天嵌开发板附带的都江堰操作系统，包含了都江堰操作系统的源码和使用方法，内附天嵌2440开发板原理图-Days embedded development board with the Dujiangyan operating system, includes the operating system source code and the use of Dujiangyan methods included days embedded 2440 development board schemati

STM32的最小系统，原理图，PCB都有。。。希望有帮助-STM32 minimum system, schematics, PCB has. . . Hope that helps

基于单片机的简易频率计，可测量1HZ—10KHZ的频率，精准率为1 ，可显示占空比。可测量方波，三角波，正昡波.里面包含原理图和源程序，非常实用，大家可以参考参考-Simple microcontroller-based frequency meter measurable frequency 1HZ-10KHZ, the precise rate of 1 , the duty cycle can be displayed. Measurable square, triangle, posit