Hewlett-packard Development Company, L.p.

Mike J Erickson

David R Maciorowski

Paul John Mantey

A method for restoring stability to an unstable bus includes cycling a clock of the bus a number of times, transmitting a stop bit, cycling a clock line of the bus at least one time and transmitting a stop bit immediately after an acknowledgment bit has been received by a bus master.

Restoring stability to an unstable bus

Disclosed are systems and methods for providing access to bus-mastered system resources comprising disposing a bus multiplexer between a first bus and a bus access arbiter, wherein the first bus is coupled to at least one system resource for which bus access is arbitrated by the bus access arbiter, and controlling the bus multiplexer to couple a second bus to the first bus thereby providing a link between the first bus and the second bus bypassing the bus access arbiter.

Systems and methods for accessing bus-mastered system resources

A system, such as a complex computer system, incorporates several programmable logic devices coupled to load their configuration code from associated EEPROMs; typically this load is automatic on powerup. The EEPROMs connect to one of several serial busses, typically JTAG busses, connecting the EEPROMs with a common configuration logic. A processor is configured to write programmable logic configuration code from its memory through the common configuration logic and over the serial busses into the EEPROMs. The processor is also capable of connecting to a network and fetching configuration code for writing to the EEPROMs.

System and method for in-system programming through an on-system JTAG bridge of programmable logic devices on multiple circuit boards of a system

A field unit has a connector with first and second interconnect apparatus coupled to connector. The field replaceable unit has test apparatus coupled to the first and second interconnect apparatus capable of testing connections through the connector to the first interconnect apparatus under control of signals on the second interconnect apparatus. The field replaceable unit is capable of being hot-plugged. In an embodiment, the second interconnect apparatus is of the JTAG type. Also claimed is a method of testing interconnect between the field replaceable unit and another unit of a system into which it has been hot-plugged.

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Loveland, CO, United States of America

Mike J Erickson