Post by thread:PIC16C74 Does the WDT get reset after the processo

I am using a PIC16C74. I was wondering if the watchdog timer is automatically reset after the PIC comes out of sleep mode, where the awakaning was caused but a PORTB,0 rising edge interrupt? This could mean that the WDT would reset the chip, if the WDT was just ready to trip when coming out of sleep, and you didn't yet run the CLRWDT in your interrupt service routine code. I would appreciate any information. Thanks! ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

Hi Ry, I just ask this question a few days ago on this list and got no response. I also ask the tech support at Microchip and they said the watchdog is reset before stopping the clock, not after. I ask them if the sequence: bcf STATUS,GIE clrwdt sleep clrwdt bsf STATUS,GIE would insure no watchdog timer. I did not get a clear answer on that, and have ask for a clarification, but the implication is even that code may get a watchdog reset between the sleep and the clrwdt. If that is true then the internal watchdog cannot be used to wakeup from sleep if interrupts are also used in the system. Possible solutions are to assure another interrupt wakes up the processor before the watchdog timer, or write your startup code to separate the watchdog reset just after sleep from other watchdog timeouts. (Or just disable the damn thing.) Chip Ry Lato wrote: >I am using a PIC16C74. I was wondering if the watchdog timer is >automatically reset after the PIC comes out of sleep mode, where >the awakaning was caused but a PORTB,0 rising edge interrupt? >This could mean that the WDT would reset the chip, if the WDT was just >ready to trip when coming out of sleep, and you didn't yet run the >CLRWDT in your interrupt service routine code. I would appreciate any >information. Thanks!