uart.txt

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

//---------------------------------------------------------------------<BR>
//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<BR>
//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<BR>
//定时器初值X=256-SYSCLK*(SMOD+1)/(BAUDRATE*384)<BR>//<BR>
#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</P>
#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
<P>//---------------------------------------------------------------------<BR>
//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</P>
<P>//----------------------------------------------------------------------<BR>
//主函数<BR>//----------------------------------------------------------------------<BR>
void main(void)<BR>
{  
   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<BR>       
     Send_String(trdata,MAX_LEN);       //发送字符串  
     }
   }
    }
//-----------------------------------------------------------------------------------------------------------</P>
<P>//系统时钟初始化
void SYSCLK_Init(void)<BR>
{
uint i;
OSCXCN = 0x67;                           //采用外部晶振22.1184MHz,不分频. 选型OSCXCN=0110,0111
   for(i=0;i&lt;256;i++);                      //等待1ms  
   while(!(OSCXCN&amp;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;                             
-----------------------------<BR>//子函数具体实现<BR>//---
//允许UART0,RX,TX连到2个端口引脚. XBR0=0000,0100<BR>   
XBR1 = 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 0000,0011
P1MDOUT |=0x40;                         //P1.6为推拉方式输出,即LED所在的端口 0100,0000
<P>//串口初始化
void UART0_Init(void)
{
SCON0 = 0x50;                            //选择串口方式1,波特率可变 SCON0=0101,0000
TMOD = 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=4800bps
TL1 = (int)TXVAL;
ES0 = 1;                                //UART0中断开启
TR1 = 1;                                 //启动定时器T1
PCON |= PCONVAL;                //PCON=0x00,SMOD = 0 ; PCON=0x80,SMOD=1
TI0 = 1;                                //声明TX0就绪,可以发送TR0 = 1;
<P>//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)<BR>
{    uint k = 0;<BR>   
do 
{       Send_Char(*(str + k));<BR>        k++;<BR>    } 
while(k &lt; len);

//定时器3中断服务程序<BR>
void Timer3_ISR(void) interrupt 14 using 0<BR>
{ 
TMR3CN &amp;= ~(0x80);  //清TF3
LED = ~LED;   
}
//UART0中断服务程序. 接收字符
void UART0_ISR(void) interrupt 4 using 1<BR>
{
uchar rxch;<BR>   
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<BR>  
readCounts++;
}
}
<P>//-------------------------------------------------------------<BR>//程序结束<BR>//--------------------------------------------------------------</P>