ADS7846/7843芯片 适合用在4线制触摸屏，它通过标准SPI协议和CPU通信，操作简单，精度高，当触摸屏被按下时（即有触摸事件发生）则ADS7846向CPU发中断请求，CPU接到请求后，应延时一下再响应其请求，目的是为了消除抖动使得采样更准确。如果一次采样不准确，可以尝试多次采样取最后一次结果为准，目的也是为了消除抖动。-ADS7846/7843 chip suitable for use in 4-wire touch screen, it is through a standard SPI protocol and CPU communication, simple operation and high precision, when the touch screen is pressed (that is, the incident has touch) are ADS7846 issued to CPU interrupt request, CPU access to the request should be delayed and then respond to their request, aimed at the elimination of jitter in order to make a more accurate sampling. If a sample is not accurate, you can try many times the last time check the results of sampling, whichever it is also aimed at the elimination of jitter.