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Path: utzoo!linus!philabs!prls!amdimage!amdcad!cae780!weitek!fear!robert
From: robert@fear.UUCP (Robert Plamondon)
Newsgroups: net.micro.trs-80,net.micro.pc
Subject: Serial Port woes on Tandy 2000
Message-ID: <244@fear.UUCP>
Date: Tue, 20-Aug-85 17:17:56 EDT
Article-I.D.: fear.244
Posted: Tue Aug 20 17:17:56 1985
Date-Received: Fri, 23-Aug-85 07:52:23 EDT
Organization: Weitek Corp. Sunnyvale Ca.
Lines: 39
Keywords: Tandy 2000 AUX Serial
Xref: linus net.micro.trs-80:272 net.micro.pc:4751

I've been trying to get some home-made communications routines to run
on my Tandy 2000, and have been having trouble at 1200 baud.
Irritatingly, everything works fine at 300 baud -- it just takes four
times as long.

What I'm trying to do is upload to a BBS system that always echoes
characters back (full duplex).  I'm waiting for the linefeed to be
echoed after every line before sending the next one, but I'm not
waiting for each character because of the large delays involved with
echoes coming back over long-distance services (yes, the BBS I work
with is long distance).

I use the BIOS calls to check the serial port status.  If there's a
received character, I get it and put it on the screen as my highest
priority.  If the status indicates that I can send a character, and
there's no received character to process, I send a character.

The Problem is that even though the status routine indicates that the
port is ready for a character, I will sometimes get a timeout error
anyway. Once a timeout error is received, I have to reinitialize the
port before being able to transmit again.

This can be avoided by putting in delay loops to the point of slowing
down to an effective baud rate of about 300 baud, but what's the
point of that?

So, if anyone can help me, I'd like:

1. A fix to the problem!

2. BIOS listings (are they available from Tandy?).



		-- 


		Robert Plamondon
		{turtlevax, resonex, cae780}!weitek!robert