Method and apparatus for tdm interrupt transmissions between multiple

Abstract

Apparatus provides time division multiplex (TDM) transmissions of interrupt requests between a plurality of shelves to a microprocessor mounted on one of the shelves. The shelves are interconnected with a cable wherein one lead is dedicated for the transmission of interrupt data signals to the microprocessor. Each shelf includes a plurality of ports or elements that are monitored and initiate interrupt request signals when a request for an action occurs therein for processing by the microcomputer. A separate encoder is mounted on each of the shelves for converting an interrupt request signal from an element on the same shelf into an X-bit interrupt data signal identifying that element. The bits of the X-bit interrupt data signal are serially transmitted over the one lead of the cable during a separate plurality of at least X clock cycles forming a timeslot assigned to the shelf originating the interrupt request within a frame period. The encoder on the shelf with the microprocessor receives the X-bit interrupt data signal and generates a Y-bit signal including the received X-bit interrupt data and a Z-bit code identifying the shelf originating the X-bit interrupt data signal as determined from the timeslot in the frame period in which the X-bit interrupt data signal was received. This Y-bit signal is transmitted to the microprocessor for processing.