Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ucsdhub!esosun!seismo!uunet!pcrat!rick
From: rick@pcrat.UUCP (Rick Richardson)
Newsgroups: comp.unix.microport
Subject: Re: serial ports on the '286
Keywords: uport SV/286
Message-ID: <554@pcrat.UUCP>
Date: 13 Aug 88 16:06:06 GMT
References: <531@micropen> <4690@b-tech.UUCP> <5909@bigtex.uucp> <532@micropen>
Reply-To: rick@pcrat.UUCP (Rick Richardson)
Organization: PC Research, Inc., Tinton Falls, NJ
Lines: 24

In article <532@micropen> dave@micropen (David F. Carlson) writes:
 
>> For example, let's suppose uPort modified the serial driver such that
>> when the line was put in raw mode, the 16550AN was set to generate an
>> interrupt every tenth character.  The interrupt handler would then get
 
>But raw mode is defined (often) to return in *less* than 10 characters.
>The "win" of the fifo is that overruns are nearly impossible, which allows
>the driver to make interrupt latency almost a non-issue.  Getting in and

But the 16550A will automatically timeout and generate the interrupt
for less than N characters if something is in the FIFO and it has
been idle (I think) 4 character times.






-- 
		Rick Richardson, PC Research, Inc.

(201) 542-3734 (voice, nights)   OR     (201) 389-8963 (voice, days)
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