#include

sbit BT_SND =P1^0;

sbit BT_REC =P1^1

IO 口模拟232通讯程序

使用两种方式的C程序 占用定时器0

#define MODE_QUICK

#define F_TM F0

#define TIMER0_ENABLE TL0=TH0; TR0=1;

#define TIMER0_DISABLE TR0=0;

sbit ACC0= ACC^0;

sbit ACC1= ACC^1;

sbit ACC2= ACC^2;

sbit ACC3= ACC^3;

sbit ACC4= ACC^4;

sbit ACC5= ACC^5;

sbit ACC6= ACC^6;

sbit ACC7= ACC^7;

void IntTimer0() interrupt 1

{

F_TM=1;

}

//发送一个字符

void PSendChar(unsigned char inch)

{

#ifdef MODE_QUICK

ACC=inch;

F_TM=0;

BT_SND=0; //start bit

TIMER0_ENABLE; //启动

while(!F_TM);

BT_SND=ACC0; //先送出低位

F_TM=0;

while(!F_TM);

BT_SND=ACC1;

F_TM=0;

while(!F_TM);

BT_SND=ACC2;

F_TM=0;

while(!F_TM);

BT_SND=ACC3;

F_TM=0;

while(!F_TM);

BT_SND=ACC4;

F_TM=0;

while(!F_TM);

BT_SND=ACC5;

F_TM=0;

while(!F_TM);

BT_SND=ACC6;

F_TM=0;

while(!F_TM);

BT_SND=ACC7;

F_TM=0;

while(!F_TM);

BT_SND=1;

F_TM=0;

while(!F_TM);

TIMER0_DISABLE; //停止timer

#else

unsigned char ii;

ii=0;

F_TM=0;

BT_SND=0; //start bit

TIMER0_ENABLE; //启动

while(!F_TM);

while(ii<8)

{

if(inch&1)

{

BT_SND=1;

}

else

{

BT_SND=0;

}

F_TM=0;

while(!F_TM);

ii++;

inch>>=1;

}

BT_SND=1;

F_TM=0;

while(!F_TM);

#endif

TIMER0_DISABLE; //停止timer

}

//接收一个字符

unsigned char PGetChar()

{

#ifdef MODE_QUICK

TIMER0_ENABLE;

F_TM=0;

while(!F_TM); //等过起始位

ACC0=BT_REC;

TL0=TH0;

F_TM=0;

while(!F_TM);

ACC1=BT_REC;

F_TM=0;

while(!F_TM);

ACC2=BT_REC;

F_TM=0;

while(!F_TM);

ACC3=BT_REC;

F_TM=0;

while(!F_TM);

ACC4=BT_REC;

F_TM=0;

while(!F_TM);

ACC5=BT_REC;

F_TM=0;

while(!F_TM);

ACC6=BT_REC;

F_TM=0;

while(!F_TM);

ACC7=BT_REC;

F_TM=0;

while(!F_TM)

{

if(BT_REC)

{

break;

}

}

TIMER0_DISABLE; //停止timer

return ACC;

#else

unsigned char rch,ii;

TIMER0_ENABLE;

F_TM=0;

ii=0;

rch=0;

while(!F_TM); //等过起始位

while(ii<8)

{

rch>>=1;

if(BT_REC)

{

rch|=0x80;

}

ii++;

F_TM=0;

while(!F_TM);

}

F_TM=0;

while(!F_TM)

{

if(BT_REC)

{

break;

}

}

TIMER0_DISABLE; //停止timer

return rch;

#endif

}

//检查是不是有起始位

bit StartBitOn()

{

return (BT_REC==0);

}

void main()

{

unsigned char gch;

TMOD=0x22; /*定时器1为工作模式2(8位自动重装)，0为模式2(8位

自动重装) */

PCON=00;

TR0=0; //在发送或接收才开始使用

TF0=0;

TH0=(256-96); //9600bps 就是 1000000/9600=104.167微秒 执行的

timer是

//

104.167*11.0592/12= 96

TL0=TH0;

ET0=1;

EA=1;

PSendChar(0x55);

PSendChar(0xaa);

PSendChar(0x00);

PSendChar(0xff);

while(1)

{

if(StartBitOn())

{

gch=PGetChar();

PSendChar(gch);

}

}

}