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TIM v9958 video upgrade for the TI-99/4A


RickyDean
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3 hours ago, RickyDean said:

Answers:

1) OPA owner and developer is in federal custody, he left Canada years ago to escape prosecution, but was apprehended and brought to trial in America a couple of years ago.

2)Schematics and plans are not readily available, just some pictures. It can be and has been reverse engineered, by one individual,  but not for profit. The video chip may not be easy to find, and the secondary unit,  the OS replacement board, the Son of a Board was closed source. It can be emulated, by other devices like the Gram Kracker.

Not at all simple then. Thank you for the info, I had nooo idea.

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40 minutes ago, Tursi said:

The F18A is a 9918A replacement designed to provide a better video output. Enhancements were made to it because they could be, but they are done in such a way that the F18A is substantially more compatible with 9918A software than the 9938 or 9958. (Basically, they are locked out until a particular sequence happens.) At the same time, it has just enough compatibility to provide the 80 column mode in software that doesn't need the extra video RAM, which was the main feature that most users really wanted. ;)

 

So not many were ever produced, which in itself limits software and continued support.

 

So in a modern day, practical sense the F18A is the way to go. Thanks Tursi.

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I once upon a time stuck a TIM board in my Coleco ADAM and got it to work (that was a strapping option on the TIM board and plans were apparently in place to support the ADAM). The issue is that the 9958 upon initialization has a set of palette registers not found on the 9928/9918 that you have to program for there to be any video output. Otherwise, all output is black on black! I wrote a small program to initialize these registers on the ADAM and it worked. I suspect that's probably all that's in the SOB otherwise you'd likely also get a blank/black screen on the TI.

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4 hours ago, Geoff Oltmans said:

I once upon a time stuck a TIM board in my Coleco ADAM and got it to work (that was a strapping option on the TIM board and plans were apparently in place to support the ADAM). The issue is that the 9958 upon initialization has a set of palette registers not found on the 9928/9918 that you have to program for there to be any video output. Otherwise, all output is black on black! I wrote a small program to initialize these registers on the ADAM and it worked. I suspect that's probably all that's in the SOB otherwise you'd likely also get a blank/black screen on the TI.

That was a problem with many of the 80-column boards using the 9938/9958. I've actually got a few test boards of a 9938 equivalent to the TIM, but I still have to build/test them. . .

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5 hours ago, Geoff Oltmans said:

I once upon a time stuck a TIM board in my Coleco ADAM and got it to work (that was a strapping option on the TIM board and plans were apparently in place to support the ADAM). The issue is that the 9958 upon initialization has a set of palette registers not found on the 9928/9918 that you have to program for there to be any video output. Otherwise, all output is black on black! I wrote a small program to initialize these registers on the ADAM and it worked. I suspect that's probably all that's in the SOB otherwise you'd likely also get a blank/black screen on the TI.

I met someone at a computer meet in Ottawa back in the 90s who was also excited about getting a TIM for his Adam, so they were definitely collecting money for it! :)

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