四分频的程序，输出clkout0就是二分频，clkout1是四分频

计数器是数字系统中使用最多的时序电路，它不仅能用于对时钟脉冲计数，还可以用于分频、定时、产生节拍脉冲和脉冲序列以及进行数字运算等。(Counter is the most frequently used sequential circuit in digital system. It can be used not only for counting clock pulses, but also for frequency division, timing, generating beat pulses and pulse sequences, and performing digital operations.)

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说明：  实现主干道交通灯显示，以状态机程序实现，并用数码管进行红绿灯倒计时的显示，内置计数模块，交通灯控制模块，数码管显示模块，并对各模块用电路图的方式进行连接。对于学习VHDL语言有所帮助。(The main road traffic light display is realized by the state machine program, and the digital tube is used to display the traffic light countdown. The counting module, the traffic light control module and the digital tube display module are built in, and each module is connected by the circuit diagram. It is helpful for learning VHDL.)

完成一个1位全减器的设计。以全减器为元件程序完成8位减法器设计。(Completed a one minus the whole design. Full reduction is to complete eight subtraction element program design.)

4*4键盘设计，能运行，是我自己编译的，是初学者的工具(4* 4 keyboard design, can run my own compilation, is a tool for beginners)

C源碼16C550 串口驅動，使用中斷收送RS232資料(16C550 UART Driver)

ISE 9.2 serials working

说明：  64位数据的CRC-32校验的，Verilog实现，算法并行优化(64-bit data CRC-32 checksum, Verilog implementation of a parallel optimization algorithm)

quartus II 13.0 DDS工程文件，采用VHDL编写，可输出正交两路正弦信号。可以直接用modelsim-alter 仿真(quartus II 13.0 DDS project file, using VHDL written two orthogonal sinusoidal output signals. Can be simulated directly modelsim-alter)

共两个文件，一个是对网络芯片W5500进行控制的master spi接口，另一个是w5500命令控制逻辑，命令格式按照w5500芯片的要求，分为地址段，控制段和数据段进行统一控制。此外提供w5500芯片初始化及读写控制流程图。(A total of two documents, one is the master SPI interface for network control chip W5500, the other is a w5500 command control logic, command format in accordance with the requirement of w5500 chip, divided into address segment, unified control and data segments. In addition to provide w5500 chip initialization and read and write control flow chart.)