Synchronizing system using IEEE 1394 serial bus standard
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsSatoru Nakai, Kenji Suzuki, Shinichiro Chino, Yuusuke Ushio
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Abstract
Transmission delay in a serial bus connected network is determined by transmitting a Ping packet which is replied to in a physical layer of the bus from a request node to a response node, and measuring the time required from transmission of Ping packet by the request node until a Self—ID packet corresponding to the Ping packet is returned to the request node. The delay deviation between cycle timers of the request node and the response node is compensated by this transmission delay. The delay deviation may be also compensated using a time stamp.
Claims14
A synchronizing system using an IEEE1394 serial bus for synchronizing among nodes in a network connected by the IEEE1394 serial bus, said synchronizing system comprising:
- a cycle timer delay measuring unit which measures mutual delay deviation amount of each cycle timer of each node, wherein said cycle timer delay measuring unit
- transmits a Read packet from a request node to a response node,
- reads a cycle timer value of the response node, and,
- when the request node receives a ReadResponse packet including the cycle timer value being read, calculates the delay deviation amount based on the difference between the received cycle timer value and the cycle timer value of the request node;
- and
- a cycle timer delay correcting unit which corrects mutual delay deviation of each cycle timer based on the delay deviation amount measured by said cycle timer delay measuring unit.
A synchronizing system using an IEEE1394 serial bus for synchronizing among nodes in a network connected by the IEEE1394 serial bus, said svnchronizing system comprising:
- a cycle timer delay measuring unit which measures mutual delay deviation amount of each cycle timer of each node;
- a cycle timer delay correcting unit which corrects mutual delay deviation of each cycle timer based on the delay deviation amount measured by said cycle timer delay measuring unit;
- a cycle timer delay transmission unit which transmits the delay deviation amount;
- and
- a node having a cycle master and including a reference cycle timer for synchronism and including said cycle timer delay measuring unit and said cycle timer delay transmission unit, wherein
- a first node, other than said node having the cycle master, includes said cycle timer delay correcting unit, and
- said node having the cycle master transmits the delay deviation amount measured to said first node, or stores the delay deviation amount measured in a data table,
- said first node acquires the delay deviation amount measured from said node having the cycle master, and
- the delay deviation of the cycle timer is corrected based on the delay deviation amount transmitted to said first node or the delay deviation amount acquired.
A synchronizing system using an IEEE1394 serial bus for synchronizing among nodes in a network connected by the IEEE1394 serial bus, said synchronizing system comprising:
- a cycle timer delay measuring unit which measures mutual delay deviation amount of each cycle timer of each node;
- a cycle timer delay correcting unit which corrects mutual delay deviation of each cycle timer based on the delay deviation amount measured by said cycle timer delay measuring unit;
- a cycle timer delay transmission unit which transmits the delay deviation amount;
- and
- a node having a cycle master and including said cycle timer delay correcting unit, wherein
- a first node, other than said node having the cycle master, includes said cycle timer delay measuring unit and said cycle timer delay transmission unit, and
- a specified node transmits the delay deviation amount measured by said first node to said node having the cycle master, or acquires the delay deviation amount from said first node, and the delay deviation of the cycle master of said node having the cycle master is corrected based on the delay deviation amount later transmitted to said first node or the delay deviation amount acquired.
Dependencies are inferred from the claim text.