Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: 3M Laser Imager
Message-ID: <13150@mimsy.UUCP>
Date: 23 Aug 88 13:47:02 GMT
References: <978@godot.radonc.unc.edu>
Distribution: na
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 29

In article <978@godot.radonc.unc.edu> thorn@godot.radonc.unc.edu
(Jesse Thorn) writes:
>(running either BSD 4.3 or Ultix 2.0-1). ...
>The LI ... [requires] 8 data bits + 2 stop bits with even parity.
>... The problem is getting UNIX to configure the tty line this
>way - I just can't seem to get an 8 data bit/even parity setup.

You are correct: you cannot get 8 data bits plus parity (for a
total of 9 bits) out of either 4.3BSD or Ultrix 2.0-1.  The serial
port hardware is capable of this, but the system has no means to
set it.

>... I have grovelled through the source
>code of the UNIX tty and don't see why this setup won't work.

Whatever parity you set, it subsumes the eigth bit.  If you set
PASS8 mode (available in 4.3BSD, at least) the eight bit will
not be forced to even or odd parity, but the serial port itself
will then be set to eight data bits, no parity bits; even at two
stop bits, you will still only get ten data bits per character.

Since you have source code, you can fix this.  You will have to
add a flag (somewhere; in 4.3BSD, there is one bit left in t_flags,
defined as `L001000') just for this mode, or else rewire much of
the existing code (which needs doing, and has needed doing for
quite some time now).
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris