> >From the reply for Jinx I can see that the variation of watchdog
> timer (WDT) period is linear with temperature but he didn't say what
> % it changes between hot and cold.

You can pick an intermediate temperature and calculate from there

> Anybody got a temperature
> coefficient? I'm talking about the PIC16F628's but I presume it's
> similar technology for all of them.

IMHO the table IS defining the temp co-eff for WDT

> Also does anyone know how variable WDT period is between IC's?
> The Microchip data sheet just gives min typical and max.

The book says 18ms is the "typical" value at 25C. Using the
maximum WDT pre-scaler of 128, this gives you 128 x 0.018
= 2.304s. The nearest I got to 2.304 is at 22C, but I only claim
to have tried "careful" measurements. If you really want to get
down and dirty you'll need to do laboratory-grade testing. This
also applies to differences between batches. There are no
guarantees that any PIC is a plug-in for another

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads