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- From: troyer@finmark.nynexst.com (Tom Royer)
- Subject: Can anyone help me with this...
- Message-ID: <TROYER.92Nov10140501@finmark.nynexst.com>
- Sender: news@nynexst.com (For News purposes)
- Organization: /u/troyer/.organization
- Distribution: sci
- Posting-Front-End: GNU Emacs 18.55.2 of Tue Mar 20 1990 on oberon (berkeley-unix)
- Date: 10 Nov 92 14:05:01
- Lines: 34
-
- Hello,
-
- I am trying to design a development system for the Vectrex game machine.
- This is basically an eprom emulator of sorts. Here is an excerpt from a
- message I posted to rec.games.vectrex:
-
- > I'm still trying to get an Amiga<->Vectrex interface running. It's
- > based on Jeff Lavin's dual-port RAM development schematic. After much
- > frustration, I did this as an isolation test: I have build eprom and
- > multi-game carts, so I am confident that my pinout knowledge is correct.
- > I hacked a cart by removing the rom and adding a short ribbon cable with
- > a 34-pin header on the other end. On a wire-wrap board I connected the
- > header-socket to an eprom socket. Now, if I power the eprom from the
- > vectrex, the vectrex will run the eprom. From this I can conclude that
- > the hacked cart/ribbon assembly is okay (the ribbon cable is only 2-3
- > inches long, BTW). If I try to power the eprom externally, however, the
- > vectrex freezes. I have connected all the grounds together properly. I
- > also disconnect the power lines from the vectrex when I try this, so I'm
- > not connecting the +5 of the vectrex to the +5 of my power supply or
- > anything silly like that. I don't understand why this is not working.
- > The vectrex just seems to refuse signals powered from an external
- > source.
-
- The cartridge port of the Vectrex basically has the data and address lines
- that go directly to a 68A09 inside. The eprom I used was a 27C64. The
- interface I'm designing will have 13 or so chips on it including a 32K sram.
- I doubt I can power the entire thing off of the Vectrex console - this is why
- I want to use an external power supply.
-
- I'm not sure if I've included enough info here, but if anyone has any clues,
- this soldering-iron-wielding-software-engineer would greatly appreciate it.
-
- -Tom Royer
- troyer@nynexst.com
-