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From: hyc@hanauma.jpl.nasa.gov (Howard Chu)
Newsgroups: comp.sys.atari.st
Subject: Re: TT REVIEW
Message-ID: <1991Mar23.014107.1300@jato.jpl.nasa.gov>
Date: 23 Mar 91 01:41:07 GMT
References: <1991Mar20.141344.6808@newcastle.ac.uk> <1565@aupair.cs.athabascau.ca>
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In article <1565@aupair.cs.athabascau.ca> rwa@cs.athabascau.ca (Ross Alexander) writes:
>About the serial ports: how many _uarts_ does this machine have, as
>opposed to how many connectors appear on the back?  Is it one-to-one,
>or do perhaps some connectors share a single uart?  Also, could some
>well informed reader tell me (us) what the uart types for the various
>ports are (6850, 8350, 8250, 16650a or what have you)?

5 ports, 4 UARTs. Two are 68901, two are Zilog 8530. One of the 8530s
is connected to both a serial port and the "LAN" port, configurable for
Localtalk speed (230kbps). Two 68901s are used in the TT as opposed to
the single 68901 in STs. I guess they needed another to handle interrupt
vectoring for all the new devices...
(Oops. Is it really 8350? Whatever. The Zilog chip, same one as used in
Mac and Sun.)
>
>I ask this since I understand that the Mega STe shares a uart between
>the LAN port and one of the rs232 ports (implying that you can't
>simultaneously converse with both the LAN and a device on the rs232
>port in question).  I may be wrong (I hope I am wrong), but I suspect
>there's an element of `checklist engineering' here.

Correct.
-- 
  -- Howard Chu @ Jet Propulsion Laboratory, Pasadena, CA
	Disclaimer: How would I know, I just got here!