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:
Nov. 19, 1991
Filed:
Mar. 19, 1991
Applicant:
Inventors:
Yasuhiro Wakimoto, Yokohama, JP;
Tetsuo Suzuki, Tokyo, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F / ; G06F / ;
U.S. Cl.
CPC ...
395400 ; 3642864 ; 3642865 ; 3642329 ; 3642466 ; 36424531 ; 364D / ;
Abstract
A single-chip microcomputer connectable to an external memory for expanding the address space, and having a first mode of operation in which the available memory region is both the region of an internal ROM and the external memory, and having a second mode of operation in which the available memory region is the region of the external memory only. An inhibiting device is provided for inhibiting the switching from the second mode to the first mode, thereby ensuring that the contents of the internal ROM cannot be read-out.