6 678 784

6,678,784 Title:

System and method for address broadcast synchronization using a plurality of switches

A system and method providing address broadcast synchronization using multiple switches. The system for concurrently providing addresses to a plurality of devices includes a first switch and a second switch. The first switch is coupled to receive address requests from a first plurality of sources. The first switch is configured to output the address request from the first plurality of sources. The second switch is coupled to receive address requests from a second plurality of sources. The second switch is configured to receive the address request from the first plurality of sources from the first switch. The second switch is further configured to delay the address request from the second plurality of sources prior to arbitrating between ones of the address request from the second plurality of sources and ones of the address request from the first party of sources received from the first switch. The second switch selects a selected address request, and the first and the second switch are further configured to broadcast concurrently a corresponding address to the selected address request. A method is also contemplated for concurrently providing addresses to a plurality of devices. A method of arbitrating in a first switch and a second switch between requests to the first switch and the second switch is disclosed where the arbitrated outcomes in both the first switch and the second switch are identical.

What is claimed is:

1. A method of arbitrating in a first switch and a second switch between requests to said fist switch and said second switch, the method comprising: tracking which switch wasmost recently selected; tracking which switch is next to be selected; in response to a reset, selecting the first switch; and indicating the second switch as next to be selected; in response to only a local request to said first switch or only aremote request to said second switch, selecting the first switch; and indicating the first switch as next to be selected; in response to only a local request to said second switch or only a remote request to said first switch, selecting the secondswitch; and indicating the second switch as next to be selected; in response to both a local request and a remote request concurrently, selecting a switch not most recently selected; and indicating the switch not most recently selected as next to beselected; otherwise, selecting the first switch; and indicating the switch most recently selected as next to be selected.

2. The method of claim 1, further comprising: indicating the switch next to be selected as the switch most recently selected upon a rising edge of a clock.

3. A method of arbitration between requests received by a first arbitration unit and a second arbitration unit, said method comprising: each of said first and said second arbitration units selecting for output a same one of said first and saidsecond requests dependent upon which of said first and said second requests has been received at said first and said second arbitration units; wherein each of said first and said second arbitration units: determining which of a fist request received bysaid first arbitration unit and a second request received by said second arbitration unit was most recently selected; selecting said first request in response to only receiving said first request and indicating that said first request is next to beselected; selecting said second request in response to only receiving said second request and indicating that said second request is next to be selected; selecting which of said first request and said second request that was not most recently selectedin response to receiving both of said first request and said second request concurrently and indicating that said not most recently selected request is next to be selected.

4. The method of claim 3 further comprising each of said first and said second arbitration units selecting said first request and indicating that said second request is next to be selected in response to a reset.

5. The method of claim 3 further comprising each of said first and said second arbitration units selecting a next request received by said first switch and indicating that the request most recently selected is next to be selected in response toreceiving neither of said first and said second requests.

6. A system comprising: a first switch configured to receive a first request, wherein said first switch includes a first arbitration unit; and a second switch configured to receive a second request wherein said second switch includes a secondarbitration unit; wherein said first switch and said second switch are coupled together, wherein said first request is routed to said second arbitration unit and said second request is routed to said first arbitration unit; wherein each of said firstand said second arbitration units is configured to: select said first request and to indicate that said second request is next to be selected in response to a reset; select said first request in response to only receiving said first request and toindicate that said first request is next to be selected; select said second request in response to only receiving said second request and to indicate that said second request is next to be selected; determine which of said first request and said secondrequest was most recently selected; and select which of said first request and said second request that was not most recently selected in response to receiving both of said first request and said second request concurrently and to indicate that said notmost recently selected request is next to be selected.

7. The system of claim 6, wherein each of said first and said second arbitration units is further configured to indicate the request next to be selected as the request most recently selected upon a rising edge of a clock.

8. The system of claim 6, wherein each of said first and said second arbitration units is further configured to select a next request received by said first switch and to indicate that the request most recently selected is next to be selected inresponse to receiving neither of said first and said second requests.