PicForum

I have some code for the PIC17C42A, but I can't get them right now or for the foreseeable future.

I have managed to get some PIC17C44 parts.

I thought that code for PIC17C42A should run unchanged on the PIC17C44.

I re-compiled the code for PIC17C44 changing:

Code: Select all

   list   p=17c42a
   include   <P17c42a.inc>

to

Code: Select all

   list   p=17c44
   include   <P17c44.inc>

and the output hex file was identical.

However when I programmed a 17C44 it didn't work It's possible of course that the chip was bad, but I'm loath to burn more of these OTP parts as I only have a limited stock.

I've spent a long time looking at the datasheet and don't understand why it didn't, because unless I missed something the pin-out is identical. Are there some crucial parts of the memory map (e.g. interrupt vectors) that are different?

Can someone who knows these parts better than I give me some guidance.

It was a simple error - I needed to set the config bits!!! Now works fine!

Well done to track it down yourself.
Plainly this is related to the discussion at https://www.microchip.com/forums/m1192298.aspx

Yes, absolutely correct

David