(54) SPURIOUS SIGNAL DETECTION
(75) Inventors: Simon Andrew Ford, Cambridge (GB);
David Michael Bull, Cambridge (GB);
Alastair David Reid, Cambridge (GB)
(73) Assignee: ARM Limited, Cambridge (GB)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 9 days.
(21) Appl.No.: 11/898,923
(22) Filed: Sep. 17, 2007
(65) Prior Publication Data
US 2008/0097713 Al Apr. 24, 2008
(30) Foreign Application Priority Data
Oct. 23, 2006 (GB) 0621056.1
(51) Int. CI.
G01R 29/02 (2006.01)
G01R 25/00 (2006.01)
(52) U.S. CI 702/79; 702/58; 702/117;
714/30; 714/55; 714/819
(58) Field of Classification Search 702/58,
702/79,117; 714/30,55,708,819; 331/105 See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
3,699,554 A * 10/1972 Jones 360/43
A circuit for a data processing apparatus and a method for detecting spurious signals is disclosed, the circuit comprising a data input operable to receive digital signal values, spurious signal detection logic operable to monitor a digital signal value within the circuit, and to determine at least one of: a safe time window during which it is expected that the digital signal values input into the circuit may cause data transitions in the monitored digital signal value and a transition time window in which it is expected a data transition will occur; and in response to detecting either a data transition in the monitored digital signal value outside of the at least one safe time window or no data transition in the transition window, the spurious signal detection logic is operable to output a detection signal.
20 Claims, 9 Drawing Sheets
