说明：  John Catsoulis编写的Designing Embedded Hardware 。介绍了汇编语言，SPI,I2C,串口，usb,网口等硬件电路设计。模拟电路设计，AVR单片机原理
(John Catsoulis prepared Designing Embedded Hardware. Introduction of assembly language, SPI, I2C, serial, usb, network hardware such as circuit design of the mouth. Analog circuit design, AVR Singlechip Principle)