实现fifo的基本功能。使用Verilog能够实现的同步数据先入先出功能，简单易懂，并带有相应的测试文件-Fifo realize the basic functions. Be able to use the Verilog implementation of the synchronous data FIFO functions, easy to understand, with the corresponding test file

The SC16C752B is a dual Universal Asynchronous Receiver/Transmitter (UART) with 64-byte FIFOs, automatic hardware/software flow control, and data rates up to 5 Mbit/s (3.3 V and 5 V). The SC16C752B offers enhanced features. It has a Transmission