毕业设计英文资料 触摸屏.doc

Although touch screens are rapidly becoming more popular most developers have never created one before. Here is a step by step design guide that leads you through the hardware and software required to make touch screens work the first time. Touch screens are everywhere. Industrial control systems, consumer electronics, and even medical devices are commonly equipped with touch-screen input. We use touch screens every day without even thinking about it. You might get cash at your ATM, sign for a package, check in for your flight, or look up a telephone number all by using a touch screen. This article describes two relatively new CPU offerings that provide built-in support for touch-screen input. Ill show you how to write a software driver that will configure, calibrate, and continuously respond to touch-screen input using either of these microprocessors. The result will be working code that youre free to download and use as a baseline for your own efforts. Touch-screen technologiesBefore we can begin writing a touch-screen driver we have to have some basic understanding of how the hardware works. Many different touch technologies convert pressure or touch at a screen location into meaningful numerical coordinates. Some of these technologies include resistive, surface wave, infrared, and capacitive touch screens. For an excellent overview of the available technologies, you can go to and . For this article Ill focus on resistive touch screens. Resistive touch screens are very popular, and theyre the type of touch screen youll find integrated with many evaluation boards and development kits. Resistive touch screens are popular mainly because theyre inexpensive and electrically straightforward to add to your system. Resistive touch screens are so named because they are basically resistive voltage dividers. Theyre composed of two resistive sheets separated by a very thin insulator usually in the form of plastic micro-dots. When you touch the screen, you deform the t