Re: VECTREX

----- Original Message -----
From: "Tek" <mypearl@dds.nl>
To: <vectorlist@synthcom.com>
Sent: Wednesday, September 13, 2000 6:07 PM
Subject: VECTOR: VECTREX

> Well Neil... I hope this is okay for the list since it is not about an
arcade
> game, but the only home vector system... the VECTREX.
> Anyway, here we go.
>
>
> I just got a Vectrex system from a fiend of mine. Normally I work with
Atari
> Vector games like Tempest or Starwars, and he knew I was into Vector games
:)
>
> Anyway, it was broken to start with. Some probing showed the 6522 was shot
and I
> replaced it. Now everything works fine, except for one strange thing:
Every
> second letter of any text shown in minestorm (don't know what happens when
I use
> a cart since I do not have one yet) is blank! nothing!
>
> The only cause I can think of is a stuck lower address line, but since
there is
> only one ROM which stores more than just plain text, this can't be really
true.
> My logic analyzer shows it is indeed still alive. When I check the content
of
> the ROM by looking at an image from an emulator for the Vectrex, you can
see
> the display texts are scattered around the ROM . This leads me to the idea
it
> really cannot be an adressing problem. Also high scores are crippled and
they do
> not come from ROM but RAM, is it?
>
> Does anyone have a clue were to look next?
>
> Another thing I don't understand how the Vectrex 'draws' the vector. In
the
> normal vector stuff, as you all know, there is a separate 'vector
generator'
> with it's own instruction set, RAM and ROM, vector counters ect ect. The
game
> processor only has to send a bunch of co-ords and the vector generator
will do
> it for it. (basically).

Check in rec.games.vectrex but I can tell you a little bit which might help
you. The text is put into
some kind of buffer and then a line-by-line assessment is made on how to
draw it "rasterized".
so if you had an equals sign and a space and an equals sign and each letter
is made up of 6 rows (I can't remember the exact number of rows), the
calculation would say "draw no vector for the 1st line, draw a dash, a space
and a dash for the second line, draw no vector for the 1st line and go back
2 steps and repeat". In other words, it can't be something in the vector
draw stuff; it must somehow be something in the addressing of that area of
ROM.

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Received on Wed Sep 13 22:03:45 2000