Newsgroups: comp.robotics
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From: strohm@mksol.dseg.ti.com (john r strohm)
Subject: Re: Help Please : Pan-Tilt Unit Model PTU from Directed Perception
Message-ID: <1993Nov15.162949.26868@mksol.dseg.ti.com>
Keywords: Pan-Tilt Unit
Organization: Texas Instruments, Inc
References: <2c15i5$9s@wraith.cs.uow.edu.au>
Date: Mon, 15 Nov 1993 16:29:49 GMT
Lines: 34

In article <2c15i5$9s@wraith.cs.uow.edu.au> g8615851@wraith.cs.uow.edu.au (Neil Lindsay Harper) writes:
>Hi,
>
>I am doing a project for my MCompSci project writing control software
>on a Macintosh.
>
>I am trying to use a Computer Controlled PAN-TILT UNIT model PTU
>from Directed Perception and I have no problems communicating
>with it using a simple terminal emulator on the Macintosh.
>
>I am using the macintosh toolbox for my read and writes to the
>serial links namely FSREAD and FSWRITE and the very first
>FSWRITE that I do just hangs up completely.

This SMELLS like an interrupt enable/interrupt handler initialization
problem.  If your FSWRITE driver is interrupt-driven, and you wait for
it to complete, and it never gets the interrupt back, you can expect to
wait for a long time.

>
>Note : If I have the terminal emulator open in the background with
>multifinder then I  my software can read and write to the controller
>without any problems.

Yup.  The terminal emulator probably enables the interrupt.

>
>Any suggestions would be appreciated.
>
>Thanks
>Neil Harper
>Wollongong, Australia


