Hi Dave,

At 6:49 AM 9/16/98, Dave Johnson wrote:
>I've just set up a PIC development system and am embarking on a long and
>(I hope) fruitful project involving PICs controlling other hardware. For
>the moment I'm using 16F84s, the 10 MHz variety. (Despite the plethora of
>16C84 documentation, it appears they don't actually exist anymore, is
>that correct?) I've been lurking here for a week or so, saving off
>appropriate posts for later perusal, but now have a quick question:

        Jameco has a 4MHz 'c84 in their latest catalogue, for $1 more than
the equivalent 'F84 part, same price as the 10MHz 'F84 part. And using the
flash part means no UV erasing, a big advantage. I would guess that any
program that runs on the 'c84 can run on the 'F84 without modification.
µChip has highlighted the differences between the 'c84, ans 'F84 devices in
Appendix E in their data book on the 'c84.

>
>Is the configuration word the same format and location (0x2007) on both
>chips? I'm assuming so since I haven't found anything to tell me
>otherwise
>
>I'm using MacPIC for assembly/chip programming (highly recommended, by
>the way, for Mac users) with a PICStart+, and with 16F84 selected in
>MacPIC, the configuration word never verifies after write. I'm guessing
>this is a MacPIC bug: If I select 16C84 it verifies fine, so I've been
>doing that when I need to write the config word, and it seems to work. I
>just want to make sure I'm not inadvertently doing something nasty :-)

        Yes, the configuration word is at the same location.

        I'm also using MacPic (and agree it's great) with a Warp-3
programmer, and was running into the same problem. This had not become
obvious until I started programming a 'c71 chip where the configuration
word had to be programmed each time it's erased.

        As to the format, I just noticed, one of the differences mentioned,
was that the polarity of the Power-up timer enable bit (PWRTE) is reversed.
Could this be the reason the configuration word isn't verifying ?
        Kevin are you listening?
        Although the PWRTE bit for the 'c84 has the same sense as the 'c71?

        I don't think anything nasty will happen since the state of the
power-up timer is likely not critical, for you at this point.
>
>Dave Johnson