将AT91SAM7X256的三个USART口（两个USART口，和一个DBGU口）配置成三个USART口,Will USART I AT91SAM7X256 three (two USART mouth, and a mouth DBGU) configuration into three USART I

在AT91Sam7x256开发板下，通过修改usart的配置，来实现串口的收发程序-AT91Sam7x256 development board in the next, by modifying the USART configuration, to achieve the serial transceiver procedures

AT91SAM7X256上USART的初始化和使用-AT91SAM7X256 USART