MICROCOMPUTER, CONVERSION ACCURACY TUNING METHOD, D/A CONVERSION METHOD AND A/D CONVERSION METHOD

摘要

PROBLEM TO BE SOLVED: To prevent danger of malfunction to be caused by undesired rewriting of correction data for improving conversion accuracy of an on-chip A/D conversion circuit or D/A conversion circuit. SOLUTION: This microcomputer is provided with an erasable and writable nonvolatile memory (4), conversion circuits (15, 16) and a CPU (2). The conversion circuit(s) is(are) any one of or both of A/D conversion circuit and D/A conversion circuit. The nonvolatile memory saves an error-correcting data for correcting conversion accuracy of said conversion circuit in a predetermined storage area (4T). The predetermined storage area is a protect area wherein erasure and write are permitted in a test mode, and erasure and write are inhibited in the other operating mode. When performing an ordinary operation with reset/start, the error-correcting data are stored in the protect area, so that the area is blocked from being easily rewritten even when a microcomputer is in out of control. COPYRIGHT: (C)2004,JPO&NCIPI