详细74hc595芯片资料The ’HC595 devices contain an 8-bit serial-in, parallel-out shift register that feeds an 8-bit D-type storage register. The storage register has parallel 3-state outputs. Separate clocks are provided for both the shift and storage regis
usb-in-a-nutshell 英文版
USB协议太厚了，这个英文版资料对USB协议做了简单梳理。只做USB设备开发，可以直接先看这个。
(1) most of us are here to develop USB peripherals and (2) it's common to read a standard
and still have no idea how to implement a device. So in the next 7 chapters we focus o
