LAN switch interface for providing arbitration between different simultaneous memory access requests

摘要

A plural interface LAN switch arbitration method dividing access to a packet memory into a plurality of sequential cycles. A refresher is provided for refreshing the packet memory and the refresher issues a refresher request when the refresher needs to access the packet memory. A first and second interface are provided for transferring data between the packet memory and the respective first and second LAN's. The first and second interface issue a respective first and second interface request when the respective interface needs to access the packet memory. A processor is provided for updating the packet memory and issues a processor request when the processor needs to access the packet memory. The arbitration provides the refresher with an immediately next cycle of the memory when the refresher request is present. The arbitration method also provides the processor with an immediately next cycle of the packet memory when the processor request is present and the refresher has a present cycle which guarantees the processor periodic access to the memory.