Method and apparatus for ensuring compatibility on a high performance serial bus

• US 20060072590A1
• Filed: 11/21/2005
• Published: 04/06/2006
• Est. Priority Date: 02/17/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Whitby-Strevens, Colin, Hauck, Jerrold V.
• Granted Patent: US 7,701,966 B2
• Time in Patent Office: Days
• US Class Current: 370/400
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 12/40052 High-speed IEEE 1394 serial bus bus transfer protocol on a daisy chain bus using an embedded synchronisation G06F13/426
• CPC Class Codes: H04L 12/40071 Packet processing; Packet format adaptation of digital video signals for transport over a specific network H04N21/2381, H04N21/4363, H04N21/4381; packet switches H04L49/00; intermediate storage or scheduling H04L49/90
• CPC Class Codes: H04L 12/6418 Hybrid transport

Abstract

A data communications system is disclosed having at least one Legacy cloud coupled to at least one Beta cloud. The system further having at least one BOSS node and at least one border node. A method for ensuring compatibility is disclosed comprising determining when the BOSS node is idle, determining whether the last packet transmitted by any border node was an Alpha format packet if the BOSS node is idle, and unlocking the Legacy cloud if the last packet transmitted by the border node was not an Alpha format packet.

Claims

1. A computer-readable medium containing instructions which, when executed by a computer, ensure compatibility in a data communications system between at least one Legacy cloud coupled to at least one Beta cloud and at least one BOSS node and at least one border node, by performing the acts of:

determining when said BOSS node is idle;

determining whether the last packet transmitted by any border node was an Alpha format packet if said BOSS node is idle; and

unlocking said Legacy cloud if the last packet transmitted by said border node was not an Alpha format packet.

2. A computer-readable medium containing instructions which, when executed by a computer, ensure compatibility in a data communications system between at least one Legacy cloud coupled to at least one Beta cloud and at least one border node receiving and transmitting packets, by performing the acts of:

determining whether the last packet transmitted or received by the border node was an Alpha format packet;

arbitrating for control of the bus if said last packet transmitted or received by the border node was not an Alpha format packet;

determining whether said border node'"'"'s arbitration request was granted;

repeating said last packet received if said arbitration request was not granted and returning back to the step of determining whether the last packet transmitted or received by the border node was an Alpha format packet; and

unlocking the Legacy cloud if said arbitration request was granted.

3. A computer-readable medium containing instructions which, when executed by a computer, ensures compatibility in a data communications system compliant with the P1394b standard and having at least one B PHY, by performing the acts of:

determining whether the B PHY desires to communicate at a speed on a bus having a peer device not capable of communicating at said speed; and

speed filtering said peer device if said B PHY determines that said peer device cannot communicate at said speed.