一个简单的ADS7843触屏控制芯片的程序。用GPIO口模拟SPI总线控制系统，适合LM3S系列单片机上使用，开发环境：iar-A simple ADS7843 touch screen controller chip process. GPIO SPI bus interface with analog control system, suitable for use on LM3S series microcontroller, the development environment: ia