Date: Sat, 07 Jan 1995 22:44:23 -0500 (CDT)
From: Aaron Ucko <UCKO AT VAX1 DOT ROCKHURST DOT EDU>
Subject: Re: timer int
To: OKRA AT max DOT tiac DOT net
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Organization: Rockhurst College; Kansas City, MO

Here are a couple ideas that come to mind:
* Would it be at all practical to poll the video card, or would doing so
  interfere excessively with the other stuff your program's doing?
* Use the (surprisingly obscure) Real-Time Clock chip, which originated
  with ATs and their CMOS.  It allows, among other things, a program to
  receive a relatively frequent (up to 8192 times a second) periodic
  interrupt.  Unfortunately, the frequency must be a power of two, so
  you have to choose between 64 and 128. [Aside: it also has a somewhat
  limited `cron mode' which lets you have an interrupt 17 seconds after
  each minute between 2 and 3 AM, e.g.]  Programming it is a bit complicated,
  so I'll send you details in a later message.  [Anyone else interested?
  I'd rather not send it to the whole list if most people don't care...] 

--- Aaron Ucko (ucko AT vax1 DOT rockhurst DOT edu; finger for PGP public key) -=- httyp!
-=*=-Just because you're paranoid doesn't mean they aren't out to get you.-=*=-
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