Path: utzoo!mnetor!tmsoft!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!altos!gumby!jerry
From: jerry@gumby.Altos.COM (Jerry Gardner)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Interrupt Driven Serial IO...
Message-ID: <4688@gumby.Altos.COM>
Date: 7 Feb 91 17:32:17 GMT
References: <8871@hub.ucsb.edu>
Reply-To: jerry@altos.COM (Jerry Gardner)
Distribution: comp
Organization: Altos Computer Systems, San Jose, CA
Lines: 17

In article <8871@hub.ucsb.edu> gnome@cornu.ucsb.edu writes:
[ He wrote an interrupt-driven terminal program that loses characters ]

Are you buffering the serial data as it comes in?  If I remember correctly,
the PC UART chip has a two byte receive FIFO.  If you don't get around to
reading it quickly enough, characters will be lost as others come in.

The correct technique is to store the buffers in a ring buffer in the
interrupt handler and write them to the display later.  My program uses
a 512 byte receive ring buffer and I've never lost characters.  


-- 
Jerry Gardner, NJ6A					Altos Computer Systems
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Internet: jerry@altos.com				San Jose, CA  95134
Guns don't kill people, bullets do.                     (408) 432-6200