Integrated multi-port repeater having shared resources

Abstract

A discrete integrated repeater device and port MAU/AUI functions shares resources among its several ports. The device includes a single multi-bit free running counter providing preselected timing intervals to a plurality of latches. A signal undergoing measurement clears the latch while a preselected timing signal sets the latch. Receipt of a timing signal at a set latch indicates success or failure of some particular condition under test. The device satisfies an IEEE 802.3 specification for execution of a link integrity test. The device is also able to selectively disable or enable the link integrity test function for particular ports. A plurality of latches, one associated with each port, is set upon carrier sense detection at the particular port. A token passing mechanism implemented with a daisy chained line coupled to each latch enables a polling of each latch to provide carrier sense information about each port in a serial format. The device shares a single PLL among all its ports by producing a logical sum of carrier sense inputs to enable activation of the PLL. A collision indication signal will override operation of the PLL to ensure data integrity and to allow the PLL to reacquire lock on its reference clock.