| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, even if there is no change in externally inputted analog values in a semiconductor integrated circuit incorporating an A/D converter circuit and a CPU, upon receipt of a conversion completion notice from the A/D converter circuit when the A/D converter circuit is used, the CPU needs to confirm the A/D conversion result with interrupting main program processes, and further to reconfirm the conversion result after repeating the A/D conversion once. SOLUTION: An A/D converter circuit 2 completes an A/D conversion operation to issue an A/D conversion completion notice (signal 109) to a CPU 6 only when the level of an externally inputted analog signal varies. The circuit 2 may generate a completion notice after verifying that the analog signal level is in a stationary state after its transient state, thus omitting the confirmation operation of the A/D conversion result by the CPU 6 after receiving the completion notice, thus reducing the load of the CPU 6. COPYRIGHT: (C)2005,JPO&NCIPI
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