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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。
In this paper, based on the application of four-wire resistive touch screen in intelligent instrumentation, the principle of four-wire resistive touch screen and two interface technologies are introduced: the interface with built-in A / D microcontroller and the interface with dedicated A / D. According to the two interface technologies, the interface circuit and the principle are introduced in detail. By comparing different read control methods, the most suitable interrupt mode for touch-screen control is selected, and the touch-screen pen interrupt control circuit is analyzed. At the same time when introducing the interface technology with dedicated A / D, the characteristics, working mode and the interface circuit with the 8-bit AT89C2 0 5 1 MCU are also introduced briefly. The last article describes the protection against impulse interference. Practical application shows that: the circuit is stable and reliable, simple and practical.