用单片机I/O引脚实现A/D功能的原理与应用

The Principle and Application of the Realization of the A/D Function with MCU I/O

本文利用现行有些单片机输入,输出(I/O)引脚的输入阻抗高、输出驱动能力强的特性,分析了用I/O引脚实现模数转移的原理,并在此基础上,提出了这种方法在电阻测量、键盘检测中的应用。通过该方法的讨论可开阔解决问题的思路。

The A/D transformation principle with MCU I /O is analyzed by the means of using the high-er input resistance and the stronger output driver ability of some existing MCU.Based on this,the application in surveying a resistance and testing a key is presented.The view of solving problems can be broadened through the discussion on the method.