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PIC18F67J10 setup

 
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PrinceNai



Joined: 31 Oct 2016
Posts: 480
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PIC18F67J10 setup
PostPosted: Mon Dec 17, 2018 12:44 pm     Reply with quote
Dear Sirs,

I just got my hand on a bunch of PIC18F67J10. When I skimmed over the datasheet I noticed that this chip doesn't save the configuration the way other chips do. This is what it says:

Quote:

Unlike previous PIC18 microcontrollers, devices of the
PIC18F87J10 family do not use persistent memory
registers to store configuration information. The config-
uration bytes are implemented as volatile memory
which means that configuration data must be
programmed each time the device is powered up.


What does that mean from the compiler's point of view? Do I have to do something special in my code to get it running?

Best regards,
Samo
Ttelmah



Joined: 11 Mar 2010
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PostPosted: Mon Dec 17, 2018 1:02 pm     Reply with quote
No... Smile
The configuration values are stored in the top of the program memory, and
then automatically copied to the registers at boot.
Look at 5.1.2 in the data sheet.
PrinceNai



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PostPosted: Mon Dec 17, 2018 1:17 pm     Reply with quote
I wondered if I have a different datasheet. It is in 6.1.2.

Thanks a lot for the clarification.

Samo
Ttelmah



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PostPosted: Mon Dec 17, 2018 1:54 pm     Reply with quote
5.1.2, is in the 'memory organisation' section and has the comment:

Quote:

Because PIC18F87J10 family devices do not have persistent
configuration memory, the top four words of
on-chip program memory are reserved for configuration
information. On Reset, the configuration information is
copied into the Configuration registers.


Current release of the sheet straight from the MicroChip download site.

I just looked in my archive, and have a sheet that is ten years old, and it
still has this in the same place!. That has a lower letter though at the end.

However interesting. The sheet from the chip's direct page,has the section
numbers matching what you say.
However the section on the newer sheet still has the comment I quote
not the one you have!..

The key is that the chip hardware itself load this.
PrinceNai



Joined: 31 Oct 2016
Posts: 480
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PostPosted: Mon Dec 17, 2018 2:10 pm     Reply with quote
As you say, that is the only important thing. That no additional magic is needed :-).

P.S. The one I have is PIC18F87J10 FAMILY
DS39663F from https://www.microchip.com/wwwproducts/en/PIC18F67J10 downloaded yesterday.
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