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Attention: RC-CAM.com will be closing down August 2021.

The RC-Cam.com forum was the very first online community dedicated to the advancement of wireless video cameras on radio controlled (R/C) models. This is now called "FPV" (First Person View). We are proud of the contributions that our members have made to the FPV hobby.

We've seen significant changes over the last twenty years. Initially there were a lot of eager R/C hobbyist that built their own video systems. Allowing these creative individuals to share their work was the purpose of this site. Now the FPV market is flooded with low cost systems; Sadly DiY FPV video projects are now rarely discussed.

RC-CAM.com (main site and forum) will be closing down August 2021. This was announced several months ago (March 2021) to allow our members ample time to download any information that is important to them. After the site is shutdown the information will no longer be available here.

We appreciate every member's involvement with advancing the FPV hobby. It is indeed sad to say goodbye to all our online friends. Be safe and stay healthy.



How To Restore a PIC's OSCAL Value


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A common flash PIC microcontroller mistake involves the factory programmed Oscillator calibration (OSCAL) constant. This is a byte of data in the PIC that provides a correction value to it's internal clock frequency. For example, decoding or generating an accurate R/C pulse requires that the OSCAL have an accurate value. If your PIC project uses an external oscillator then you can totally ignore OSCAL. But if you use the internal oscillator, then treat the OSCAL feature with respect. Don't erase or write to it!

The issue is that many of the hobby based programming systems make it too easy to erase this value. Hence, the PIC's oscillator is no longer accurate enough for common R/C project applications. If you have recorded the value before using the chip then you can easily re-write it back. But, you know what they say about hindsight.

Fortunately, PIC's are cheap and you can just toss the ones with messed up OSCALs. However, if you would like to restore the value, there is a solution using EDN Magazine's design idea by Noureddine Benabadji: Click Here.

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  • 3 weeks later...

Hi, Mr Cam

A PicBasicPro version of this utility ( for 12F6xx devices ) is also downloadable here :

see : .melabs.com/resources/samples/12F675/PBP/RECOVER.BAS

in the Labs X4 sample programs

http://www.melabs.com/resources/samples.htm

Alain

Edited by Acetronics
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