WDT and temperature

[ilias80]

Hello,
I am working on battery operated product and so the sleep use is necessary. However timing is somewhat critical and I am relying on the watchdog time-out time and using a counter to obtain a countdown function (say alarm in X mins). I know that the WDT is dependent on temperature (and isn't even the same over the same temperature for each chip of the same model)and I am using a temp sensor in my circuit. My question is: Before going to sleep, how can I check what the time-out time is (say using a timer1 counter) ? That way I can scale my counter appropriately to get the right countdown time.
BTW, I am using a PIC16F688 running with the internal clock and I can't use any additional hardware because I don't have any space left on the PCB.

Thank you!
Ilias

[PCM programmer]

See the Microchip appnote AN828 for some ideas:

Measuring Temperature with the PIC16F84A Watchdog Timer
http://ww1.microchip.com/downloads/en/AppNotes/00828a.pdf

[Guest]

My concern is if it can be done with timer1 using the HF internal oscillator? (the PIC itself is running on the HF oscillator)