C8051F系列单片机串口通讯程序

C8051F系列单片机串口通讯程序

采用C8051F020单片机

//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)

/#include

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=0110,0111 for(i=0;i<256;i++); //等待>1ms

while(!(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=0000,0100

XBR1 = 0x00;

XBR2 = 0x40; //交*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

}

//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;

}

//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TF3

LED = ~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