异步fifo，用Verilog编写，包含testbench，已经通过modelsim调试，内含文档和波形图-Asynchronous fifo, to prepare to use Verilog, including testbench, debug modelsim has passed, including documents and wave

APPCM算法和AD/DA芯片驱动在CPLD中的实现，已在实际硬件中测试OK，quartus2环境-APPCM algorithm and AD/DA chip in the drive to achieve in the CPLD has been tested in actual hardware OK, quartus2 environment

同步FIFO 创建一个256x8大小的同步FIFO，并通过串口发送数据初始化FIFO，FPGA内部读取FIFO的数据通过窗口发送到PC-FIFO