前言

DS2450是一線式4通道逐次逼近式A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器" title="A/D轉(zhuǎn)換器">A/D轉(zhuǎn)換器，其輸入電壓范圍、轉(zhuǎn)換精度位數(shù)、報(bào)警門限電壓可編程；每個(gè)通道有各自的存儲(chǔ)器以存儲(chǔ)電壓范圍設(shè)置、轉(zhuǎn)換結(jié)果、門限電壓等參數(shù)；普通方式下串行通信速率達(dá)16.3kbps，超速工作時(shí)速率達(dá)142kbps，片內(nèi)16位循環(huán)冗余校驗(yàn)碼生成器可用于檢測(cè)通信的正確性；DS2450采用8引腳SOIC小體積封裝形式，既可用單5V電源供電，也可采用寄生電源方式供電。電路正常工作時(shí)僅消耗2.5mW功率，不工作時(shí)消耗25μW。多個(gè)DS2450或其他功能的具有MicroLAN接口的一線式芯片可以并聯(lián)，CPU只需一根端口線就能與諸多一線式芯片通信，占用微處理器的端口較少，可節(jié)省大量的引線和邏輯電路。

2 DS2450的引腳排列和內(nèi)部結(jié)構(gòu)

DS2450為8引腳SOIC型封裝，其管腳功能如下：

1腳（VDD）：工作電源接入端
2腳（N.C）：空引腳
3腳（DATA）：串行數(shù)據(jù)輸入/輸出端
4腳（GND）：接地端
5腳（AIN－A）：A路模擬電壓輸入端
6腳（AIN－B）：B路模擬電壓輸入端
7腳（AIN－C）：C路模擬電壓輸入端
8腳（AIN－D）：D路模擬電壓輸入端
 

DS2450的內(nèi)部結(jié)構(gòu)如圖1所示。光刻ROM中的64位序列號(hào)是出廠前被光刻好的，它可以看作是該DS2450的地址序列碼；64位光刻ROM的排列是：開始8位（20H）是產(chǎn)品類型標(biāo)號(hào)，接著的48位是該DS2450自身的序列號(hào)，最后8位是前面56位的循環(huán)冗余校驗(yàn)碼（CRC=X8＋X5＋X4＋1）。光刻ROM的作用是使每一個(gè)一線式器件的地址都各不相同，以便實(shí)現(xiàn)一根總線上掛接多個(gè)一線式電路。

對(duì)于一線端口，在ROM功能建立之前，其它功能是無(wú)法實(shí)現(xiàn)的。總線控制器必須首先通過(guò)DATA引腳對(duì)DS2450提供7個(gè)ROM功能控制命令（8位）之一：（1）讀ROM，命令字[33H]；（2）匹配ROM[55H]；（3）搜索ROM[F0H]；（4）跳過(guò)ROM[CCH]；（5）條件搜索ROM[ECH]；（6）超速跳過(guò)ROM[3CH]；（7）超速匹配ROM[69H]。其中，超速跳過(guò)ROM或超速匹配ROM命令執(zhí)行后，串行通信速率可高達(dá)142kbps。如果多個(gè)器件連接在一線上，這些命令對(duì)每個(gè)器件的64位ROM部分進(jìn)行操作，并挑選出一個(gè)特定的器件。對(duì)選中的DS2450，執(zhí)行下一步的A/D轉(zhuǎn)換控制命令以及讀寫存儲(chǔ)器的命令，所有命令或數(shù)據(jù)的讀/寫均從最低位開始。

3 存儲(chǔ)器組織方式

DS2450內(nèi)部有24個(gè)地址毗連的8位存儲(chǔ)器，可將其分成3頁(yè)，每頁(yè)8字節(jié)。DS2450的存儲(chǔ)器組織方式及各位含義如表1所示（高位地址為00H）。

第0頁(yè)為A/D轉(zhuǎn)換結(jié)果存儲(chǔ)器，每個(gè)通道占2個(gè)字節(jié)16位，芯片上電復(fù)位時(shí)該頁(yè)清0；其中00H、01H存儲(chǔ)A通道轉(zhuǎn)換結(jié)果，LSBA為最低位，MSBA為最高位；02H、03H存儲(chǔ)B通道轉(zhuǎn)換結(jié)果;04H、05H存儲(chǔ)C通道轉(zhuǎn)換結(jié)果;06H、07H存儲(chǔ)D通道轉(zhuǎn)換結(jié)果，對(duì)應(yīng)位含義與A通道相同。

第1頁(yè)為A/D轉(zhuǎn)換控制與狀態(tài)存儲(chǔ)器，08H、09H對(duì)應(yīng)于A通道，其余通道依次類推，各位含義相同。RC3、RC2、RC1、RC0的組合控制A/D轉(zhuǎn)換的精度位數(shù)，0000為16位、0001為1位、……、1111為15位；特別值得注意的是，若控制轉(zhuǎn)換精度不足16位，則在轉(zhuǎn)換結(jié)果的“低位”補(bǔ)0，湊足16位，因此讀出結(jié)果的16位值中,哪些是有效位與RC3、RC2、RC1、RC0的組合有關(guān)。對(duì)于用作模擬量輸入的通道，輸出使能位OE必須為0，否則模擬輸入不被接受，轉(zhuǎn)換結(jié)果始終全為0，而此時(shí)輸出控制位OC可以不必關(guān)心。不用作模擬量輸入的通道可以作為漏極開路的數(shù)字輸出端，外接上拉電阻器和工作電源，在輸出使能位OE=1時(shí)，若輸出控制位OC寫入1，則輸出高電平，OC寫入0，則輸出低電平。IR控制輸入電壓范圍，IR=1時(shí)模擬輸入高限為5.10V，IR=0時(shí)輸入高限為2.55V。AEH、AEL分別為高、低門限電壓報(bào)警允許控制端；AFH、AFL分別為模擬輸入是否超過(guò)規(guī)定的高門限、低于規(guī)定的低門限的狀態(tài)指示位，若輸入超限，相應(yīng)位自動(dòng)置1。上電復(fù)位標(biāo)志位POR與通道無(wú)關(guān)，上電復(fù)位時(shí)4個(gè)POR自動(dòng)置1，說(shuō)明控制字和門限值等未準(zhǔn)備好，該位可用軟件清0。表中為0的位無(wú)效，讀出時(shí)始終為0且不能寫入1。DS2450上電復(fù)位時(shí)，默認(rèn)的控制/狀態(tài)數(shù)據(jù)的低位為08H、高位為8CH，即4個(gè)通道均作為模擬輸入通道、8位轉(zhuǎn)換精度、輸入高限2.55V、允許高低限報(bào)警。

第2頁(yè)為各通道輸入高/低限報(bào)警值存儲(chǔ)器，10H存放A通道低門限8位報(bào)警值、11H存放A通道高門限8位報(bào)警值，其余通道依次類推，各位含義相同。在判斷是否超限時(shí)，只將存儲(chǔ)的門限值與轉(zhuǎn)換結(jié)果的高8位進(jìn)行比較，然后自動(dòng)改變AFH、AFL的狀態(tài)。上電復(fù)位時(shí)，高限值自動(dòng)設(shè)置為FFH，低限值自動(dòng)設(shè)置為00H。

4 轉(zhuǎn)換與讀/寫控制

4．1轉(zhuǎn)換控制

通過(guò)DS2450的DATA端串行送出轉(zhuǎn)換命令字[3CH]，隨后送出通道選擇字和預(yù)置控制字，啟動(dòng)A/D轉(zhuǎn)換器進(jìn)行轉(zhuǎn)換。DS2450的通道選擇字和預(yù)置控制字的各位含義如表2所示。

在通道選擇字中，對(duì)應(yīng)位為1表示該通道參與轉(zhuǎn)換。同時(shí)選擇多個(gè)通道時(shí)，其轉(zhuǎn)換順序?yàn)锳→B→C→D，未選中的通道被跳過(guò)。其A/D轉(zhuǎn)換的時(shí)間可用下式近似計(jì)算：轉(zhuǎn)換時(shí)間=通道數(shù)×轉(zhuǎn)換精度位數(shù)×80μs＋160μs。當(dāng)所有通道轉(zhuǎn)換完畢，發(fā)讀存儲(chǔ)器命令可以獲得轉(zhuǎn)換結(jié)果和對(duì)應(yīng)的狀態(tài)。
 

預(yù)置控制字可以對(duì)相應(yīng)通道的轉(zhuǎn)換結(jié)果存儲(chǔ)器進(jìn)行預(yù)置。SET、CLR=00，不預(yù)置，保持上次轉(zhuǎn)換值；SET、CLR=01，轉(zhuǎn)換前預(yù)置為全0；SET、CLR=10，預(yù)置為全1；SET、CLR=11，無(wú)效組合。