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Why does my program always start from C:0x00AE?

Liu Rinfen

Dear all,

Thank you for your help in advance.

I created a very simple program to test my Monitor-51 which is showed below:

#include "AT89X55.H"

sbit P25 = 0xA5;

void DELAY(int j)
{
 int i;
 for(;j>0;j--)
  {
   for(i=2;i>0;i--)
    {;}
  }
}

main(){
while(1)
    {
    P25 = 0;
    DELAY(1);
    P25 = 1;
    DELAY(1);
    }
}

When I debugged this program by using Monitor-51,the first line is always "C:0x0000 0200AE LJMP c:00AE" in
the Disassembly window,and the other lines are:
...
C:0x00AE    E4       CLR      A
C:0x00AF    F5CB     MOV      RCAP2H(0xCB),A
C:0x00B1    F5CA     MOV      RCAP2L(0xCA),A
C:0x00B3    F5CC     MOV      TL2(0xCC),A
C:0x00B5    F5CD     MOV      TH2(0xCD),A
C:0x00B7    F5C9     MOV      T2MOD(0xC9),A
C:0x00B9    F5C8     MOV      T2CON(0xC8),A
C:0x00BB    20B0FD   JB       RXD(0xB0.0),C:00BB
C:0x00BE    30B0FD   JNB      RXD(0xB0.0),C:00BE
C:0x00C1    D2CA     SETB     TR2(0xC8.2)
C:0x00C3    30B003   JNB      RXD(0xB0.0),C:00C9
C:0x00C6    30CFFA   JNB      TF2(0xC8.7),C:00C3
C:0x00C9    30B0FD   JNB      RXD(0xB0.0),C:00C9
C:0x00CC    30B003   JNB      RXD(0xB0.0),C:00D2
C:0x00CF    30CFFA   JNB      TF2(0xC8.7),C:00CC
C:0x00D2    30B0FD   JNB      RXD(0xB0.0),C:00D2
C:0x00D5    C2CA     CLR      TR2(0xC8.2)
C:0x00D7    20CFD4   JB       TF2(0xC8.7),C:00AE
C:0x00DA    AFCC     MOV      R7,TL2(0xCC)
C:0x00DC    AECD     MOV      R6,TH2(0xCD)
C:0x00DE    EE       MOV      A,R6
C:0x00DF    C3       CLR      C
...
And I failed to change the statement by use of "Inline assembly".Why the assembly try to initial the timer2? I wonder if the MON51.HEX createad by INSTALL.A51 is fit to AT89S52? The MCU is AT89S52. I set the Option for target as follow: Off-chip code memory Start:0x8000, size:0x3fff, Off-chip Xdata memory Start:0xc000, size:0x3fff. When I use simulator to debug this program there is no problem. Can you give me a hand? Thanks.

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