| 摘要 |
A protocol and associated addressable shadow port circuitry for efficiently extending serial bus capability to the backplane environment is disclosed. The protocol is designed to co-exist and be fully compatible with existing serial bus approaches. Circuitry and a protocol operable to couple any one of the boards (BOARD1-BOARDN) on the system backplane bus to the serial bus master (SBM) is described, wherein the protocol operates to select and deselect the boards without interfering with the normal operations on the system backplane bus. The protocol and circuitry is extended to hierarchically arranged systems, so that a primary serial bus master (SBM) device can selectively access and communicate with any device positioned at any level of the hierarchy. Further disclosed embodiments utilize multiple remote serial bus masters on hierarchically arranged networks, each remote serial bus master being coupled to a primary serial bus master using the protocol and circuitry of the invention, so that autonomous testing may be performed by the remote serial bus master devices under the control of the primary serial bus master. |
