C8051F单片机和PC机串口通讯程序//------------------------------------------------------------------//串口编程--接收PC发过来的字符串,回发字符串.发送期间中断控制LED灯闪烁//采用外部晶振22.1184MHz 使用定时器1,方式2产生波特率,SMOD = 0或者1//定时器初值X=256-SYSCLK*(SMOD+1)/(BAUDRATE*384)////程序编写: 郭郭//编程时间: 2005,12,30//最后修改: 2005,12,31//------------------------------------------------------------------#include <C8051F020.h>sfr16 TMR3RL = 0x92; //定时器3重装载寄存器sfr16 TMR3 = 0x94; //定时器3计数器#define uchar unsigned char#define uint unsigned int//------------------------------------------------------------------//参数设置区//------------------------------------------------------------------#define BAUDRATE 4800 //波特率bps#define CLKOUT 22118400 //外部晶振,修改也要修改OSCXCN#define SMODVAL 0 //SMOD的值,修改请也修改PCONVAL#define PCONVAL 0x00 //PCON的值,=0x00时SMOD0=0; =0x80时SMOD0=1#define TXVAL (256-CLKOUT*(SMODVAL+1)/BAUDRATE/384) //定时器初值#define MAX_LEN 10 //每次接收/发送字符串的长度//------------------------------------------------------------------//全局变量//------------------------------------------------------------------sbit LED = P1^6; //LED '1'亮 '0'灭bit readFlag = 0; //读标志uchar readCounts = 0; //已经读取的字符个数,与MAX_LEN比较uchar idata trdata[MAX_LEN]; //要接收/发送的字符串//------------------------------------------------------------------//子函数声明//------------------------------------------------------------------void SYSCLK_Init(void); //系统时钟初始化void PORT_Init(void); //端口初始化void UART0_Init(void); //串口UART0初始化void Send_Char(uchar ch); //发送单个字符void Send_String(uchar * str, uint len); //发送一个字符串void UART0_ISR(); //串口中断服务程序,接收字符void Timer3_Init(uint counts); //定时器3初始化void Timer3_ISR(void); //定时器3中断服务程序//------------------------------------------------------------------//主函数//------------------------------------------------------------------void main(void){WDTCN = 0xde; //禁止看门狗WDTCN = 0xad;SYSCLK_Init(); //时钟初始化PORT_Init(); //端口初始化UART0_Init(); //串口初始化Timer3_Init(CLKOUT/12/10); //定时器初始化EA = 1; //开全局中断while(1){if(readFlag) //已经读取{readFlag = 0; //清零Send_String(trdata,MAX_LEN); //发送字符串}}}//------------------------------------------------------------------//子函数具体实现//------------------------------------------------------------------//系统时钟初始化void SYSCLK_Init(void){uint i;OSCXCN = 0x67; /采用外部晶振22.1184MHz,不分频. 选型OSCXCN=0110,0111for(i=0;i<256;i++); //等待>1mswhile(!(OSCXCN&0x80)); //查询直到XTLVLD=1,晶振稳定OSCICN = 0x88;//切换到外部振荡器,允许时钟失效监测器. OSCICN=1000,1000}//端口初始化void PORT_Init(void){XBR0 = 0x04; //允许UART0,RX,TX连到2个端口引脚. XBR0=0000,0100XBR1 = 0x00;XBR2 = 0x40; //交叉开关使能P0MDOUT |= 0x03; //P0.0为推拉方式输出,即TX0,RX0所在的端口 0000,0011P1MDOUT |=0x40; //P1.6为推拉方式输出,即LED所在的端口0100,0000}//串口初始化void UART0_Init(void){SCON0 = 0x50; //选择串口方式1,波特率可变SCON0=0101,0000TMOD = 0x20; //选择T1,方式2,自动再装入8位计数器TH1 = (int)TXVAL;//T1初值,根据波特率,时钟等计算. 0xF4,bps=4800bpsTL1 = (int)TXVAL;ES0 = 1; //UART0中断开启TR1 = 1; //启动定时器T1PCON |= PCONVAL; //PCON=0x00,SMOD = 0 ; PCON=0x80,SMOD=1TI0 = 1; //声明TX0就绪,可以发送TR0 = 1;}//定时器初始化void Timer3_Init(uint counts){TMR3CN = 0x00; //禁止定时器T3,清TF3,采用SYSCLK/12为时基TMR3RL = -counts; //初始化重装载值TMR3 = 0xffff; //设置为立即重装载EIE2 |= 0x01; //T3中断开启TMR3CN |= 0x04; //启动T3}//发送单个字符void Send_Char(uchar ch){SBUF0 = ch; //送入缓冲区while(TI0 == 0); //等待发送完毕TI0 = 0; //软件清零}//发送字符串,调用Send_Char() len字符串长度void Send_String(uchar * str,uint len){uint k = 0;do{Send_Char(*(str + k));k++;} while(k < len);}//定时器3中断服务程序void Timer3_ISR(void) interrupt 14 using 0{TMR3CN &= ~(0x80); //清TF3LED = ~LED;}//UART0中断服务程序. 接收字符void UART0_ISR(void) interrupt 4 using 1{uchar rxch;if(RI0) //中断标志 RI0=1 数据完整接收{RI0 = 0; //软件清零rxch = SBUF0; //读缓冲if(readCounts>=MAX_LEN){readCounts = 0;readFlag = 1;}trdata[readCounts] = rxch; //存入数组,供发送readCounts++;}}//-------------------------------------------------------------//程序结束//--------------------------------------------------------------。
