Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ames!bionet!synoptics!unix!ginger.sri.com!henry
From: henry@ginger.sri.com (Henry Pasternack)
Newsgroups: comp.sys.m68k
Subject: Need help connecting m68k to a UNIX box.
Message-ID: <14703@unix.SRI.COM>
Date: 30 Jul 90 20:20:11 GMT
Sender: news@unix.SRI.COM
Reply-To: henry@ginger.sri.com (Henry Pasternack)
Organization: SRI International
Lines: 29


   This is technically a UNIX question, but I have this paranoid 
feeling that posting to a UNIX bulletin board would be an exercise
in futility.  Perhaps someone over here can help me out.

   Problem: My 68000 board is running now, and I'm successfully
programming it in C using the Sun3 compiler.  I've written a two-part
communications program for the purpose of downloading S-record code
from a SPARCStation to the 68000.  I use kermit to provide terminal
emulation over the Sun's 'ttya' port.  The 'ttyb' port is driven by
my communications program which listens for file requests from the 
client and dumps S-records on command.

   I'm having a lot of trouble getting the interface to '/dev/ttyb'
to work.  I admit to knowing virtually nothing about UNIX I/O, and
the reference manuals aren't much help.  The port already seems to be
configured for 9600 baud, which is convenient.  I do an 'fopen' on
'/dev/ttyb' and use 'gets' and 'fprintf' to perform I/O.  The Sun
has no problem receiving command lines from the client, but when the
client begins polling for a response after sending a request, it gets
a garbled copy of its request back.  It seems as though the buffer
UNIX is creating is bidirectional, rather than dual-unidirectional.

   Can anyone give me an understandable explanation of how to set
up my SPARCStation to do simple and effective I/O to the serial ports?

   Thanks.

-Henry