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Determining Bus Drive Direction of a Transceiver Circuit in a High-Speed Digital System

IP.com Disclosure Number: IPCOM000042956D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Farn, B: AUTHOR [+3]

Abstract

This article describes a transceiver circuit used to control transceiver drivers in a high-speed digital computer system. The circuit shown in the figure has been divided into three sections. Section 1, the top one-third of the diagram, shows two back-to-back drivers arranged in a transceiver configuration used to receive and redrive a computer's digital data bus. Of interest is the bottom two-thirds of the diagram (sections 2 and 3) which provide the control for these drivers. The circuit shown in section 2 is identical to that in section 3. These two fully symmetrical circuits are connected in a transceiver configuration. This allows the incoming Data Bus Direction Control signal, which determines bus drive direction for the section 1 drivers, to be propagated to other cards in the system.

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Determining Bus Drive Direction of a Transceiver Circuit in a High-Speed Digital System

This article describes a transceiver circuit used to control transceiver drivers in a high-speed digital computer system. The circuit shown in the figure has been divided into three sections. Section 1, the top one-third of the diagram, shows two back-to-back drivers arranged in a transceiver configuration used to receive and redrive a computer's digital data bus. Of interest is the bottom two-thirds of the diagram (sections 2 and 3) which provide the control for these drivers. The circuit shown in section 2 is identical to that in section 3. These two fully symmetrical circuits are connected in a transceiver configuration. This allows the incoming Data Bus Direction Control signal, which determines bus drive direction for the section 1 drivers, to be propagated to other cards in the system. The architecture of the circuit monitors both control signals, the Data Bus Direction Control signal (bottom) and Data Bus Direction Control signal (top) to determine the direction of the data flow. The control line to go active first will determine the direction of the data bus through this card, i.e., whether to drive the bottom connector tab pin signals to the top connector tab pin signals, or vice-versa. The two control signals are normally at a logic '1' or 'off' state. To understand the circuit flow, consider the following example where the data bus will be driven from card bottom to card top. When the Data Bus Direction Control signal from the bottom turns on, going from positive to negative, the section 2 circuit takes over. This allows the logic to propagate the control signal to the top connector of the card, where it be...