porter@inuxd.UUCP (J Porter) (03/14/84)
For the benefit of the new VECTREX owners, here is an article that was posted to the net this past fall. From inuxc!ixn5c!ihnp4!ihnss!knudsen Thu Sep 22 18:30:46 1983 Relay-Version: version B 2.10 5/3/83; site inuxd.UUCP Posting-Version: version B 2.10 5/26/83; site ihnss.UUCP Path: inuxd!inuxc!ixn5c!ihnp4!ihnss!knudsen From: knudsen@ihnss.UUCP Newsgroups: net.micro.6809 Subject: Some Vectrex info Message-ID: <1702@ihnss.UUCP> Date: Thu, 22-Sep-83 18:30:46 EST Article-I.D.: ihnss.1702 Posted: Thu Sep 22 18:30:46 1983 Date-Received: Fri, 23-Sep-83 21:33:50 EST Organization: BTL Naperville, Il. Lines: 46 [This was posted a while back in the games group. Those interested in digging into their Vectreces (Vectrexen?) should find it a good starting point. I've poked around in mine and discovered a few things that I will share when I get time. Take a lesson from the Coco-nuts, and start disassembling that ROM. If God wanted us to get info from manufacturers, He wouldn't have given us logic analyzers, etc.} From: halbert@ucbvax.UUCP Newsgroups: net.games.video Subject: Re: Vectrex Date: Thu, 9-Jun-83 02:10:50 CDT Jay Smith III, president of Western Technologies, Inc., which designed the Vectrex (and lots of other toys and games) gave a talk at Xerox PARC a few months ago. Part of the talk was a detailed description of how the Vectrex works. It has: a 6809, one 8-bit DAC, and a PIA (?) to steer the DAC output to 3 sample-and-holds, one for X, one for Y, and one for intensity. The PIA also can steer the DAC output to a comparator and directly to the audio system, bypassing the GI sound chip which is used normally. This direct audio input could be used for speech synthesis. There are 2 integrators for X and Y. The integrators ramp up to draw lines. The ramping speed is variable. If the ramping time is shortened, shorter lines will be drawn. Thus zooming is really easy. Lines are drawn relative to the previous beam position. After 12-15 lines are drawn, things may start to get off, so the system recalibrates by resetting the origin to 0,0, which is done by shorting the integrators. The comparator is used to read the input potentiometers, by asking the DAC to produce various output levels and comparing them with the voltages across the pots. The plug-in cartridge address lines are wide enough to address 32k ROMs straightforwardly. This is a very clever design. They were very good at minimizing parts count and still providing lots of flexibility. --Dan