Post by thread:Basic doubt on interrupts

hi everyone, This is about the basics on interrupts. Suppose my normal routine is getting interrupted say by interrupt on change(RB4), and goes to 0x04 and in ISR, I am forcing to goto some other location and further there is branching and it again comes back to the routine where interrupts are re-enabled. In any of the routine which branches from ISR,, there is no (call return ) and all are (goto). What would be the status of stack? Whether the stack will be over written and can this effect the program operation rams

: S.Ramasubramanian wrote: > Suppose my normal routine is getting interrupted say by interrupt on > change(RB4), and goes to 0x04 and in ISR, I am forcing to goto some > other location and further there is branching and it again comes back > to the routine where interrupts are re-enabled. In any of the routine > which branches from ISR,, there is no (call return ) and all are > (goto). What would be the status of stack? Three operations affect stack. Interrupt, CALL and return (including RETI = return from interrupt which is absolutely nothing more than an indivisible combination of a a subroutine return and setting the GIE flag). Branches do not, skips do not, operating on PCL does not. In all probability, reset (MCLR) does not as the stack is circular. -- Cheers, Paul B.

>hi everyone, >This is about the basics on interrupts. Suppose my normal routine is >getting interrupted say by interrupt on change(RB4), and goes to 0x04 and >in ISR, I am forcing to goto some other location and further there is >branching and it again comes back to the routine where interrupts are >re-enabled. In any of the routine which branches from ISR,, there is no >(call return ) and all are (goto). What would be the status of stack? >Whether the stack will be over written and can this effect the program >operation > >rams > Check out my comments last week in the "Reset" thread here on piclist. - Dan Michaels Oricom Technologies http://www.sni.net/~oricom ==========================