| 摘要 |
PURPOSE:To prevent constituent elements from increasing in number by obtaining a D/A converting function by using a serial data input and output function provided to a microcomputer in common. CONSTITUTION:When a serial data output mode is set in an FF 5 for mode setting, a shift control circuit 5 operates and transfers data from a preset shift register 2 successively in series with an outputted shift clock. When the transfer is completed, the shift control circuit 4 generates an end signal indicating the end of the transfer. When a D/A conversion mode is set in the FF 5 for mode setting, on the other hand, a gate circuit 7 is controlled according to the setting contents of a variation request FF 6 to switch operation for outputting the end signal generated by the shift control circuit 4 and operation for outputting a control signal for the start of the operation of the shift control circuit 4 without outputting the end signal.
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