| 摘要 |
PROBLEM TO BE SOLVED: To detect the presence/absence of a trouble of an AD conversion register without using two channels of AD input ports. SOLUTION: In a microcomputer 10 having the AD conversion register 18 to perform the digital conversion of the analog voltage input in an output part 20 to output the digital signal and an AD input port 16, the output port 20 is directly connected to the AD input port 16. The output port 20 selectively outputs the power source electric potential H and the grounding electric potential L. If either of the predetermined upper rank bits in the AD conversion register 18 with H output is not 1, or if either of the predetermined upper rank bits with L output is not 0, it is judged that the AD conversion register 18 is failed, and the digital conversion value is not used. COPYRIGHT: (C)2003,JPO
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