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printf() not working , peculiar situation ,

soumendra satapathy

dear friends i have a peculiar situation at hand . i am trying to dump some message to my serial port and see it through my dummy terminal . before that i tried a simple LED toggling , it worked fine .
for that the code i had written is :
#pragma small
#include<AT89X51.h>
#include<stdio.h>

int main()
{
TMOD = 0x20; // The timer set to 8 bit auto reload timer
TH1 = 0xFD; // Higher byte of timer1 set to FD or reload value set to FD
TL1 = 0xFD; // Lower byte of timer1 set to FD
SCON = 0x52; // The serial Controller is configured
TR1=1; // Timer 1 run flag set

while(1)
{
printf("Hello World \n"); // data sent to serial port for displaying



}

return 1 ;
}


so the problem is that on my hyperterminal i dont get anything . but in debug window ,in the serial watch window , i am able to see the output . but after burning the code into the chip and subsequently in the hyperterminal i am not able to .
i am not able to follow where lies the problem . in the c51 primer exact code has been given , but that too does not work .
plz help .ASAP
with regards
Som

Parents
  • 0 in reply to Dejan Durdenic

    hi dejan, thanx for replying .your question is good. my oscillator frequency is 11.0592 mhz, and the baud rate is 9600 bps as is evident on the code . the hyperterminal has been set at the same frequency i.e 9600 bps . an interesting thing is that , with the same hardware i am able to get on my hyperterminal output when i use assembly code(given below). just try if you can solve my problem . is there any setting on the simulator /complier / Hex file that i am missing out ???

    code:

    cseg at 0000H
    org 0000h
    ajmp start

    org 0040H

    start: mov sp,#40H
    mov r0,#07Fh
    back: mov @r0,#00
    djnz r0,back
    mov th1,#0FDh ;configure serial port as 9600/8bit/No
    mov tmod,#00100000b
    setb tr1
    mov scon,#50h ;

    repeat1:
    mov a,#'@'
    call _xmit_byte
    jmp repeat1

    ;----------------------------------------------------------------
    _XMIT_BYTE: MOV SBUF,A ;
    JNB TI,$ ;wait till byte is transmitted
    CLR TI ;
    RET
    ;----------------------------------------------------------------
    end

Reply
  • 0 in reply to Dejan Durdenic

    hi dejan, thanx for replying .your question is good. my oscillator frequency is 11.0592 mhz, and the baud rate is 9600 bps as is evident on the code . the hyperterminal has been set at the same frequency i.e 9600 bps . an interesting thing is that , with the same hardware i am able to get on my hyperterminal output when i use assembly code(given below). just try if you can solve my problem . is there any setting on the simulator /complier / Hex file that i am missing out ???

    code:

    cseg at 0000H
    org 0000h
    ajmp start

    org 0040H

    start: mov sp,#40H
    mov r0,#07Fh
    back: mov @r0,#00
    djnz r0,back
    mov th1,#0FDh ;configure serial port as 9600/8bit/No
    mov tmod,#00100000b
    setb tr1
    mov scon,#50h ;

    repeat1:
    mov a,#'@'
    call _xmit_byte
    jmp repeat1

    ;----------------------------------------------------------------
    _XMIT_BYTE: MOV SBUF,A ;
    JNB TI,$ ;wait till byte is transmitted
    CLR TI ;
    RET
    ;----------------------------------------------------------------
    end

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