uart.h

mega128的串口发送文件.可以发送0X55上位机使用串口调试工具就可以接收了.

#define BAUD    9600            //波特率采用9600bps
#define CRYSTAL 4000000			//系统时钟4MHz

//计算和定义波特率设置参数
#define BAUD_SETTING (unsigned int)((unsigned long)CRYSTAL/(16*(unsigned long)BAUD)-1)
#define BAUD_H (unsigned char)(BAUD_SETTING>>8)
#define BAUD_L (unsigned char)(BAUD_SETTING)

// USART控制和状态寄存器的标志位定义
#define RXC  7          // UCSRA位定义
#define TXC  6
#define UDRE 5
#define FE   4
#define DOR  3
#define PE   2
#define U2X  1
#define MPCM 0
#define RXCIE 7         // UCSRB位定义
#define TXCIE 6
#define UDRIE 5
#define RXEN  4
#define TXEN  3
#define UCSZ2 2
#define RXB8  1
#define TXB8  0
#define URSEL 7         // UCSRC位定义
#define UMSEL 6
#define UPM1  5
#define UPM0  4
#define USBS  3
#define UCSZ1 2
#define UCSZ0 1
#define UCPOL 0 

#define FRAMING_ERROR (1<<FE)
#define PARITY_ERROR (1<<PE)
#define DATA_OVERRUN (1<<DOR)
#define DATA_REGISTER_EMPTY (1<<UDRE)