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Round Robin Selection Device Using a Feedback Priority Encoder

IP.com Disclosure Number: IPCOM000061593D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Sibbers, DE: AUTHOR

Abstract

The use of a priority encoder in conjunction with feedback to inhibit previously serviced inputs enhances the speed and simplifies the implementation of a round robin selection device. It is desired to select for servicing one of a possible plurality of service requests S(O) - S(N) at the input and have the single request selected to appear in encoded form at output 5. Further, the selections of the service requests must be made in a round robin order. The highest-order service request in this instance is denoted as S(O), and the lowest-order service request is denoted as S(N). The basic sequence of operation following the first selection is as follows: 1. Encode Register 10 holds the encode of the last request serviced. 2.

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Round Robin Selection Device Using a Feedback Priority Encoder

The use of a priority encoder in conjunction with feedback to inhibit previously serviced inputs enhances the speed and simplifies the implementation of a round robin selection device. It is desired to select for servicing one of a possible plurality of service requests S(O) - S(N) at the input and have the single request selected to appear in encoded form at output 5. Further, the selections of the service requests must be made in a round robin order. The highest-order service request in this instance is denoted as S(O), and the lowest-order service request is denoted as S(N). The basic sequence of operation following the first selection is as follows: 1. Encode Register 10 holds the encode of the last request serviced. 2. The output of Encode Register 10 is fed back to gating logic 7 which inhibits the selected service request and all service requests of higher order. 3. The output of gating logic 7 is monitored by OR circuit 11 to determine if service requests of lower order need servicing. If not, the round robin is finished. 4. If the round robin is not finished, priority encoder 9 provides the encoded output of the highest-order service request of those remaining in the round robin. 5. A pulse is supplied to the select request input 3 to latch the output of priority encoder 9 into encode register 10 to supply the new output. It is important that encode register 10 be either edge triggered or of...