Beginner in need of help !!

[HenrikOlsson]

Hi,
No debounce may very well be part of the problem but in THIS case I think the contact bounce is what actually makes it sort of "work".
The real issue, I believe, is that your "loops" looks for ModeFlag being equal to 1 and switches mode. But the flag is not being cleared. So, if you push the button once, the ISR sets the flag. If there are no bounce the flag will be set all the time and the program will keep cycling between the different modes since the flag is never cleared. That's a problem with the implementation.

What's more severe is that you're using GOSUB without a matching RETURN. What you want in this case is GOTO.

Make the ISR set (and only set) the ModeFlag, implement some debounce in the ISR.
In the main loop you check the ModeFlag and IF it's set you first clear it and then act accordingly (ie. jump to the next mode).

Also, there's no need to set the LED high or low 1000 times (ie do it inside the FOR_NEXT loop), one time is enough, I'd rewrite the loop like:

DO
    HIGH LED
    for loop1 = 1 to 1000
        pause 1    '1 ms
        IF ModeFlag = 1 THEN
          ModeFlag = 0
          GOTO Mode 2
        ENDIF    
     next loop1
    
    LOW LED 'led off
    for loop1 = 1 to 1000
        pause 1    '1 ms
        IF ModeFlag = 1 THEN
          ModeFlag = 0
          GOTO Mode 2
        ENDIF
    next loop1
LOOP

/Henrik.

[robbo78]

Hi Henrik, thanks for helping. I have changed to the code to do as you said: goto's instead of gosub's & made the ISR set flag only (i think).

It all seems to work better now, however I still have a problem with the debounce as I think it is actually 'the problem' now instead of actually making the code work as you stated. The isr sees the release of the button as an interrupt & sets a flag again which skips modes. So how do I go about adding the debounce without slowing things down?

Isnt there a way to only interrupt or tell the ISR to flag only if the button is depressed & not when released? Here is the updated code -

'PIC 12F683

#CONFIG 
   __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
#ENDCONFIG

'DEFINE OCS 4 '4mhz ocsillator
DEFINE OSC 4 '4mhz ocsillator
ANSEL = 0 'all I/O digital
CMCON0 = 7 'comparator off
LED VAR GPIO.0 'LED pin 7

loop1 var word  ' Loop 1 Counter (word for 0 to 65535 increments)
ModeFlag var bit   ' Bit to determine what state of IOC.3 is

'*****Initlaze Vars*****
   loop1 = 0
ModeFlag = 0
'***********************

ON INTERRUPT GOTO modeselect 'interrupt handler is modeselect
INTCON = %10001000 'enable GIE and GPIE; clear GPIF
IOC = %00001000 ' enable IOC3 (GPIO3 Interrupt on change)

ENABLE 
mode1:
do
    for loop1 = 1 to 1000
        HIGH LED 'led on
        'PAUSE 1000 'delay 1 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        ModeFlag = 0
        goTO mode2
    ENDIF
    
    next loop1
    
    for loop1 = 1 to 1000
        LOW LED 'led off
        'PAUSE 1000 'delay 1 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        Modeflag = 0
        goTO mode2
    endif
    
    next loop1

'GOTO mode1 'repeat
loop

ENABLE 
mode2:
do
    for loop1 = 1 to 500
        HIGH LED 'led on
        'PAUSE 500 'delay 0.5 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        modeflag = 0
        goTO mode3
    endif
    
    next loop1
    
    for loop1 = 1 to 500
        LOW LED 'led off
        'PAUSE 500 'delay 0.5 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        modeflag = 0
        goTO mode3
    endif
    
    next loop1

'GOTO mode2 'repeat
loop

ENABLE
mode3:
DO
    for loop1 = 1 to 50
        HIGH LED 'led on
        'PAUSE 50 'delay 0.05 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        modeflag = 0
        goTO mode1
    endif
    
    next loop1
    
    for loop1 = 1 to 50
        LOW LED 'led off
        'PAUSE 50 'delay 0.05 second
        pause 1    '1 ms
        if ModeFlag = 1 then
        modeflag = 0
        goTO mode1
    endif
    
    next loop1

'GOTO mode3 'repeat
loop
    
DISABLE 'disable interrupts in handler
modeselect:
if INTCON.0 = 1 then    'one of the GPIO<5:0> pins changed state (must be cleared in software)    
    'next mode

    'Set the ModeFlag
    ModeFlag = 1
    ENDIF
    
INTCON = %10001000  'enable GIE and GPIE; clear GPIF
RESUME 'return to where left off
ENABLE 'enable interrupts

end 'got here by mistake

[HenrikOlsson]

Hi,
You're quite right, it's because you're using the IOC (Interrupt On Change), it'll trip the interrupt both when you push the button and when you release the button. (As well as on all the edges of the contact bounce). Also, when you're using IOC you need to remember to read the port (even if you're not using the value) in order to clear the mismatch condition.

I'd wire the button to GP2 and use the "normal" INT instead of IOC.

/Henrik.

[robbo78]

So if I want to use IOC, I would need to read the button or any other type of input such as the adc?

I'm only asking as I need to be able to use interrupt on like 5 inputs, not just 1. Although gp2 will use adc not any others if that would be easier.

Thanks,
Rob

[HenrikOlsson]

Hi Rob,
The IOC trips the interrupt on any change of the state on a digital pin. An interrupt will trip when the pin goes low and again when the pin goes high - provided you read the state of the pin in between. So in the ISR you need to read the state of switch and determine if it was pushed or released (and don't forget about the contact bounce). If it's determined that the interrupt tripped because the button was released you don't set the MODEFLAG.

And, once again, the ADC can NOT generate an interrupt when the analog voltage on the input changes. It won't work with IOC. Any pin configured as analog input will always read '1' and will never trip the IOC or INT interrupts.
Depending on what you want to do you might be able to use the comparator, they can be setup to trip an interrupt when their respective output changes state.

/Henrik.

[robbo78]

Hi Henrik, thanks for explaining that it makes things a lot clearer as to how I'm going to run the code. What I would like to do is have one of the inputs (gp2), taking a reading from ADC every say 0.5 - 1 seconds.

Basically I want the chip to enter low power mode along with the device. When the device is off, one of the component pins goes to 0.00v, then when it is turned on it goes to 0.70v & stays at that. So I would like the ADC to monitor this, then when the voltage drops below 0.60v the chip is in low power mode, then when the voltage is higher than 0.60v I want it to come out of low power mode.

I hope this can be done in some way,
Rob

[Tabsoft]

Rob,

I don't think the ADC module will accomplish what you are attempting as Henrik stated in his last reply.
You should look into the Comparator of the PIC, again as Henrik suggested.

[robbo78]

Hi guys, okay I've been having a mess today & I am quite happy with myself. I managed to use the comparator successfully, now I have added a button into the routine.

It is all doing what I want it to but I am having this big issue with de-bouncing how do I sort this out, what is the best way? Do I need to read the button in a different way?

Here is the code -

'PIC 12F683

#CONFIG 
   __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
#ENDCONFIG


DEFINE OSC 4 '4mhz ocsillator
ANSEL = %00000001 'pin 7 analog
CMCON0 = %00011110 'comparator mode
VRCON = %10100000 'voltage reference
TRISIO = %00101111 'pin 2,4,5,6,7 input

PAUSE 50 'wait for hardware to settle

ON INTERRUPT GOTO int1 'interrupt handler is int1
INTCON = %11001000 'enable GIE and GPIE; clear GPIF
PIE1 = %00001000 'enable comparator interrupt
IOC = %00001000 'pin 3 ioc

RTPOT VAR CMCON0.6 'right trigger pot
RTBITTEST var bit 'trigger debug test bit. Set/Clear in ISR and Check in main

BUT VAR GPIO.3 'tactile button
BUTBITTEST VAR BIT 'button test bit


RTBITTEST = RTPOT 'initial reading

BUTBITTEST = 0 'read 0 to start


ENABLE
main:

IF RTBITTEST = 1 THEN
GOTO RAPID
ENDIF

IF RTBITTEST = 0 THEN
GOTO SLEEPY
ENDIF

GOTO main


ENABLE
RAPID:

LOW GPIO.0 
PAUSE 70
TRISIO.0 = 1 
PAUSE 70

IF RTBITTEST = 0 THEN
GOTO SLEEPY
ENDIF

IF BUTBITTEST = 1 THEN
GOTO FLASH
ENDIF

GOTO RAPID


ENABLE
SLEEPY:

HIGH GPIO.5
PAUSE 1000
TRISIO.5 = 1
PAUSE 1000

IF RTBITTEST = 1 THEN
GOTO main
ENDIF

GOTO SLEEPY


ENABLE
FLASH:

HIGH GPIO.5
PAUSE 300
TRISIO.5 = 1
PAUSE 300

IF BUTBITTEST = 1 THEN
GOTO RAPID
ENDIF

GOTO FLASH

  
    
DISABLE 'disable interrupts in handler
int1:
    
if PIR1.3 = 1 then  'Comparator Interrupt fired (must be cleared before resume)
RTBITTEST = RTPOT
ENDIF

IF IOC.3 = 1 THEN
BUTBITTEST = BUT
ENDIF 

INTCON =%11001000 
PIR1 = %00000000 'reset CMIF
IOC = %00000000 'reset IOC.3
RESUME 'resume to where left off
ENABLE 'enable interrupts

[Tabsoft]

Rob,
You really don't state what the problem is, only that you see a problem.

A quick scan of the code leads to too many questions for me.
What are you trying to accomplish in the different subroutines Rapid, Sleepy and Flash?
You seem to be using two GPIO pins, one for Rapid (GPIO.0) and another (GPIO.5) for Sleepy and Flash.
Another question is why in each of the subroutines are you setting the GPIO high, pausing and then configuring the same GPIO as an input?

Without more info, it is futile to offer an opinion.