Browse Prior Art Database

Data Control Shift Register

IP.com Disclosure Number: IPCOM000096458D
Original Publication Date: 1963-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Heilwell, MF: AUTHOR

Abstract

In a DC shift register employing two gated latches for each register position, the possibility exists, when entering data into the first latch in response to a rise of the gate input, that the gate of the second latch will not close before the data in the first latch changes. This shift register eliminates this possibility. It closes the second gate in response to a change of data rather than in response to a rise of the gate input.

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Data Control Shift Register

In a DC shift register employing two gated latches for each register position, the possibility exists, when entering data into the first latch in response to a rise of the gate input, that the gate of the second latch will not close before the data in the first latch changes. This shift register eliminates this possibility. It closes the second gate in response to a change of data rather than in response to a rise of the gate input.

The shift register has sequentially connected, gated latches 1 and 2. The data and gate inputs are supplied directly to latch 1. The gate input is also inverted by 11 and applied to latch 2. Thus, when the gate input is at an up level, the gate of the first latch is open and the gate of the second latch is closed. When the gate input is at a down level, the gate of the first latch is closed and the gate of the second latch responds to the output of an Exclusive-Or circuit. This responds to a change in the data input from the data stored in latch 1 to provide an output which is inverted by 12.

The gate of latch 2, therefore, responds to a change in the data input to close prior to the time that the gate line is changed. In doing this, the gate of latch 2 is closed before the gate to latch 1 is opened to prevent the data passing from latch 1 to latch 2.

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