Data processing apparatus having a flow control function for multi-cast transfer
First Claim
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1. A data processing apparatus comprising:
- a bus for which a band-guaranteed cycle capable of transferring stream data in real time by assigning a predetermined reserved band for each cycle time, is defined, the bus including a signal line which indicates a completion of a current data transfer cycle on the bus;
a plurality of nodes connected to said bus and capable of transmitting/receiving stream data using the band-guaranteed cycle, the plurality nodes being connected to the signal line in a wired OR fashion; and
means for executing a multi-cast transfer of stream data from a sender node to a plurality of receiver nodes using the band-guaranteed cycle, the sender node including a unit configured to stop the multi-cast transfer when the signal line is driven into an active state.
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Abstract
Two transfer modes of a band-guaranteed cycle and an event-driven type asynchronous cycle are defined for a multimedia bus. In the band-guaranteed cycle, stream data is transferred between nodes, to which the same channel number is assigned, in peer-to-peer mode using a reserved band for each cycle time. If the same channel number is assigned to a plurality of receiver nodes, a multi-cast transfer can be achieved by the band-guaranteed cycle. The multi-cast transfer using the band-guaranteed cycle can be stopped even in response to an instruction from any receiver node, and a buffer of each receiver node can be prevented from overflowing.
25 Citations
6 Claims
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1. A data processing apparatus comprising:
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a bus for which a band-guaranteed cycle capable of transferring stream data in real time by assigning a predetermined reserved band for each cycle time, is defined, the bus including a signal line which indicates a completion of a current data transfer cycle on the bus;
a plurality of nodes connected to said bus and capable of transmitting/receiving stream data using the band-guaranteed cycle, the plurality nodes being connected to the signal line in a wired OR fashion; and
means for executing a multi-cast transfer of stream data from a sender node to a plurality of receiver nodes using the band-guaranteed cycle, the sender node including a unit configured to stop the multi-cast transfer when the signal line is driven into an active state. - View Dependent Claims (2, 3, 4, 5)
drive means for driving the signal line into the active state for a predetermined time period when an amount of data stored in a receiving buffer for receiving stream data transferred by the multi-cast transfer, exceeds a given value, and driving the signal line into an inactive state after the predetermined time period has elapsed; and
means for monitoring a state of the signal line and inhibiting the drive means from driving the signal line when detecting that the signal line is driven into the active state by another node.
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6. A data processing apparatus comprising:
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a bus for which a band-guaranteed cycle capable of transferring stream data in real time by assigning a predetermined reserved band for each cycle time, is defined, the bus including a signal line which indicates a completion of a current data transfer cycle on the bus;
a plurality of nodes connected to said bus and capable of transmitting/receiving stream data using the band-guaranteed cycle, the plurality of nodes being connected to the signal line in a wired OR fashion; and
means for executing a multi-cast transfer of the stream data from a sender node to a plurality of receiver nodes using the band-guaranteed cycle by assigning one of plurality of channel number to the sender node and the plurality of receiver nodes, the sender node including a unit configured to stop the multi-cast transfer when the signal line is driven into an active state, wherein each of the plurality of nodes includes;
drive means for driving the signal line into the active state for a predetermined time period when an amount of data stored in a receiving buffer for receiving stream data transferred by the multi-cast transfer, exceeds a given value, and driving the signal line in an inactive state after the predetermined time period has elapsed; and
means for monitoring a state of the signal line and inhibiting the drive means from driving the signal line when detecting that the signal line is driven into the active state by another node.
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Specification