Freescale Semiconductor,inc.

John E Spittal, Jr

Thomas E Tkacik

Lawrence Loren Case

Douglas Allan Hardy

Michael D Fitzsimmons

Mark D Redman

Darrell L Carder

Jonathan Lutz

Gregory Schmidt

Steven R Tugenberg

Steven Tugeberg

A processor, scan controller, and method for protecting sensitive information from electronic hacking is disclosed. To maintain the security of the sensitive data present in a processor, the scan controller denies access to the scan chain until data is cleared from scan-observable portions of the processor, then clears the scan chain again prior to exiting test mode and resuming normal operation. Clearing or otherwise modifying data stored in the scan-observable portions of a processor when transitioning to and/or from a test mode will prevent unauthorized personnel from simply shifting secure data out of the scan chain, and from pre-loading data into the scan chain prior to normal operation in an attempt to set sensitive state information.

Method and apparatus for secure scan testing

Growing community of inventors

Waddell, AZ, United States of America

John E Spittal, Jr