Method and apparatus for using a bus as a data storage node
AssigneeAgere Systems Inc.
InventorsHyun Lee, David W. Potter, Lai Q. Pham
Life of this patent
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Abstract
The present invention is a method and apparatus for dynamically holding valid data logic levels on a bus by taking advantage of the inherent storage capacity of the bus. The bus speed is increased by eliminating the use of active bus keepers and null cycles. Instead, a two phase clock is used, the bus drivers drive data onto the bus during the first phase of the clock and are turned off at the beginning of the second phase of the bus clock. The receiving device latches the data during the second phase of the bus clock. Accordingly, there is no need for a null cycle or a bus keeper circuit, yet there is no bus contention between consecutive drivers nor is there a floating node condition.
Claims15
A method of transferring data over a bus between a transmitting device and a receiving device, said method comprising the steps of:
- (1) turning said transmitting device on to drive data onto said bus by asserting an enable signal that controls a driver of said transmitting device;
- (2) turning said transmitting device off by de-asserting said enable signal;
- and
- (3) latching said data at said receiving device after said enable signal is de-asserted;
- wherein no buskeeper is employed.
A method of transferring data over a bus between a transmitting device and a receiving device, said method comprising the steps of:
- (1) docking said bus with a clock having a clock cycle comprising at least a first phase and a second phase;
- (2) turning said transmitting device on to drive data on said bus by asserting an enable signal that controls a driver of said transmitting device;
- and
- (3) turning said transmitting device off by de-asserting said enable signal before said receiving device latches said data;
- wherein no buskeeper is employed.
Dependencies are inferred from the claim text.