Method and apparatus for TDM interrupt transmissions between multiple devices and a processor

Apparatus for providing time division multiplex (TDM) transmissions of interrupt requests comprising:

• a plurality of M shelves, where M is an integer greater than 1, coupled in parallel by a cable of which one lead is dedicated for the transmission of interrupt data signals to each of the other shelves, each shelf comprising:
• a plurality of elements that are each monitored and transmit an interrupt request signal in response to a need for an action therein;
• and
• an encoder comprising a plurality of parallel terminals and a serial terminal that is coupled to the one lead of the cable, the encoder is adapted for receiving and converting each interrupt request signal received from the plurality of elements into an X-bit encoded interrupt data signal that identifies the element on the shelf requesting the interrupt, and for selectively transmitting the X-bit interrupt data signal over the one lead of the cable in a timeslot within a frame period that is dedicated to the shelf, where each timeslot comprises X clock cycles and each bit of the X-bit encoded interrupt data signal is serially transmitted over the one lead of the cable during a separate one of the X clock cycle of a timeslot during a frame period assigned to each shelf, where X is an integer greater than 1;
• and
• a microprocessor mounted on a predetermined one of the plurality of shelves for processing a Y-bit interrupt data signal which is transmitted to the microprocessor in parallel from the encoder located on the predetermined one of the plurality of shelves, the Y-bit signal comprising the X-bit encoded interrupt data signal identifying the element on a shelf requesting an interrupt and a Z-bit code identifying the shelf from which the X-bit encoded interrupt data signal originated as determined from the timeslot in which the X-bit interrupt data signal is received, where Z is an integer equal to or greater than 1, and Y is an integer equal to or greater than X+Z.

A method of providing time division multiplex (TDM) transmissions of interrupt requests comprising the steps of:

• (a) coupling a plurality of M shelves, where M is an integer greater than 1, to a cable wherein one lead thereof is dedicated for the transmission of interrupt data signals to all of the other shelves;
• (b) transmitting an interrupt request signal from an element on any one of the plurality of M shelves to an encoding means mounted on that same shelf in response to a request for action in the element;
• (c) converting the interrupt request signal received in the encoding means in step (b) into an X-bit encoded interrupt data signal which uniquely identifies the element on the shelf initiating the interrupt request, where X is an integer greater than 1;
• (d) selectively transmitting the X-bit encoded interrupt data signal generated in step (c) over the one lead of the cable to all of the other shelves during a predetermined timeslot within a frame period that is dedicated to the shelf, where each timeslot comprises X clock cycles and each bit of the X-bit encoded interrupt data signal is serially transmitted during a separate one of the X clock cycles in the timeslot assigned to the shelf;
• and
• (e) receiving the X-bit encoded interrupt data signal transmitted in step (d) in an encoding means mounted on a predetermined one of the plurality of shelves and generating a Y-bit signal that is transmitted to a microprocessor mounted on the predetermined one of the plurality of shelves comprising the received X-bit encoded interrupt data signal and a Z-bit code identifying the shelf from which the X-bit encoded interrupt data signal originated, where Z is an integer equal to or greater than 1, and Y is an integer equal to or greater than X+Z.