big project right now of re-arranging my entire vintage computer and game console setup and I just had to start with my TI. I'm getting along fairly well and will soon be hopping back into the Amiga scene. So yes, you're right, I have been a bit out of touch with the Amiga forums.

 

Welcome back, on all fronts.

 

So Matthew, now your job is simpler, I only need an updated VIC-II and 8563 VDC chip for my 128.

 

This would be a bit of an undertaking, and probably a great challenge for someone to take up. Since each socket is decoded (that is, not all address lines are available at each chip, and each chip is *CS activated,) a single-chip solution would probably not work. IIRC, and I have not looked at the schematics in a while, all address lines are available at the cartridge port so one could possibly build for there and just snarf the bus signals into a single-chip solution. Remembering, also, that the VIC-II is directly addressed and addresses system RAM while the VDC is register-fed with its own memory similar to the 9918, so the on-board VIC-II would need to be disabled to prevent memory access conflicts. The VIC-II could not simply be removed as it provides system timing. Yes, a 128/128D with 2MHz-capable 40 column mode would be nice, a faster VDC without the bugs and maybe with more addressable memory could be handy, as well.

 

Sadly, I do not think an upgraded VDC would have the same marketability as the F18A. A replacement VIC-II should considering the number of 64/128s out there (and there is already an SOC of the C64 with a vastly extended VIC implementation,) but the 128's 80 column mode and VDC were sorely under-utilized, not to mention severely niche. The F18A, OTOH, works in a multitude of systems and gets a hella workout.

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@jstimson: I'm glad the F18A is working out for you! Any feedback is greatly appreciated. Also, if you do plan to put one in your ADAM soon, wait until you see the "ADAM Adapter" on my website. I was putting an F18A into an ADAM last week, and although it works fine electronically, I realized the F18A goes outside the motherboard footprint and you cannot close the case. I whipped up an "offset adapter board" and sent out to have a few made. I should have them soon, get them tested, and have them available on my website. Cost should only be about $10.

 

As for doing video solutions for other systems, probably won't happen from me. The F18A took 2-years to produce, and the second year I put in a ton of time on it (the first year I was just poking at it a few weeks here and there). It is easy to do a "one-off" for yourself as a hobby, but very hard to actually produce a finished product that people can just buy and plug in.

 

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Hi Matthew !

 

this is my contribution to introduce in Italy the card that you have built.

choice the correct flag on the top-right in home page for your language (google) translation ;)

 

 

I hope you will glad for it. I am very happy with my F18A;)

 

http://www.ti99iuc.i...ticoli&Itemid=2

 

Thank You for all ! ;)

Edited by ti99userclub
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The ROW30 setting can be set in any mode and basically extends the name table, thus it retrieves and displays more data. It should work find in MCM, and I'm pretty sure I tested it, but I can't find the screen shot right off hand.

 

That's great... and terrible at the same time!

I was about to finish with Multicolor mode... and you're telling me that this can be improved !

Argh....

 

Guillaume.

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  • 2 weeks later...

The ROW30 setting can be set in any mode and basically extends the name table, thus it retrieves and displays more data. It should work find in MCM, and I'm pretty sure I tested it, but I can't find the screen shot right off hand.

 

Hello Matthew,

 

Multicolor mode + line30 is finished and works great, but I still have a problem hard to debug directly on the TI99.

So I have one question: When the computer is set in Multicolor mode, does the F18A automatically fill the Screen Image Table with the required values? (4 times bytes from 0 to >1f, then four times from >20 to >3f etc).

 

Thanks,

 

Guillaume.

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I can't speak for Matthew but I would be very surprised if it did. You don't want your video chip writing into RAM by itself, maybe over the top of important data!

 

Why I ask this is because when setting multicolor + line 30 a sprite appears! So I suspect that the screen image table starting at >0000 is overwritten and that more bytes (after >300) are written.

Because I change the screen image address AFTER that!

I could do it before, but my routine is complex enough, used for every other screen mode with a table. So I wouldn't like to change everything if I'm not on the right way to the solution...

 

Guillaume.

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I can't speak to 30 row mode specifically, but remember that setting up multicolor as you describe is just a recommendation -- it's still a lookup table and you can put any character anywhere (in fact I take advantage of that in my "half-multicolor" mode so that bitmap and multicolor can share a table). Anyway, it means it wouldn't make sense for the VDP to automatically initialize tables in VRAM - that could destroy previously written data. :)

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I can't speak to 30 row mode specifically, but remember that setting up multicolor as you describe is just a recommendation -- it's still a lookup table and you can put any character anywhere (in fact I take advantage of that in my "half-multicolor" mode so that bitmap and multicolor can share a table). Anyway, it means it wouldn't make sense for the VDP to automatically initialize tables in VRAM - that could destroy previously written data. :)

 

Sure, but when using my program with Classic99:

1) without line30 option: everything is Ok

2) with line30 option everything is still Ok even if I only can see the first 48 lines. But no sprite appears, my routines don't seem to overwrite the sprite tables

 

WIth the real TI

1) without Line 30 ok

2) with line30 : a sprite appears ! So something more happens with the F18A.

 

Guillaume.

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Well, probably Classic99 is at fault... but until Matthew speaks up, it might help theories to know what you have in each register and which address the tables are located at? :)

 

Yes! good idea. Things are set in this order:

 

VR6 = 0, sprite descriptor table at >0000 (normal for XB)

VR4 = 2, pattern descriptor table at >1000

VR57=28 twice to enable the extended registers

 

then the Screen Table is prepared at >1800

 

VR3 = >20, color table normal position in XB

VR49 = >40 for Line30

VR0 = 0 no bitmap mode

VR1=>E8 16k/blan enable/inter enable/no text mode //multicolor/0/0/0

a copy of VR1 in >83D4

VR2 = 6 Screen image table at >1800

 

And that's all...

Guillaume.

Edited by moulinaie
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VR6 does not look correct. The screen begins at 0 in both TIB and XB.

 

Edit: Ah! But I forgot about the weird 96 ASCII offset thing in TI & XB.

 

This could still be the source of your problem though. IIRC, in TIB and XB the screen image table and the sprite table effectively overlap (i.e. they are on top of each other). That is why there is the weird ASCII 96 offset.

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What about VR5, the Sprite Attribute Table (SAT) location? Remember, when you enable ROW30, the name table is larger (i.e. the F18A reads more data from the name table to display the extra 6 rows) depending on the mode. If the SAT is located in VRAM immediately after the name table, then you may be writing into the SAT when you enable ROW30 and write to the extra 6 (or 12 in MCM) lines.

 

The F18A does not do any VRAM modifications on its own. The only ways to change VRAM are:

 

1. power cycle the computer

2. write data to the F18A's write port

3. write a GPU routing that changes VRAM

 

ROW30 is not a *mode*, it is just a flag that basically changes the internal line counter (and top/bottom margins).

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What about VR5, the Sprite Attribute Table (SAT) location? Remember, when you enable ROW30, the name table is larger (i.e. the F18A reads more data from the name table to display the extra 6 rows) depending on the mode. If the SAT is located in VRAM immediately after the name table, then you may be writing into the SAT when you enable ROW30 and write to the extra 6 (or 12 in MCM) lines.

 

Remember that Screen image table is moved to >1800 (VR2 = 6) and Pattern descriptor table is moved to >1000 (VR4 = 2)

So, nothing else should overwrite the sprites satble.

 

Can I send you my *.DSK file for you to test my program on your hardware? Maybe, as my CF7 i having problems, something happens that has nothing to deal with the F18A.

 

Guillaume.

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