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From: josephc@nntp-server.caltech.edu (Joseph Chiu)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: 16550
Message-ID: <1991Jun8.165419.2020@nntp-server.caltech.edu>
Date: 8 Jun 91 16:54:19 GMT
Article-I.D.: nntp-ser.1991Jun8.165419.2020
References: <5080@orbit.cts.com> <31550001@hpcndpc.CND.HP.COM>
Organization: California Institute of Technology, Pasadena
Lines: 32

lts@hpcndpc.CND.HP.COM (Lou Schulte) writes:

>> Why are these UARTs [16550] so popular it seems, that I see them mentioned all
>> ofer the place for people looking for them for their pc's?
>> I'm going to be hacking up a couple serial ports into my machine, and was
>> wondering what they offer over the 8250 that is standard?

>The 8250 buffers just a single byte whereas the 16550 has a multibyte FIFO. So
>if you have interrupt lockouts exceeding the one-byte transmission time (about
>1 msec at 9600 baud) you'll lose bytes with the 8250 but not with the 16550.
>Also, as I understand it, the 16550 is a direct replacement for the 8250.

>Lou Schulte

Speaking of UART's, I have noticed that my "AT-Serial Card" does not use
16450/16550's, but rather a chip numbered 82450.   I suspect it's supposed
to be a relabeling of the 16450 number, but does anyone know for sure?

By the way, if anyone is interested, I got this AT I/O card with TWO serial
ports, Parallel port, and Joystick port for 14.00; not a bad deal, except
the chips are not socketed, so I can't pull out the old UART's to replace
it with the 16550.  (And a joystick for $10.00, and a mouse for $13.00, and
RS-232 tester for $7.00... and on and on...  Amazing what happens when you
whittle your insomnia by thumbing through Computer Shopper...  : (    My
$14 purchase grew to almost $90!)

   -- Joseph

-- 
Joseph Chiu, Dept. of Computer Science, Caltech | Rrr Redundant Tautology System
1-57 Fleming House, Caltech, Pasadena, CA 91126 | Ttt Triplicate Archival Backup
Tel/Fax:(818) 585-0393 josephc@coil.caltech.edu | Sss RTS TAB, Model RTS-333-TAB