Cypress Semiconductor Corporation

Michael K Laudon

David S Wong

A communication unit, coupled to a communication link, may be enabled if a signal is present on the communication link and the unit is active. However, if no signal is present on the communication link, the communication unit generates a token used to activate another communication unit coupled to another communication link. This token may be generated after a delay which allows the communication unit to wait some time for the signal to appear on the communication link before generating the token. Where a communication unit has been activated and enabled, that communication unit may receive signals from the communication link or transmit signals onto the communication link. Selecting a first communication unit from a number of communication units to be activated may be accomplished by coupling one of the communication units to a start-up circuit. The start-up circuit provides a start-up token to activate the first communication unit.

Circuit, architecture and method for redundant data communications links

A multi-port network interface device including a transmit data bus; a receive data bus; a medium access controller (MAC) and physical signaling (PLS) circuit, coupled to the transmit and receive data buses, and configured to interface to a network layer; at least one transmitter, coupled to the transmit data bus, and configured to transmit data to a physical layer; at least one receiver, coupled to the receive data bus, and configured to receive data from the physical layer; a local collision detector, coupled to the transmit and receive data buses, and configured to detect local collisions on the physical layer; a near end collision detector, coupled to the receive data bus, and configured to detect near end collisions on the physical layer; and a jabber detector, coupled to the transmit data bus, and configured to monitor a length of data transmissions. The at least one receiver is configured to place data, received from the physical layer, on the receive data bus for transmission to the network layer by the MAC and PLS circuit; and the MAC and PLS circuit is configured to place data, received from the network layer, on the transmit data bus for transmission to the physical layer by the at least one transmitter.

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Monte Sereno, CA, United States of America

Michael K Laudon