Method and apparatus for hot swapping and bus extension without data corruption
AssigneeHewlett-Packard Company
InventorsMichael John Erickson, Daniel V. Zilavy
Life of this patent
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Abstract
A method and apparatus for hot swapping and bus extension without data corruption. During the hot swapping of a circuit board in a bus, the bus is extended onto or retracted from the circuit board in a manner which does not corrupt the data on the bus. The extension or retraction of the bus is detected and a bus reset is asserted interrupting and preventing transactions on the bus. The bus reset is asserted for a minimum amount of time to allow the bus to stabilize after the hot swap. A bus extension/retraction detection component and a bus reset component perform these functions.
Claims26
A method for extending or retracting a bus without data corruption, comprising:
- detecting a bus extension or retraction, wherein the bus extension or retraction indicates that a hot swap is taking place;
- asserting a bus reset, in response to the detection of the bus extension or retraction, wherein the asserted bus reset clears the bus of all active transactions;
- deactivating a first bus terminator, wherein the bus does not terminate at the deactivated first bus terminator;
- activating a second bus terminator, allowing the bus to be stably extended or retracted, wherein the bus does terminate at the activated second bus terminator;
- and
- de-asserting the bus reset, wherein the bus reset is asserted a minimum amount of time to allow the bus to stabilize and transactions interrupted by the bus reset can be reinitiated and resumed.
An apparatus for extending or retracting a bus without data corruption, comprising:
- a detection component, wherein the detection component receives at least one input and determines when the bus is being extended or retracted from the at least one input;
- and
- a bus reset assertion component, that receives a signal from the detection component, wherein the bus reset assertion component asserts a bus reset when the detection component determines that the bus is being extended or retracted and de-asserts the bus reset after a minimum amount of time to allow the bus to stabilize, wherein the detection component and the bus reset assertion component are located on controller boards in a multi-controller enclosure, wherein the controller boards monitor each other for hot-swapping.
Dependencies are inferred from the claim text.