80col+EGA-stuff TI-99/4A - TMS9938/9958: 80 Col & Enhanced Graphics HW&SW

[globeron]

Yesterday my father had the honour to get the 80-Column card to work (we removed "extra wiring" which I will put in the next message in this thread)

we compared dip-switch settings, etc.

 

Assuming that the card always worked is that my guess is that the TV (SCART / RGB) is the one that fixed it (and my VCR-SCART is not

reading the signals correctly). The other option is the home-made cable (but I checked that a few times with Ralf) and I got a white dot moving

(which looked like a Synchronisation problem).

 

80-Column card is the device at the right side (plugged into the side-slot of the TI-99/4A) and requires 5V power adapter.

This 80-Col card has been adjusted with a power switch at the front.

 

Result:

[globeron]

The 80-Col card came with some components soldered to it

1. power switch at the front with wiring

 

Right 2x wires (red and black) and PCB-board has a cut/disconnect

 

 

 

 

2. some resistors ? (no clue what the purpose is, but there was 1x wire to the video-chip)

We removed all these first, before plugging it in (so these were not needed to get the card to work)

 

4x wires in total (I forgot to make a picture of the resistors)

 

 

 

 

Question: anyone has an idea why it would be beneficial ?

 

 

 

3. Some extra wiring and component, no clue what the purpose is

 

 

 

 

Question: I think it goes into the Video-chip location, but then you cannot plug something on top of it

 

Any clue ?

[+mizapf]

The TMS9928a in the console delivers the GROMCLK and VDPINT signal. As you remove that circuit, you must get it from somewhere else. This is done by the external video card. You can plug in that socket into the VDP socket in the console.

 

I know because I had that issue in the last release of MAME/MESS when I moved the v9938 where it actually resides, and then I had to create something very similar to those external cables.

[globeron]

Thank you Michael!

 

Is it very important? (because the other 80 col. card does not have it, and it seems to work okay without these cables)

What would be the behavior / risk without having these "GROMCLK and VDPINT signal" ?

 

 

When I compared the 80 Col. cards, I noticed a difference in components (e.g. newer software version) and some other

electrical components (but probably these have the same function).

[+mizapf]

Is it the EVPC? Or the EVPC2? Or another card?

 

The problem is that without the VDPINT there is no 60Hz interrupt anymore, in particular no sound, no sprite movement, no QUIT key. And without the GROMCLK the GROMs won't work, so it's pretty important.

 

Later developments (EVPC2) included a separate unit (Replx99) that was used plugged into the empty VDP socket to deliver these signals.

[+Schmitzi]

The Pics here are taken from the Mechatronik 80 ZK

[+Schmitzi]

New Software

 

 

Editor/Assembler III and EDIT1 (40/80col) v1.4 by Fred Kaal

 

 

http://www.ti99-geek.nl/

[Omega-TI]

New Software

 

 

Editor/Assembler III and EDIT1 (40/80col) v1.4 by Fred Kaal

 

 

http://www.ti99-geek.nl/

 

Have you tried this yet? I've been very happy with the FlashROM 99 version of EAII with v1.3 of the 80 column editor.

What's so different?

[+jedimatt42]

 

Have you tried this yet? I've been very happy with the FlashROM 99 version of EAII with v1.3 of the 80 column editor.

What's so different?

 

Fred modified his EA II to parameterize how it loads Edit1, so it can be in 40 or 80 column mode. So the same image can be used on F18A or 9938 systems in 80 column mode, or stock 9918 systems in 40 column mode. He also indicated that there are some additional keyboard shortcuts added to the editor.

 

The editor keeps the text buffer resident when you go back to the menu where you select load/edit 40/edit 80/save/purge... so you can actually switch between the 40 and 80 column editor without losing data as well. That is kind of slick, as even on an 80 column capable 4a, you might want to create text data that looks easy to read for 40 column TI users...

 

-M@

[+Schmitzi]

Hi,

 

there is a new update on Fred Kaal´s hompage, the Editor/Assembler III r2 module with 40/80 column EDIT1 v1.5

 

(just klick on "Site history" on the left pane)

 

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