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serial output problem

Nir boh

hi,
i'm using a- 80c31 microcontroller to send the status
of port bits: p3.3,p3.4,p3.5 using serial comm.
my program works fine only in simulation and i cant
get an idea where is the problem.
i checked the TX pin(11) with a scope and it seems that no data are being sent.

please help...

#include <Reg51.h>
sbit Input1 = 0xB3;     /* P3.3  */
sbit Input2 = 0xB4;     /* P3.4  */
sbit Input3 = 0xB5;     /* P3.5  */

unsigned int Tmr1 = 0;
unsigned int Tmr2 = 0;
unsigned int Tmr3 = 0;

void SendStatus() {
if (Input1 == 0){
        P2 = P2 | 0x03;
        Tmr1 = 0;
        }
if (Input2 == 0){
        P2 = P2 | 0x18;
        Tmr2 = 0;
        }
if (Input3 == 0){
        P2 = P2 | 0xC0;
        Tmr3 = 0;
        }
TI = 0;
SBUF = P2;
while (TI == 0);        /* Wait For Transmit */
if (TF0 == 1) {
        Tmr1 = Tmr1 + 1;
        Tmr2 = Tmr2 + 1;
        Tmr3 = Tmr3 + 1;
        if ((Tmr1>912)&&(Tmr2>912)&&(Tmr3>912)) {
                Tmr1 = 0;
                Tmr2 = 0;
                Tmr3 = 0;
                TR0 = 0;
                TF0 = 0;
                P2 = 0x00;
                }
        else if (Tmr1 == 912) {/* 60 Sec Alarm Hold*/
                P2 = P2 & 0xFC;
                }
        else if (Tmr2 == 912) {/* 60 Sec Alarm Hold*/
                P2 = P2 & 0xE7;
                }
        else if (Tmr3 == 912) {/* 60 Sec Alarm Hold*/
                P2 = P2 & 0x3F;
                }
        else {
                TH0 = 0xFF;
                TL0 = 0xFF;
                TF0 = 0;
                }
        }
}


void main() {

SCON = 0x40; /* 8-bit UART, BaudRate set by Timer-1 */
TMOD = 0x21; /* Timer1 mode 2, Timer-0 mode 1 */
TCON = 0x40; /* Start baud clock */
TR0 = 0;        /* Turn Timer-0 off */
TH0 = 0xFF;
TL0 = 0xFF;
TF0 = 0;        /* Clear rollover flag */
TR0 = 0;        /* Turn timer-0 on */
TH1 = 0xCC;     /* 600 baud 12MHz */
IE = 0x00;      /* Disable serial int */
IP = 0x80;      /* Interrupt priority stopped */
P2 = 0x00;
P3 = 0x00;
Input1 = 1;
Input2 = 1;
Input3 = 1;

while(1) {
  while ((Input1 == 1)&&(Input2 == 1)&&(Input3 == 1)) {
     TI = 0;
     SBUF = 0x00;
     while (TI == 0);/* Wait For Transmit */
     }
     TH0 = 0xFF;
     TL0 = 0xFF;
     TR0 = 1;            /* Turn timer-0 on */
     while (TR0 == 1) SendStatus();
     }
}

Parents
  • 0 in reply to Nir boh

    Is "Nir Bohadana" the same person as "Nir boh" - who started this thread?

    Your code is almost certainly doomed to failure:

    while(1){
   ACC = 0x00;
   if (Input1 == 0) {
        ACC = 0x01;
        }
   if (Input2 == 0) {
        ACC =ACC | 0x02;
        }
   if (Input3 == 0) {
        ACC =ACC | 0x04;
        }
   TxOK = 1;
   SBUF = ACC ;
   while(TxOK);
   }
}

    In a high-level language such as 'C', you simmply cannot rely upon any processor register such as ACC retaining its value across statements.

    So your first step must be to rewrite this properly in 'C' using a local variable to store your intermediate values...

Reply
  • 0 in reply to Nir boh

    Is "Nir Bohadana" the same person as "Nir boh" - who started this thread?

    Your code is almost certainly doomed to failure:

    while(1){
   ACC = 0x00;
   if (Input1 == 0) {
        ACC = 0x01;
        }
   if (Input2 == 0) {
        ACC =ACC | 0x02;
        }
   if (Input3 == 0) {
        ACC =ACC | 0x04;
        }
   TxOK = 1;
   SBUF = ACC ;
   while(TxOK);
   }
}

    In a high-level language such as 'C', you simmply cannot rely upon any processor register such as ACC retaining its value across statements.

    So your first step must be to rewrite this properly in 'C' using a local variable to store your intermediate values...

Children
  • 0 in reply to Andy Neil

    yes i'm the same person.

    OK, i'll try this in a couple of minutes.

    thanks.

  • 0 in reply to Nir boh

    can you write the line for me that
    declare a local variable to store the bits before sending them to the SBUF.

    i'm confused with unsign char ,char ....

  • 0 in reply to Nir boh

    "i'm confused with unsign char ,char ...."

    What, specifically, is the confusion?

    Sounds like you need a 'C' textbook?

    http://www.keil.com/books/

  • 0 in reply to Andy Neil

    that is waaaay too 'politically correct'

    Erik

  • 0 in reply to Andy Neil

    i changed my program, and still i found some
    odd things..

    the result are as this

    send >expected output> alternate output
    1...........0x01..............0x40
    2...........0x02..............0x20
    3...........0x03..............0xA0
    4...........0x04..............0x10
    5...........0x05..............0x50
    6...........0x06..............0x90
    7...........0x07..............0xB0

    the alternate output accures when i
    trigger the input bit again.

    #include <Reg51.h>

sbit Input1 = 0xB3;  /* P3.3 (INT1) bit set, Input 1 */
sbit Input2 = 0xB4;  /* P3.4 (T0)   bit set, Input 2 */
sbit Input3 = 0xB5;  /* P3.5 (T1)   bit set, Input 3 */

unsigned char TxOK = 0;
unsigned char xt = 0;

void serial_IT(void) interrupt 4
{
  if (TI == 1) {
    TI = 0;
    TxOK = 0;
    }
}

/* ~~~~~~~~~~ */
/*   Main Sub */
/* ~~~~~~~~~~ */
void main(){
SCON = 0x40;
TMOD = 0x20;
TR0 = 0;
TCON = 0x40;
TH1 = 0xCC;
TL1 = 0x00;
ES = 1;
EA = 1;

TxOK = 1;
TI = 1;
while(TxOK);

while(1){
if (Input1 == 0) {
        xt = 1;
        if (Input2 == 0) {
          xt = 3;
          if (Input3 == 0) {
             xt = 6;
             }
          }
        else if (Input3 == 0) {
          xt = 4;
          }
        }
else if (Input2 == 0) {
        xt = 2;
        if (Input3 == 0) {
          xt = 5;
          }
        }
else if (Input3 == 0) {
        xt = 7;
        }
else xt = 0;

TxOK = 1;
SBUF = xt;
while(TxOK);
}
}