| 摘要 |
<p>PURPOSE:To improve the universal applicability of a microprocessor with a small number of terminals by securing the common use with an external terminal connected to a part for at least some of plural analog input terminals for plural analog inputs. CONSTITUTION:When shared terminals P4 and P5 are used as analog input terminals, these terminals are selected by a multiplexer 13 via a register 17. Then the input of analog signals are attained by setting the latch output setting the directivity at '0' together with an output buffer amplifier set at a high impedance. In this case, the addresses of latch circuits 15a, 15b, etc. are not designated for a register 15 corresponding to the terminals P4 and P5. Then different timings are set for designation of addresses between the register 15 and a register 16 when transfer of digital signals are carried out to an external circuit to the register 15 for digital signals which are not used in common.</p> |
