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:
Jan. 10, 1989
Filed:
Jun. 22, 1981
Jeffrey D Bellay, Houston, TX (US);
Kevin C McDonough, Houston, TX (US);
Michael W Patrick, Houston, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A microcomputer device contains a CPU with an arithmetic/logic unit and data/address registers on a single semiconductor integrated circuit having on-chip macrocode and microcode storage. A macrocode word is fetched from an on-chip ROM and stored in an instruction register in the CPU, then a sequence of microcode words is fetched from the microcode store based on this macrocode word. A check-code based on some function of all macrocode bits is stored in on-chip ROM upon manufacture. To test a device after fabrication is complete, a test program (resident in ROM or downloaded into on-chip RAM) is executed to address all bytes of macrocode and perform some cummulative function on it via the ALU to see if the same check-code is produced. If so, an output indicates a good unit.