Memory arbitration scheme with circular sequence register
AssigneeLSI Logic Corporation
InventorsPeter Bell, John Massingham, Alex Darnes
Life of this patent
Estimating the term…
Abstract
Apparatus for arbitrating between requests from a plurality of sources for access to a shared resource, the apparatus comprising: a register means having a plurality of stages, each stage containing a designation of one of said sources, a plurality of stages containing a designation of the same source, logic means for accessing the register stages according to a priority scheme and for comparing the designation in each stage with requests for access, and granting access according to the match between the highest priority source designation and a memory request, and means for changing the contents of the register means subsequent to access grant.
Claims8
Apparatus for arbitrating between requests for access to a shared resource, the apparatus comprising:
- a plurality of request inputs, wherein each request input comprises a source designation and indicates whether that source is requesting access to the shared resource;
- a circular sequence register having a plurality of successive stages with respective, successively decreasing priorities, wherein each source designation is stored in a selected number of the stages that is based on a relative access bandwidth requirement for that source;
- logic means for comparing the source designations stored in the successive stages with the plurality of request inputs to identify a set of the stages that store designations of sources that are requesting access and for granting access to the source designation that is stored in the highest priority stage within the set;
- and
- shifting means for shifting all of the source designations in a common direction within the sequence register after the logic means grants access.
A method for arbitrating between requests for access to a shared resource, comprising:
- receiving a plurality of request inputs, wherein each request input comprises a source designation and indicates whether that source is requesting access to the shared resource;
- providing a circular sequence register having a plurality of successive stages with respective, successively decreasing priorities;
- storing each source designation in a selected number of the stages that is based on a relative access bandwidth requirement for that source;
- comparing the source designations stored in the successive stages with the plurality of request inputs to identify a set of the stages that store designations of sources that are requesting access and for granting access to the source designation that is stored in the highest priority stage within the set;
- and
- shifting all of the source designations in a common direction within the sequence register after the granting access.
Dependencies are inferred from the claim text.