Serin timeout not working properly!

[Bruce]

Sounds like it's working exactly like it should be.

1. TMR1 interrupts while it's sitting in your SERIN routine waiting for 3 ASCII characters
followed by the byte that gets placed in code (which by the way hasn't been declared).

2. Once the interrupt service routine executes, it returns right back to your SERIN
routine with the LED off.

Insert a toggle command in your int handler for a quick visual indication of the int handler
executing. That would tell you it's working or not.

And -as-is, it's never going to execute any code below your SERIN routine unless all 3 ASCII
characters + the byte that goes into your undeclared code VAR are received.

[Megahertz]

Hi Bruce, I did that and yes you are right (as always) about it. I Learnt a bit more about interrupts as well while dealing with this problem.

Can you please advise/explain me how can I make the code jump and move to the next line of Serin with help of Interrupts. I really appreciate your help.
Thanks


P.S: This is not the full code, all variables are declared in my code. I just tried to highlight the problem to you with minimum code here.

[Darrel Taylor]

I don't know if this is what you had in mind,
but it could be a possibility for your Timeout wishes.

With the extra features of the 12F635, you should be able to to create a WDT based timeout for the SERIN or other command(s).

Starting with the WDT turned off, and DEFINE NO_CLRWDT 1
And this un-tested code ... (don't have a 12F635)

DEFINE  OSC     4                   ' OSCCON defaults to 4MHz on reset
DEFINE  NO_CLRWDT 1                 ' stop kicking the DOG 

ASM
CFG =       _INTRC_OSC_NOCLKOUT     ; Oscillator
CFG=CFG&    _WDT_OFF                ; Watch Dog Timer <-- Very Important
CFG=CFG&    _PWRTE_ON               ; Power-on Timer
CFG=CFG&    _MCLRE_OFF              ; Master Clear Reset
CFG=CFG&    _BOD_OFF                ; Brown-out Detect
CFG=CFG&    _IESO_OFF               ; Internal External Switchover
CFG=CFG&    _FCMEN_ON               ; Fail-Safe Clock Monitor
CFG=CFG&    _WUREN_OFF              ; Wake-up and Reset
CFG=CFG&    _CP_OFF                 ; Code Protect
CFG=CFG&    _CPD_OFF                ; EEPROM Data Protect
  __CONFIG  CFG
ENDASM

INCLUDE "modedefs.bas"

'----[Pin Definations]------------------------------------------------------
LED1        VAR GPIO.0
LED2        VAR GPIO.1
ToTx  	    VAR GPIO.2     
ToRx        VAR GPIO.3
Monitor     VAR GPIO.4

;----[Variables/Aliases]----------------------------------------------------
TOaddr      VAR WORD BANK0 SYSTEM
code        VAR BYTE

WDTO        VAR STATUS.4                ; WatchDog Timer Timeout bit
SWDTEN     VAR WDTCON.0                 ; Software WDT Enable
BAUD        CON N2400

'----[Initialize]-----------------------------------------------------------
Init:
    IF !WDTO THEN                       ; If the WDT timed out
      TOGGLE LED2
      ASM
        movf    TOaddr + 1, W           ; Goto Timeout Address
        movwf   PCLATH
        movf    TOaddr, W               
        movwf   PCL
      ENDASM
    ELSE                                ; Power-on, or other Reset
        CMCON0 = 7              
        GPIO=0			       
        OPTION_REG = %00000111  
        WDA.4=1  : WPUDA.4=1
        WDTCON = %00010110              ; 1:65536, WDT off
    ENDIF

;----[Main Program Loop]----------------------------------------------------
Main:
    TOGGLE LED1
    ASM
        movlw  LOW(_TimeOut1)           ; Set the Timeout jump Address
        movwf  TOaddr
        movlw  HIGH(_TimeOut1)
        movwf  TOaddr + 1
        CLRWDT                          ; kick the DOG first
    ENDASM

    SWDTEN = 1                          ' enable the WDT
    Serin ToRx, BAUD,["pp3"],code
    SWDTEN = 0                          ' disable the WDT
       
    SELECT CASE code                    ' CHECK VALUES FOR THE RECEIVED CODE
      CASE 0                            '   Null code, no action
      
      CASE 1
          ; do code 1 
          
      CASE ELSE                         ' Unknown Code
          ; don't know the code. Ignore or Warn
    END SELECT
  GOTO Main

TimeOut1:                               ' Timeout occured
    SWDTEN = 0                          ' disable the WTD
    ; notify user of timeout
    ;   or do timeout cleanup
GOTO Main

Prior to starting a SERIN command, it saves an address to the Timeout1 Label and starts the WDT.

If the WDT times out during the SERIN command, the processor will RESET.

At the top of the program, it checks to see if the reset was from power-up, or the WDT. If it was from the WDT, it was a Timeout, so it jumps to the timeout label that was saved prior to starting the SERIN command.

All previous Stack levels are discarded. So the label that it jumps to MUST be in the Main loop.

Timeout period can be adjusted by changing the WDTCON prescaler.

Food for thought while drinking Champaigne.
Happy New Year!

[Megahertz]

Thanks Darell, it is very interesting how you can go around things in programming.
Is it possible you can provide PBP statements for the following lines of the code:

1) TOaddr      VAR WORD BANK0 SYSTEM

2) ASM
        movf    TOaddr + 1, W           ; Goto Timeout Address
        movwf   PCLATH
        movf    TOaddr, W               
        movwf   PCL
      ENDASM

3) ASM
        movlw  LOW(_TimeOut1)           ; Set the Timeout jump Address
        movwf  TOaddr
        movlw  HIGH(_TimeOut1)
        movwf  TOaddr + 1
        CLRWDT                          ; kick the DOG first
    ENDASM

Also I wonder if similar way of using WDT can be adopted for 12c671/12F508/16F676 as I have few little projects pending involving these and all of them will have one thing common - A noisy RF receiver attached to one pin

Thanks

P.S - No problem if you have not tested the code. I will try to my best to do it first, just after I know the PBP equivalent of the above statements.

[Darrel Taylor]

1) is already a PBP statement.

2) If you really must ... could be changed to ...

PCLATH = TOaddr.HighByte
PCL = TOaddr.LowByte

3) Must stay exactly like it is in ASM.

With the 12c671/12F508/16F676's, the WDT can not be turned on and off in software.
So this approach will not work with those chips.
<br>

[Megahertz]

So this approach will not work with those chips.
<br>

Thanks for the info, please advise me as to what other possible techniques there are for solving this problem with these other chips?
Thanks

[Darrel Taylor]

The best way is to use PIC's that fit your task.
Don't try to make your task work in a PIC that doesn't have the features you need.

Buy more 12F635's, they're only a buck apiece.
_____________
DT