学习A/D 接口原理，了解实现A/D 系统对于系统的软件和硬件要求。阅读ARM 芯片文档，掌握ARM 的A/D 相关寄存器的功能，熟悉ARM 系统硬件的A/D 相关接口。利用外部模拟信号编程实现ARM 循环采集AIN0通道，并且在超级终端上显示。(Learn the A/D interface principle, understand the A/D system for the system software and hardware requirements. Read ARM chip document, master the function of A/D related register of ARM, be familiar with A/D interface of ARM system hardware. Using external analog signal programming, ARM cycle to collect AIN0 channel, and displayed on the super terminal.)