51 IO port simulation serial communication C source program

Introduction: This article mainly introduces the C source program of 51 IO port simulation serial communication.

#include

sbitBT_SND=P1^0;

sbitBT_REC=P1^1;

/**********************************************

IO port simulation 232 communication program

C program using two methods to occupy timer 0

**********************************************/

#defineMODE_QUICK

#defineF_TMF0

#defineTIMER0_ENABLETL0=TH0;TR0=1;

#defineTIMER0_DISABLETR0=0;

sbitACC0=ACC^0;

sbitACC1=ACC^1;

sbitACC2=ACC^2;

sbitACC3=ACC^3;

sbitACC4=ACC^4;

sbitACC5=ACC^5;

sbitACC6=ACC^6;

sbitACC7=ACC^7;

voidIntTimer0() interrupt1

{

F_TM=1;

}

//Send a character

voidPSendChar(unsignedcharinch)

{

#ifdefMODE_QUICK

ACC=inch;

F_TM=0;

BT_SND=0;//start bit

TIMER0_ENABLE; //Start

while(!F_TM);

BT_SND=ACC0; //Send low bit first

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; //Stop timer

#else

unsignedcharii;

ii=0;

F_TM=0;

BT_SND=0;//start bit

TIMER0_ENABLE; //Start

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; //Stop timer

}

//Receive a character

unsignedcharPGetChar()

{

#ifdefMODE_QUICK

TIMER0_ENABLE;

F_TM=0;

while(!F_TM);//wait until the start position

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; //Stop timer

returnACC;

#else

unsignedcharrch,ii;

TIMER0_ENABLE;

F_TM=0;

ii=0;

rch=0;

while(!F_TM);//wait until the start position

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; //Stop timer

returnrch;

#endif

}

// Check if there is a start bit

bitStartBitOn()

{

return(BT_REC==0);

}

voidmain()

{

unsignedchargch;

TMOD = 0x22; /*Timer 1 is in working mode 2 (8-bit auto-reload), 0 is in mode 2 (8-bit

Automatic reload)*/

PCON=00;

TR0=0; //Start using when sending or receiving

TF0=0;

TH0=(256-96); //9600bps is 1000000/9600=104.167 microseconds

timer is

//

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);

}

}

}