Toggle program branch ussing interrupot by button?

[Acetronics2]

with PBP "on interrupt" it looks this figure is covered in the manual @ $ 5.66 ( RESUME xxx ) : you can choose the "return" adress xxx as you want ... so LOOP2 always completes.

- also note if you do not clear the interrupt flag ( With a DEFINE ) you automatically re-enter the ISR when completed !

- For DT interrupts ... I didn't check if the resume address can be freely chosen ...

- last idea is simply to overwrite the interrupt return address on the stack ... ( with asm "push" and "pop" macros see midrange manual, interrupts chapter ), depending on the button state.

Alain

[CuriousOne]

I don't want to include the button status check routine in the loops, since whole program works with microsecond delays and high accuracy. This is why I wanted to use interrupt. LOOP1 and LOOP2 are totally independent tasks, they don't use same variables, timings or whatsoever.

[LinkMTech]

That's a good question...

I wonder if something like this would work?

x VAR BIT

;----------------------- Setup Interrupts --------------------------------
INCLUDE "DT_INTS-18.bas"     ; Darrel Taylor's Base Interrupt System
INCLUDE "ReEnterPBP-18.bas"  ; Include if using PBP interrupts
ASM
INT_LIST  macro ; IntSource,          Label,  Type, ResetFlag?
    INT_Handler    INT0_INT,     Button_ISR,   PBP,  yes
    
    endm
    INT_CREATE             ; Creates the interrupt processor
ENDASM

;----------------------[Initialise Interrupts]-----------------------
@   INT_ENABLE  INT0_INT         ; Enable Button interrupt input
x = 0       ' Clear button status flag bit

PAUSE 100
GOTO loop1  ' Start at loop1 routine

' ---------------- Independent program routines -------------------------
loop1_start:
@ INT_RETURN    ; Reset the ISR

loop1:
    ' Perform one type of "time critical" function
GOTO loop1


loop2_start:
@ INT_RETURN    ; Reset the ISR

loop2:
    ' Perform a different type of "time critical" function   
GOTO loop2

;--------------------[Program routine selector ISR]----------------------
; make sure button signal debounced

Button_ISR:    
    x = !x      ' Toggle x status flag bit
    
    IF !x THEN
        GOTO loop1_start    ' Go here when x=0
    ELSE 
        GOTO loop2-start    ' Go here when x=1
    
@ INT_RETURN

Like Henrick said, the routines could be cut short anytime the button is pushed though.

[CuriousOne]

Thanks. As I can see, the code is for PIC18xxx family. Will it work on 12xx or 16xx ?

[LinkMTech]

Not for PIC12's or 16's.
You'll have to download DT's Interrupts for them here and replace entry with:

INCLUDE "DT_INTS-14.bas"    ; Base Interrupt System
INCLUDE "ReEnterPBP.bas"    ; Include if using PBP interrupts

I was kinda hoping someone would point out my errors in my suggestion, if any, before you went too far into a possible dead end.

If you haven't tried DT's INTS, you're missing out on some awesome timing control when it comes to sequence of events. It took me a little while to understand but finally got some handle on it when I monitored two interrupts taking turns to run their routines, especially when one occurs while the other ISR is taking care of business.

[HenrikOlsson]

Hi,

I was kinda hoping someone would point out my errors in my suggestion, if any, before you went too far into a possible dead end.

Ok Louie, I'll take a stab at that if you wish... :-)

If the program is looping around in Loop2 (x=1) when the interrupt occurs the ISR will toggle x to 0 and then GOTO Loop1_Start.
At Loop1_Start there's an @INT_RETURN which will send it back into Loop2 since that's where it was when the interrupt occured.

/Henrik.

[LinkMTech]

Thanks Henrik, I stand corrected.

CuriousOne, I tried to do something like this in the past and thought I came up with a better idea all of a sudden, but to avail.

[CuriousOne]

I found a sample code here:

http://darreltaylor.com/DT_INTS-14/hello.html

The code is OK for me, since I also need a selected loop indication via led. What if I mod it a like this:

'---[INT - interrupt handler]---------------------------------------------------
ToggleLED1:
     TOGGLE LED1
IF LED1=1 then goto LOOP1 ELSE GOTO LOOP2

LOOP1:

LOOP2: 
@ INT_RETURN