电阻式触摸屏在智能仪表中的应用

Application of Resistive Touch Screen in the Intelligent Instrument

文中针对四线电阻式触摸屏在智能仪器仪表中的应用 ,介绍了四线电阻式触摸屏的结构原理与两种接口技术 :与内置A/D的单片机接口 ;与专用A/D的接口。针对这两种接口技术 ,详细介绍了接口电路组成及原理 ,通过比较不同的读取控制方式选取了最适合触摸屏控制的中断方式 ,并且分析了触摸屏笔中断控制电路。同时在介绍与专用A/D的接口技术时 ,又简介了专用四线电阻式触摸转换A /D芯片ADS784 3的特性、工作模式以及与 8位AT89C2 0 5 1单片机的接口电路。最后文章阐述了对脉冲干扰的保护措施。实际应用表明 :电路稳定可靠 ,简单实用。

The internal structure and work theory of the 4-wire resistive touch screen are introduced based on the application of the resistive touch screen in the intelligent instrument.And two kinds of interface circuit technology are analyzed:the interface of the touch screen with MCU integrated with A/D and specialized ADC.The composition and principle of the interface circuit are introduced based on two kinds of interface circuit technology.The most suitable interrupt means,which leads to pen interrupt control circuit,is chosen by comparing the different read control means.At the same time,the feature and working model of the special A/D chip for the 4-wire resistive touch screen --ADS7843 and the interface circuit with 8 bit MCU--AT89C2051 are presented.The safeguard against the spikes disturbance is described.It has been shown that this circuit is stabilized and credible,and the operation is quite simple and useful in actual application.