| 摘要 |
PROBLEM TO BE SOLVED: To increase the noise resistance of a serial control circuit with simple constitution. SOLUTION: Serial data to which data for noise detection are added are sent from a noise detection part 15 to a shift register 21 through a data output part 16. The shift register 21 sends the serial data inputted and shifted according to clock pulses to extension ports 27-1 to 27-n from an output latch 22 and outputs the data. The output data outputted from the final stage of the shift register 21, on the other hand, are sent back to the noise detection part 15 of a microcomputer 10 by a data return path 28. The noise detection part 15 compares data for noise detection sent to an extension output port circuit 20 with the sent-back output data to judge whether or not noise is generated.
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