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Browse Prior Art Database

Dual Priority Bus Arbitration Unit

IP.com Disclosure Number: IPCOM000105396D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Hovatter, MJ: AUTHOR [+4]

Abstract

Disclosed is a method of arbitrating among N bus masters for the use of a common facility, where each potential master may have a high priority request or a lower priority request.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 63% of the total text.

Dual Priority Bus Arbitration Unit

      Disclosed is a method of arbitrating among N bus masters for
the use of a common facility, where each potential master may have a
high priority request or a lower priority request.

      The arbitrator considers both a high and a low priority bus
request at the same time from each requestor.  If any high priority
requests are present, they will be considered before any low priority
requests.  If they are absent then only the low priority requests are
used.  As shown in Fig. 1 each requestor has two bi-directional
interface lines to the arbitor.  One line (called Request low/Grant
high) is used to request a low priority bus operation or receive a
grant to a high priority re quest.  The other line (called Request
high/Grant low) is used to request a high priority bus operation or
receive a grant to a low priority request.  In other words, the
opposite line from the request is used to signal a grant from the
arbitor to the requestor.

      The advantage to this implementation is that only two signals
are required to request either type request and issue either grant
type, and this can be done in a minimum of time due to the lack of
collisions on these signals between a request and a grant, and
therefore no turn around time for removing a request and issuing a
grant need be specified.  A requestor may raise a request any time
and keep its request active until it is granted.

      At the start of a new arbitratio...