Do PICs goto sleep?

[Tissy]

I have a small developmement which uses a PIC18F2550 (for later USB integration). At the moment, it takes 3 inputs from an RF module and depending on what button is pushed on the fob, jumps to a certain routine.

The only problem is that it works for about a minute, then doesn't.

If there is no activity, does the PIC goto sleep as such. I haven't come across this before if it does !!


Here is my code:

Clear
Define OSC 20          
'Define LOADER_USED 1
CMCON = 7 'disable comparators

' -----[ I/O Definition ]-----------------------------------------

TRISA = %11111111	' Set PORTA to all input
TRISB = %10000001   ' Set PORTB (0)INPUT (1-5)OUTPUTS
TRISC = %11111111	' Set PORTC to all input
PORTB = 0


' ----- System Outputs -----
Red     VAR PORTB.1     ' All LEDs connected
                        ' between RC pins and
                        ' ground via resistor
                        
' ----- System Inputs -----
SW1         Var PORTC.0
SW2         Var PORTC.1
SW3         Var PORTC.2


' -----[ Variable Definitions ]-----------------------------------
Loop        Var Byte
MaskSwitch  Var Byte

Gosub Ready

' ************************************************************
' *                   Main Program Section                   *
' ************************************************************

Main:
    MaskSwitch=PORTC & $07
        Select Case MaskSwitch
          Case 1 '%00000001 or SW1
            Gosub Procedure_SW1

          Case 2 '%00000010 or SW2
            Gosub Procedure_SW2

          Case 4 '%00000100 or SW3
            Gosub Procedure_SW3
    End Select
Goto Main


Ready:
    For Loop = 1 to 5
        Red = 1
        Pause 50
        Red = 0
        Pause 50
    Next Loop
Return


Procedure_SW1:
    Pause 10000 ' 20 second delay
    For Loop = 1 to 5
        Red = 1
        Pause 100
        Red = 0
        Pause 100
    Next Loop
Return

Procedure_SW2:
    red = 1
    pause 5000
    red = 0
Return

Procedure_SW3:
    for loop = 1 to 5
        red = 1
        pause 125
        red = 0
        pause 250
        red = 1
        pause 125
        red = 0
        pause 250
    next loop
Return

If you disconnect the power and then straight away reconnect, its still in a locked state. You have to remove power, wait about 8 seconds and then reconnect and all is fine, for a little while anyway! Most strange.

Thank you

[Ingvar]

I've never heard of any PICs going to sleep without beeing told so(they're just like kids ... and me), however i've never used this particular one. My guess is that your RF module gives out combinations that won't get caught by your SELECT CASE statement(0,3,5,6,7). Easily checked by adding CASE ELSE

/Ingvar

[Tissy]

Its not the RF module as the program works fine for the first minute or so.

Also, all the hybrid RF module does is output a HIGH or a LOW on three ports which are fed into the PIC. So all the PIC is reading is a 1 or a 0.

Any other suggestions,

Steve

[J_Brittian]

Is MaskSwitch ending up outside your parameters? What happens if you add a case else statement?

[Tissy]

Hmm, got me thinking now.

If i only wanted to look at RC0 , RC1 & RC2, i have now changed the TRISC to read:

TRISC = %00000111	' Set PORTC (0-2 input) rest Outputs

Is this correct?

Also, would any change need to be done for this line? What does the $07 mean?

MaskSwitch=PORTC & $07

What would you suggest i put in the CASE ELSE statement. A return back to Main? It may be worth puttin in this statement to capture any other event.

Thank you.

[J_Brittian]

Actually I was going to suggest an output of some kind, maybe an led. If MaskSwitch gets outside of your parameters in someway you could effectively end up in a main ... goto main loop.

[Tissy]

OK, I've added the following

Main:
    MaskSwitch=PORTC & $07
        Select Case MaskSwitch
          Case 1 '%00000001 or SW1
            Gosub Procedure_SW1

          Case 2 '%00000010 or SW2
            Gosub Procedure_SW2

          Case 4 '%00000100 or SW3
            Gosub Procedure_SW3
          Case Else
            Gosub Error
    End Select
Goto Main

Error:
    For loop = 1 to 5
        Red = 1
        Pause 100
        Red = 0
        Pause 100
    Next Loop
Return

Now the LED is flashing all the time, so i presume the CASE ELSE is true, which i guess means something else is happening.

I think it may be due to the following:

MaskSwitch=PORTC & $07

What does the $07 represent. Is this saying all of the PORTS on C. If so, what will it be if i want just PORTC.0, PORTC.1 and PORTC.2.

Thank you, i think i'm getting there!!

[Dwayne]

I agree with IngVar,

You have no way of knowing if the case statement is something other than 1,2,4. Put a default case in there with a blinking light....If that blinking light comes on... there is your problem.

Dwayne

[Tissy]

Dwayne,

Is what i've done above your posting wrong then? If so, could you post the modification to the code you are suggesting.

Many thanks.

[J_Brittian]

$07 = %00000111

Steve,
If you push two buttons at the same time or if you're not using pull down/up resistors you end up with MaskSwitch = %00000110 which isn't an option.

[Tissy]

Bugger, i think it might be due to no pull-down resistors.

I've attahced my circuit, would this be the case?

What values are recommended ?

Hopefully that is the problem which is reasonably easy to fix.

Regards,

Steve

[J_Brittian]

Try 5K. Hopefully that fixes your problem.

[Tissy]

The pull-down resistors didn't make any difference, the LED keeps in the 'error' flash routine. I didn't have and 5K, so i used a 2k2, would this still perform the task? If not i have 47k?

However, i have inserted:

Main:
    MaskSwitch=PORTC & $07
        Select Case MaskSwitch
          Case 1 '%00000001 or SW1
            Gosub Procedure_SW1

          Case 2 '%00000010 or SW2
            Gosub Procedure_SW2

          Case 4 '%00000100 or SW3
            Gosub Procedure_SW3
          Case Else
            Goto Main
    End Select
Goto Main

Adding the Goto Main routine now seems to work.

Although this is a work around, its still strange that some other signal is being received into the PIC which i would like to find.

Cheers.

[Ingvar]

After looking at the HiRK-433 datasheet(assuming this is the one you use http://www.okwelectronics.com/datasheets/DS.0010-2.pdf ), i say that there is no need for pulldowns(or ups). Just make sure your JP1 and 2 are not linked. This would make the outputs latching, you want them to be momentary.

/Ingvar

[Tissy]

Yup, thats the exact one.

Ok, i'll remove the pull-down resistors.

It must be something else that is making the CASE ELSE statement true then.

Cheers,

Steve

[arniepj]

When I am developing a project I always have a serial port available ,even if the project will not use it.Being able to check variables and ports is invaluable for debugging,versus debugging blind.

[Tissy]

OK, i'm ready for a slap !!

I failed to put a pull-up on the MCLR port. The thing is, i put it on my diagram, but failed to put it on the vero circuit.

Thanks again to all those that helped. I did solve another a couple of issues at the same time. So all was not wasted.

Regards,

Steve

[Ingvar]

Here comes the ruler ......... Nah, that's to easy on somebody who forgot something as serious as a pullup on MCLR. It's time for Melanie to get into her leather outfit and teatch you real good, that way it'll surely never happen again. It might, however, make me want to forget all about resistors .... and their proper use