How do I implement a software reset in my source program?

C51: Implementing Software Reset with C51
Q:
How can I implement software reset in my source program? 

A:
You can use the following program to jump to 0000H to implement soft reset. The following program is actually a function pointer, which points to the address 0000H.
((void (code *) (void)) 0x0000) ();

 

The following example will implement software self-reset void reset (void)
{
((void (code *) (void)) 0x0000) ();
}

void main (void)
{
reset ();
}


You may notice that the above soft reset program does not clear the 8051 interrupt system and some 8051 peripherals. When you call the above software reset program in the interrupt program, the interrupt will no longer be triggered. Therefore, the above soft reset program cannot be called in the interrupt subroutine. The following


small assembly function can be called in the interrupt program or the main program. The function pushes 0x0000 onto the stack and then pops it with "RETI". This will clear the interrupt environment and let the program restart from 0000H.

?PR?RESET SEGMENT CODE
RSEG ?PR?RESET

; C prototype: void reset (void);

PUBLIC reset
reset: POP ACC pop return address
       POP ACC
       CLR A push 0 as new
       PUSH ACC return address to stack
       PUSH ACC
       RETI execute return of interrupt

       END


The above program works well when bank 0 register group is selected. If the bank 0 register group is not selected, you may not get the expected results. You should add "MOV PSW, #0" in the above program or startup code to select bank 0 register group.