Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!elroy.jpl.nasa.gov!jato!vsnyder
From: vsnyder@jato.jpl.nasa.gov (Van Snyder)
Newsgroups: comp.sys.atari.st
Subject: Re: Overscan in monochrome
Message-ID: <1991Feb20.004157.14406@jato.jpl.nasa.gov>
Date: 20 Feb 91 00:41:57 GMT
Reply-To: vsnyder@jato.Jpl.Nasa.Gov (Van Snyder)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 12

Does anybody know what signal is on pin 10 of the RF modulator in an old (rev
B board) 520ST?  It also appears on pin 2 of the monitor jack.  I tried using
it for Overscan, but it didn't work, so I assume it's not composite synch.

There's enough unused logic in my ST to compute composite synch without adding
two diodes, a resistor and a transistor:  U14 has a spare 2-input NAND, U40
has a spare 2-input NOR, and U35? has two spare invertors.  That's ALMOST
enough to control Overscan with GPO instead of a switch.
-- 
vsnyder@jato.Jpl.Nasa.Gov
ames!elroy!jato!vsnyder
vsnyder@jato.uucp