Patent Number: 6,490,641

Title: Addressable shadow port circuit

Abstract: A protocol and associated circuitry operable for efficiently extending serial bus capability in system environments is disclosed. The protocol is designed to coexist and be fully compatible with existing serial bus approaches, and in particular an example of application of the invention to a backplane system utilizing the 1149.1 IEEE standard serial bus is detailed. The circuitry and protocol required to couple any one of the boards on the backplane to the serial bus master without modifying the existing serial bus protocol, without adding additional signals, and without affecting the throughput rate of the serial bus is described. The invention advantageously allows the serial bus master to select, communicate with, and deselect backplane boards so that high level test functions may be simultaneously executed and monitored. Additional preferred embodiments are also disclosed.

Inventors: Whetsel; Lee D. (Plano, TX)

Assignee: Texas Instruments Incorporated

International Classification: G06F 11/00 (20060101); G06F 13/00 (20060101); G06F 013/00 (); G06F 011/00 ()

Expiration Date: 12/03/2019