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Article View: comp.sys.transputer
Article #1792

Problems with c004 Linkswitch

#1792
From: Stephan Wenger
Date: Wed, 29 May 1991 09:32
32 lines
1982 bytes
Hello,
this is my first posting to the net, so please be patient about the
"netiquette" and my English.
I have a hardware (?) problem concerning the c004 Linkswitch. I have
build a wrapped prototype board with one T800 and one c004. The
links 0..31 of the c004 are connected via a backplane to 8 T800
which will do the work I need. All links are bufferd by 74AC244 and
have matching 75 Ohm resistors on the transmitter and 1 kO pulldowns
at the receiver. The longests connection on the (wrapped) backplane
is about 20 cm. The link 31 of the c004 is connected to the link 2
of the T800 on this board to allow network-loading.
I use the tds2 (D700c) Network-Tester after programming and verifying
the c004. Even if only two links are connected, i get "Link Error 17"
and sometimes various token errors. 
I have tried to wrap a quick hack, which plugs into the backplane
instead of the prototype-board, and everything works fine.
All the signals look fine (nearly no undershoot etc.) and VCC, GND
and decoupling is also ok.

My questions:

1. Has anybody out there solved a similar problem? Hints are welcome.
2. My application-SW (very low Link-Traffic) seems to work fine. Maybe
   I have a software-problem. Is it possible, that the searching-worm
   of the network-tester disconnect links, resets the link-switch,
   or something else?

Replies per email please. I will post a summary if requested.

Yours Stephan Wenger

stewe@opal   stewe@tub
Technical Details
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!sdd.hp.com!cs.utexas.edu!uunet!math.fu-berlin.de!opal!stewe
From: stewe@opal.cs.tu-berlin.de (Stephan Wenger)
Newsgroups: comp.sys.transputer
Subject: Problems with c004 Linkswitch
Summary: C004, LinkError 17
Keywords: C004
Message-ID: <3513@kraftbus.cs.tu-berlin.de>
Date: 29 May 91 09:32:29 GMT
Sender: stewe@opal.cs.tu-berlin.de
Followup-To: comp.sys.transputer
Organization: Technical University of Berlin, Germany
Lines: 32