Method for pre-processing data packets

US6622187B1 · kind B1 · utility

Assignee

• Thomson Licensing · FR

Inventors

• Thomas Brune · Hannover, DE
• Ralf Ostermann · Hannover, DE
• Jens Cahnbley · Lüneburg, DE
• Siegfried Schweidler · Gehrden, DE

Key dates

• Filing date: May 30, 2000
• Grant date: Sep 16, 2003
• Expiry date: Jul 19, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L69/22
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

The IEEE1394 bus communication protocol has three layers: physical layer, link layer, and transaction layer. A link layer IC implements the interface to an external application and prepares data for sending on the bus, or interprets incoming data packets from the IEEE1394 bus. A physical layer IC implements the direct electrical connection to the bus and controls many functions including arbitration for sending data on the bus. A problem exists due to the fact that the header data of the IEEE1394 asynchronous data packets consists of 32 bit words which have to be interpreted as 32 bit words in the connected application data processing unit (30). The IEEE1394 bus interface unit (20) is defined to be of big endian type. In a little endian type application data processor (30) the data word order can only be correctly interpreted after a byte order change. According to the invention the byte order change is performed in the data link layer unit (21) automatically with hardware circuitry for asynchronous data packets.