Post by thread:Newbie code doesn't seem to work

Hi all. I've been playing with this bit of code for a few days now and I can't see what the problem is. Using RB0 the code should generate a morse signal as DIT - DAH - DIT - DAH - DIT - DAH reapeatedly. However I seem to be getting an extra DAH in there somewhere. I am getting DIT - DAH - DIT - DAH - DIT - DAH - DAH repeatedly. Looking at the code can anyone see a problem, or can i assume it is a hardware problem. I am using a P16F84 processor. Thanks Dan <CODE> PORTA EQU 0x05 PORTB EQU 0x06 TRISA EQU 0x85 TRISB EQU 0x86 STATUS EQU 0x03 DITLEN EQU 0x64 CNT1 EQU 0x30 DITCOUNT1 EQU 0X20 DITCOUNT2 EQU 0X21 DAHCOUNT1 EQU 0X22 ORG 0x00 GOTO START ONOFF MOVLW 1 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPONOFF1 DECFSZ CNT1 GOTO LOOPONOFF1 MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPONOFF2 DECFSZ CNT1 GOTO LOOPONOFF2 RETURN OFFOFF MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPOFFOFF1 DECFSZ CNT1 GOTO LOOPOFFOFF1 MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPOFFOFF2 DECFSZ CNT1 GOTO LOOPOFFOFF2 RETURN PLAYDIT MOVLW DITLEN MOVWF DITCOUNT1 PLAYDITLOOP CALL ONOFF DECFSZ DITCOUNT1 GOTO PLAYDITLOOP RETURN DITSPACE MOVLW DITLEN MOVWF DITCOUNT2 DITSPACELOOP CALL OFFOFF DECFSZ DITCOUNT2 GOTO DITSPACELOOP RETURN PLAYDAH MOVLW DITLEN MOVWF DAHCOUNT1 PLAYDAHLOOP CALL ONOFF CALL ONOFF CALL ONOFF DECFSZ DAHCOUNT1 GOTO PLAYDAHLOOP RETURN START BSF STATUS, 5 MOVLW 0 MOVWF TRISB BCF STATUS, 5 STARTLOOP CALL PLAYDIT CALL DITSPACE CALL PLAYDAH CALL DITSPACE END </CODE> ************************************************************************ Daniel Watford CCTEC Ltd. 23 Station Road Westgate KENT CT8 8RB UK Tel: +44 (0) 1843 833999 Fax: +44 (0) 1843 835999 Software Developer - Windows 95, 98, NT, Linux. spam_OUTdaniel.watfordTakeThisOuTcctec.ltd.uk ************************************************************************ How many programmers does it take to change a light bulb? They refuse. They say, "It's a hardware fault". -- Arthur Buse ************************************************************************

Daniel Watford wrote: > > Using RB0 the code should generate a morse signal as DIT - DAH - DIT - DAH - > DIT - DAH reapeatedly. However I seem to be getting an extra DAH in there > somewhere. I am getting DIT - DAH - DIT - DAH - DIT - DAH - DAH repeatedly. > STARTLOOP > CALL PLAYDIT > CALL DITSPACE > CALL PLAYDAH > CALL DITSPACE Maybe put GOTO STARTLOOP > > END > -- Best regards Tony 'The Engine' - Design your own programmer. http://www.picnpoke.com Email .....picnpokeKILLspam@spam@cdi.com.au

Hi all. I've been playing with this bit of code for a few days now and I can't see what the problem is. Using RB0 the code should generate a morse signal as DIT - DAH - DIT - DAH - DIT - DAH reapeatedly. However I seem to be getting an extra DAH in there somewhere. I am getting DIT - DAH - DIT - DAH - DIT - DAH - DAH repeatedly. Looking at the code can anyone see a problem, or can i assume it is a hardware problem. I am using a P16F84 processor. Thanks Dan <CODE> PORTA EQU 0x05 PORTB EQU 0x06 TRISA EQU 0x85 TRISB EQU 0x86 STATUS EQU 0x03 DITLEN EQU 0x64 CNT1 EQU 0x30 DITCOUNT1 EQU 0X20 DITCOUNT2 EQU 0X21 DAHCOUNT1 EQU 0X22 ORG 0x00 GOTO START ONOFF MOVLW 1 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPONOFF1 DECFSZ CNT1 GOTO LOOPONOFF1 MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPONOFF2 DECFSZ CNT1 GOTO LOOPONOFF2 RETURN OFFOFF MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPOFFOFF1 DECFSZ CNT1 GOTO LOOPOFFOFF1 MOVLW 0 MOVWF PORTB MOVLW 0xFF MOVWF CNT1 LOOPOFFOFF2 DECFSZ CNT1 GOTO LOOPOFFOFF2 RETURN PLAYDIT MOVLW DITLEN MOVWF DITCOUNT1 PLAYDITLOOP CALL ONOFF DECFSZ DITCOUNT1 GOTO PLAYDITLOOP RETURN DITSPACE MOVLW DITLEN MOVWF DITCOUNT2 DITSPACELOOP CALL OFFOFF DECFSZ DITCOUNT2 GOTO DITSPACELOOP RETURN PLAYDAH MOVLW DITLEN MOVWF DAHCOUNT1 PLAYDAHLOOP CALL ONOFF CALL ONOFF CALL ONOFF DECFSZ DAHCOUNT1 GOTO PLAYDAHLOOP RETURN START BSF STATUS, 5 MOVLW 0 MOVWF TRISB BCF STATUS, 5 STARTLOOP CALL PLAYDIT CALL DITSPACE CALL PLAYDAH CALL DITSPACE END </CODE> ************************************************************************ Daniel Watford CCTEC Ltd. 23 Station Road Westgate KENT CT8 8RB UK Tel: +44 (0) 1843 833999 Fax: +44 (0) 1843 835999 Software Developer - Windows 95, 98, NT, Linux. daniel.watfordKILLspamcctec.ltd.uk ************************************************************************ How many programmers does it take to change a light bulb? They refuse. They say, "It's a hardware fault". -- Arthur Buse ************************************************************************

> Van: Daniel Watford <.....piclistKILLspam.....CCTEC.LTD.UK> > Aan: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU > Onderwerp: Newbie code doesn't seem to work - please take a look > Datum: dinsdag 6 juli 1999 14:39 > > Hi all. Hello Daniel, > I've been playing with this bit of code for a few days now and I can't see > what the problem is. > > Using RB0 the code should generate a morse signal as DIT - DAH - DIT - DAH - > DIT - DAH reapeatedly. However I seem to be getting an extra DAH in there > somewhere. I am getting DIT - DAH - DIT - DAH - DIT - DAH - DAH repeatedly. > > Looking at the code can anyone see a problem, or can i assume it is a > hardware problem. <Snip> > STARTLOOP > CALL PLAYDIT > CALL DITSPACE > CALL PLAYDAH > CALL DITSPACE > > END As someone else allready pointed out, your program stops at the END directive, but the PIC's Program-counter does not. So it will continue into uncharted lands :-) Amazing that your program went into a loop ! Another thing: You _did_ disable the WachDog, did you ... <grin> Greetz, Rudy Wieser

> Van: Daniel Watford <@spam@piclistKILLspamCCTEC.LTD.UK> > Aan: KILLspamPICLISTKILLspamMITVMA.MIT.EDU > Onderwerp: Re: Newbie code doesn't seem to work - please take a look > Datum: donderdag 8 juli 1999 12:05 > > Hi again, Hello Daniel, > I've checked the watchdog timer, and indeed it was enabled. > I've now disabled it and the circuit is working perfectly. > What does the watchdog time do exactly? Wachdog-timers are invented to mess-up programs of Newbies. Really ! :-) Ah, well. Id see you don't beleive me. O.k. Another explanation of their existence: It is possible that a controller will get stuck in some kind of loop, due to bad programming (go kick the programmer :-) or due to power spikes and the like. When this happens, the circuit has to be reset to enable it to work again. So, the first controllers where build wid a LED attached, that blinked when all was well. If it stopped blinking, someone had to press the RESET button. After a while someone build a "missing puls" detector (a retriggerable mono-flop) and connected that to the blinking led and the RESET button. Now, whenever the led stopped blinking, the mono-flop would time-out, and reset the system. No human needed anymore ! Later they decided to build the mono-flop into the system. That feature is now known as a "WachDog". It will simply count pulses (from and independend internal source). If the WachDog-counter overflows it will either Reset the controller (or generate a Interrupt, depended on how it's configured). The blinking LED was replaced by an Instruction to re-set the WachDog (CLRWDT -> Clear WachDog Timer). So, when a WachDog is enabled and not re-set every once-in-a-while, it will eventually reset the controller, creating strange effects for unsuspecting Newbies .... (Sorry, could not let this one go ... :-) Greetz, Rudy Wieser

Hi Caisson, Just a quick message to say thanks for the explanation. It does sound that if used properly the watchdog timer can be a very usefull feature. Is it just a case that when using it you must issue the CLRWDT command. Thanks again Dan ************************************************************************ Daniel Watford CCTEC Ltd. 23 Station Road Westgate KENT CT8 8RB UK Tel: +44 (0) 1843 833999 Fax: +44 (0) 1843 835999 Software Developer - Windows 95, 98, NT, Linux. RemoveMEdaniel.watfordTakeThisOuTcctec.ltd.uk ************************************************************************ How many programmers does it take to change a light bulb? They refuse. They say, "It's a hardware fault". -- Arthur Buse ************************************************************************

Daniel Watford wrote: > > Hi Caisson, > > Just a quick message to say thanks for the explanation. > > It does sound that if used properly the watchdog timer can be a very usefull > feature. > Is it just a case that when using it you must issue the CLRWDT command. > > Thanks again > > Dan Watchdog Timer's pretty much mandatory on life-critical systems (On avionics, for example, you don't want a 747 crashing into the ground because your ground proximity warning system's been hung for the last 3 hours, due to a cosmic ray ionizing things & crashing your GroundProx system.) Wouldn't be good if the CPU in someone's pacemaker crashed, either... I prefer "Feed the dog" to "Kick the dog" which some people use when resetting the Watchdog Timer (Dogs're FAR happier when fed treats, then when kicked!) WDT isn't particularly necessary on LED blinkers & so on <G> Mark

> Van: Daniel Watford <spamBeGonepiclistspamBeGonecctec.ltd.uk> > Aan: TakeThisOuTPICLISTEraseMEspam_OUTMITVMA.MIT.EDU > CC: RemoveMEcaissonTakeThisOuTtelebyte.nl > Onderwerp: Re: Newbie code doesn't seem to work - please take a look (watchdog) > Datum: vrijdag 9 juli 1999 12:05 > > Hi Caisson, > > Just a quick message to say thanks for the explanation. You're welcome. > It does sound that if used properly the watchdog timer can be a very usefull > feature. It is ! > Is it just a case that when using it you must issue the CLRWDT command. No. You have to set-up the Wach-dog timer first. It must be enabled (in the configuration-word), and you can assign a pre-scaler to it, so that the time-out of the wachdog-timer can be extended. And you can define what an wachdog time-out does: Reset the device, or issue an interrupt. Default : No prescaler, reset the device (as you have noticed :-) Greetz, Rudy Wieser