Post by thread:[PIC]: 18C452 Watchdog Timer

Hi, After several posts during the last few weeks, I have discovered that either setting the watchdog to off in my chip programmer does not work, or else the code is re-enabling it. I am using the MPLAB C18 compiler, (writing my code in C) and would like to turn off this configuration bit at the beginning of my program. Could anyone give some advice on how to disable the WDT enable bit in C? Can I insert an assembly routine to disable it? ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender immediately. This footnote also confirms that this email message has been swept by MIMEsweeper and Symantec Norton AntiVirus for the presence of computer viruses. ********************************************************************** -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> Could anyone give some advice on how to disable the WDT enable > bit in C? WDTCONbits.SWDTEN = 0; Remember also if you are using an ICE, that you should disable the WDT in your program AND in the configuration tab of 'development mode' in MPLAB. Regards, Carlos Ojea -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> Can I insert an assembly routine to disable it? No, this can't be done at run time. The watchdog timer is enabled/disabled in the configuration word. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

The watchdog enable bit is in the config register and it cannot be changed by code. C18 may have a #pragma to set config bits. Alternatively MPLAB will let you set up the config you want. Finally, if you use PICSTART / ProMate, etc you can tweak the config just before you burn the chip. Bob Ammerman RAm Systems {Original Message removed}

>> Can I insert an assembly routine to disable it? > >No, this can't be done at run time. The watchdog timer is enabled/disabled >in the configuration word. For pic18 the SWDTEN bit of WDTCON register enables/disables the operation of the WDT, but ONLY WHEN the WDT configuration bit is cleared. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Thu, Jul 18, 2002 at 10:47:46AM -0400, Bob Ammerman wrote: > The watchdog enable bit is in the config register and it cannot be changed > by code. Maybe James should consider switching to the 18F452. It does have a software WDT bit that is controllable via code. BAJ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Thu, Jul 18, 2002 at 05:06:28PM +0200, Carlos Ojea wrote: > >> Can I insert an assembly routine to disable it? > > > >No, this can't be done at run time. The watchdog timer is enabled/disabled > >in the configuration word. > > > > For pic18 the SWDTEN bit of WDTCON register enables/disables the operation > of the WDT, but ONLY WHEN the WDT configuration bit is cleared. But is that for the PIC18C452 parts too? I know that's true for the flash parts, but does it somehow apply to the EPROM based 18C parts also? BAJ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

>> For pic18 the SWDTEN bit of WDTCON register enables/disables the operation >> of the WDT, but ONLY WHEN the WDT configuration bit is cleared. > >But is that for the PIC18C452 parts too? I know that's true for the flash >parts, but does it somehow apply to the EPROM based 18C parts also? Yes, that's true also for 18C parts. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.