A/D、D/A转换程序设计 加深理解逐次逼近法模数转换器的特征和工作原理，掌握ADC0809的接口方法以及A/D输入程序的设计和调试方法。-A/D, D/A conversion process designed to deepen understanding of the successive approximation ADC characteristics and working principle of the interface methods have ADC0809 and A/D