| 摘要 |
PURPOSE:To make an efficient use of an output port of a micro-computor, by providing an output unit which is capable of producing a digital signal of a predetermined bit number calculated and determined by the micro-computer from a single output port. CONSTITUTION:In a control apparatus such as an electronic governor for controlling the injection quantity of fuel according to the engine speed, clock pulses given from a clock pulse generator incorporated in a CPU11 and pulse signals having a predetermined pulse width and passed through a delay circuit 12 are applied from the CPU11 to a 12-bit binary counter 13. The number of clock pulses counted by the counter 13 is applied to a 12-bit latch circuit 14 and it is latched therein. Then, a 12-bit digital signal is produced from twelve output ports of the latch circuit 14 and applied to a 12-bit D/A converter 15 composed, for instance, of an R-2R ladder net work, and a required actuator or actuators are controlled according to the output signal of said converter 15. |
