说明：  一本经典而且很实用的嵌入式系统学习的入门教材，介绍了WiFi无线网络、PWM、485网络驱动、红外学习与发射、网络编程，很值得大家学习
(A classic and very useful introductory embedded systems learning materials, introduced a WiFi wireless network, PWM, 485 network drive, IR learning and launch, network programming, it was worthwhile for us to learn)