单片机的应用在后PC时代得到了前所未有的发展，但对处理器的综合性能要求也越来越高。综观单片机的发展，以应用需求为目标，市场越来越细化，充分突出以“单片”解决问题，而不像多年前以MCS51/96等处理器为中心，外扩各种接口构成各种应用系统。-Its applications have been in the post-PC era of unprecedented development, but the overall performance of the processors are increasingly high requirements. Looking at the development of microcontroller to application requirements for the target, the market becomes more refined, full prominence to " chip"　to solve the problem, rather than to MCS51/96 so many years ago as the central processor, the external expansion interface consists of a variety of kinds of applications.