公开(公告)号：AT534077T

公开(公告)日：2011-12-15

申请号：AT06735222

申请日：2006-02-16

Applicant: MICROCHIP TECH INC

Inventor： MASGRAS CRISTIAN ,  PYSKA MICHAEL ,  BOLES EDWARD ,  TRIECE JOSEPH ,  WOJEWODA IGOR ,  CHEN MEI-LING

IPC: G06F11/27 ,  G11C29/46

Abstract: A special mode key match comparison module has N-storage elements and a special mode key match comparator. The N-storage elements accumulate a serial data stream, and then determine whether a digital device should operate in a normal user mode, in a public programming mode, or in a particular private test mode. To reduce the possibility of accidentally decoding a false test or programming mode, the data stream has a sufficiently large number of N-bits to substantially reduce the probability of a false decode. To further reduce the possibility of accidentally decoding a programming or test mode, the special mode key match comparison module may be reset if less or more than N-clocks are detected during the accumulation of the N-bit serial data stream. The special mode key match data patterns may represent a normal user mode, a public programming mode, and particular private manufacturer test modes.