12f675_fuse_about_to_blow!

[mackrackit]

The basic interrupt routine you have worked with

    DISABLE
    TLOOP:
    'DO SOMETHING
    INTCON.2=0
    RESUME
    ENABLE

SOMETHING...
I = I + 1
IF ??? THEN
???
RESET COUNTER
ENDIF

Tick Tock...

[LEDave]

DISABLE 
TLOOP:
IF INTCON.2=1 THEN I = I + 1 :INTCON.2=0 IF I<=100 GOTO MAIN IF I =100 GOTO TOG
 tog:TOGGLE GPIO.2
 RESUME: ENABLE

That's what I was trying to fit in.

Blimmey, it's nearly Friday already

Am I close-ish.

Dave

[mackrackit]

Close-ish...

IF INTCON.2=1
is not needed in the interrupt routine, that is what send the code there in the first place.

The rest might work.
Does it??

[LEDave]

Mmmm.

I was trying to use then reset IF INTCON.2=1 to increment count on 'I' the VAR.

IF INTCON.2=1 THEN I = I + 1 :INTCON.2=0

I'll sleep on it (I hope it doesn't keep me awake thinking).

Dave

[mackrackit]

Something...
I = I + 1
if ??? Then
???
I = 0 'reset counter
endif

[HenrikOlsson]

IF INTCON.2=1
is not needed in the interrupt routine, that is what send the code there in the first place.

Correct. But remember that if/when you start adding more interrupt sources you need to determine which one it was that tripped so checking the interrupt flag is probably good practice. But as have been said, it's not strictly needed in this case.

You seem to have a GOTO Main inside the ISR - you can do that but it is probably not a good idea as it will restart from the beginning of the program and not where it got interrupted. This MAY not be a problem in THIS particular program but can cause some interesting results so - try not to do that.

Have a look at this:

DISABLE 
TLOOP:
IF INTCON.2 = 1 THEN    'TMR0 Interrupt?
   I = I + 1            'Increment counter
   IF I = 100 THEN      'Has it reached 100?
      TOGGLE GPIO.2     'If so, toggle LED...
      I = 0             '...and reset counter
   ENDIF
   INTCON.2 = 0            'Reset interrupt flag
ENDIF
RESUME                  'back to work.
ENABLE

/Henrik.

[LEDave]

Well once again I've learned a lot of things, thanks as ever.

In the UK there's a famous comedy sketch where a musician says "I was playing all the right notes
but not necessarily in the right order".

I was a little (ok a lot) like that in this last exercise. I had written down I = 0 to reset the counter, I knew
I had to do that which is something and I'd figured I = I + 1 to add to / increment the counter, so not all bad.

Henrik highlighted within the program:

 INTCON.2 = 1 THEN   'TMR0 Interrupt?

I guess that's because as mackrackit pointed out to me that for the program to be there the INTERRUPT
must have already occured?

ANSEL   = %00000000      'Disable analog select so ports work as digital i/o
 CMCON0 = %00000111      'Disable analog comparators
 TRISIO = %11111110      'TRISIO.0 set as OUTPUT
 GPIO   = %00000000      'All bits set LOW
 INTCON.5 = 1            'ENABLE TMR0
 OPTION_REG = %10000101  '16BIT 1:64 PRESCALE
 

 ON INTERRUPT GOTO TLOOP  'ON INTERRUPT GOTO the INTERRUPT handler LABEL 'TLOOP'
                              
 i var byte               'Set I as a VARIABLE BYTE

Main: 
 
Not_pressed:
PAUSE 25                            'Leave 25mili_sec for a button press to occur.
if GPIO.5 = 1 THEN GOTO Not_pressed 'Keep waiting for +0v button press on GPIO.5
IF GPIO.5 = 0  THEN goto LED        'Button has been pressed move to LABEL LED:
LED:
TOGGLE GPIO.0                       'Change state of GPIO.0 pin
GOTO Not_pressed                    'Start again
 
 DISABLE                            'Disable INTERRUPT in handler
 TLOOP:
 IF INTCON.2 = 1 THEN   'TMR0 Interrupt?
   I = I + 1            'Increment counter
   IF I = 100 THEN      'Has it reached 100?
      TOGGLE GPIO.2     'If so, toggle LED...
      I = 0             '...and reset counter
   ENDIF
   INTCON.2 = 0         'Reset interrupt flag
ENDIF
RESUME:ENABLE           'ENABLE INTERRUPT in handler start prog again

10/10 for you guys.

Dave (not clever just persistent).