At 08:06 PM 11/6/02 +1100, Sean Alcorn - Avion SYD wrote:
>However just
>as I hit the program button, I realised I may have done one thing
>wrong. I did not open the Program/Verify window of MPLAB. If I had, I
>would have noticed that "Calibration Memory" was checked.
>
>I know this is bad news for a JW Part - unless you record the factory
>setting. Does this apply to EEPROM parts also?

MPLAB will NOT alter the value of the calibration registers if they contain
valid data.  The following is a copy/paste of the replies I received from
David Otten of Microchip.  He is apparently the person responsible for
writing the 12f675-specific portions of MPLAB.

Copy begins:

To: Dwayne Reid <dwayner@planet.eon.net>
Subject: Re: Calibration Memory for 12f675
Date: Wed, 11 Sep 2002 15:43:31 -0700
X-MIMETrack: Serialize by Router on USMail1/US/Microchip(Release 5.0.10
|March 22, 2002) at
09/11/2002 03:43:32 PM,
Serialize complete at 09/11/2002 03:43:32 PM

Hi Dwayne -

Thanks for the feedback. The programmers and ICD won't support changes to
the oscillator and bandgap calibration bits. They're always restored to
their factory settings after programming. Since the older EPROM devices
needed to be UV erased, the calibration windows were required which isn't
the case for the flash parts.

Best regards,

David Otten


To: Dwayne Reid <dwayner@planet.eon.net>
Subject: Re: Calibration Memory for 12f675
From: David.Otten@microchip.com
Date: Wed, 11 Sep 2002 18:03:12 -0700
X-MIMETrack: Serialize by Router on USMail1/US/Microchip(Release 5.0.10
|March 22, 2002) at
09/11/2002 06:03:13 PM,
Serialize complete at 09/11/2002 06:03:13 PM

Dwayne -

The calibration bits will be erased when the part is bulk erased per the
data sheet. Our programmers read the calibration bits then reprogram them
during the erase/program cycle. Our programmers won't lose the calibration
information.

Take care,

David


From: David.Otten@microchip.com
Date: Thu, 12 Sep 2002 10:50:24 -0700
X-MIMETrack: Serialize by Router on USMail1/US/Microchip(Release 5.0.10
|March 22, 2002) at
09/12/2002 10:50:26 AM,
Serialize complete at 09/12/2002 10:50:26 AM

Dwayne -

Our programmers won't (aren't suppose to) lose calibration data even if you
bulk erase the device and remove it. After the bulk erase, the calibration
bits are reprogrammed. As far as using the calibration window for other
parts, I'm not in the loop for tool specifics. I know everything is moving
to MPLAB 6.xx so hopefully that will be easier to use.

Take care.

David

<end of copy>


Hope this helps!

dwayne

--
Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax

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