The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 31, 2011
Filed:
Mar. 03, 2008
Peter C. Hsiang, Santa Clara, CA (US);
Raymond O. Chock, San Jose, CA (US);
Mark Hess, San Francisco, CA (US);
Peter C. Hsiang, Santa Clara, CA (US);
Raymond O. Chock, San Jose, CA (US);
Mark Hess, San Francisco, CA (US);
Maxim Integrated Products, Inc., Sunnyvale, CA (US);
Abstract
A high security microcontroller (such as in a point of sale terminal) includes tamper control circuitry for detecting vulnerability conditions: a write to program memory before the sensitive financial information has been erased, a tamper detect condition, the enabling of a debugger, a power-up condition, an illegal temperature condition, an illegal supply voltage condition, an oscillator fail condition, and a battery removal condition. If the tamper control circuitry detects a vulnerability condition, then the memory where the sensitive financial information could be stored is erased before boot loader operation or debugger operation can be enabled. Upon power-up if a valid image is detected in program memory, then the boot loader is not executed and secure memory is not erased but rather the image is executed. The tamper control circuitry is a hardware state machine that is outside control of user-loaded software and is outside control of the debugger.