| 摘要 |
<p>PURPOSE:To improve the universal applicability of a digital control system with a small number of terminals by sharing a part of an analog input terminal and a part of a digital input terminal and using selectively these shared parts as the digital or analog input terminals according to programs. CONSTITUTION:When terminals P4 and P5 are used as digital input terminals, a program is compiled so that the input data to be given to a register 17 for control of a multiplexer 13 are not selected by the signal received from those terminals. Furthermore a program is compiled based on a fact that the digital signals are handled in case the addresses are designated fro latch circuits 15a, 15b, etc. in a register 15 corresponding to the terminals P4 and P5. If those shared terminals P4 and P5 are used as analog input terminals, these terminals are selected by the multiplexer 13 via the register 17. At the same time, the input of analog input signals is attained by setting the latch output setting the directivity at '0' together with an output buffer amplifier set at a high impedance.</p> |
