IIC and xlinx official description of spi interface

USB转RS232RSTTLRS485FT232+SP213串口的原理图AD画的(USB to RS232RSTTLRS485FT232+SP213 serial port schematic AD drawing)

基于FPGA的出租车计价器，欢迎大死同学多多交流(FPGA-based Taximeter, welcomes the dead students more exchanges)

乘法器是硬件设计中的很常见也很重要的一个模块，它的VHDL硬件实现很好的解决了软件编程中做乘法速度慢的问题，在实时高速系统应用中或DSP软核或数字信号处理硬件实现算法中，经常能使用到乘法器，所以经典的高速乘法器IP 很有参考价值-Multiplier is a common and important module in hardware designing.Its VHDL addresses the low speed of multiplication in software programming. Multiplier is often used in real-time high-speed system application , DSP soft core or hardware implementation of digital signal processing,so it is worthful to know classic high-speed multiplier IP

DOCUMENT ON DISTRIBUTED ARITHMATIC

说明：  一个简单的键盘接口模块程序，对键盘输入的数据和时钟信号进行过滤。过滤后的数据信号PS2Df将被送入两个11位移位寄存器中(A simple keyboard interface module program filters keyboard input data and clock signals. The filtered data signal PS2Df will be fed into two 11-bit displacement registers.)

VHDL写时钟，分频模块什么，实现计时。定点报时，定点闹钟，显示年月日。(verilog HDL)

verilog 教程 PPT版本 语法 结构 设计技巧等(Verilog tutorial PPT version)

dc的应用规范，以及一些基础的操作指导，注意事项等(dc application specification, as well as some basic instructions, precautions, etc.)

source vhdl code of D flipflop logic

关于usb调试相关测试 代码，用于测试和适配等(usb coding for testing , verigy, for studing usb and fpga)