Browse Prior Art Database

INTEGRATED PASS-THROUGH LOGIC

IP.com Disclosure Number: IPCOM000005441D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2001-Oct-10
Document File: 1 page(s) / 45K

Publishing Venue

Motorola

Related People

Terry Lawell: AUTHOR

Abstract

In typical data communication systems configured in a ring or loop network, when an individual sta- tion loses power, the entire link goes down unless a mechanical relay is included to pass through data transmitted from the uplink station to the downlink station. However, the relay requires significant power and, when power is lost in high speed links, many data frames may be destroyed before the relay con- tacts settle down.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

INTEGRATED PASS-THROUGH LOGIC

By Terry Lawell

   In typical data communication systems configured in a ring or loop network, when an individual sta- tion loses power, the entire link goes down unless a mechanical relay is included to pass through data transmitted from the uplink station to the downlink station. However, the relay requires significant power and, when power is lost in high speed links, many data frames may be destroyed before the relay con- tacts settle down.

To perform the "pass through" function in a monolythic integrated circuit data link COntrOller, a separate XPWR pin is proposed to provide power independent of Vdd to the following circuitry:

EXT OV=NON-LOOP PWR +SV=LOOP

4 I 1

OFF LINE

   Since typical controllers are capable of operating in modes other than the loop configuration, the XPWR pin is also utilized to select loop mode, eliminating the normal requirement for a separate control register bit which must be loaded under software control. Thus, for example, if power is applied to the XPWR pin, loop mode is enabled and the "pass through" logic becomes functional upon loss of Vdd power. On the other hand, if the XPWR pin is grounded, the controller will operate in a non-loop mode and, upon loss of Vdd power, the "pass through" logic will also power down.

0 Motorola, Inc. 1982 15

[This page contains 15 pictures or other non-text objects]