Microchip PIC Forum: Re: [piclist] Re: 12F675 Startup Problems

Friday, December 7, 2007

Re: [piclist] Re: 12F675 Startup Problems

I have run serial comms at 9600 baud and lower using Microchip internal
RC oscillators quite successfully for years. The secret is to keep your
dialog length very short, one or two bytes at a time so that clock drift
won't affect your data much.

DLC

Eirik Karlsen wrote:
> Well...as I've said before serial coms should always be done with x-tal
> or maybe resonator osc.
> Trying to get a RC osc to run within 5 - 10% in accuracy and stability
> just isn't possible
> in practice...you might get it to work but when temperature changes, or
> a wire gets too
> close to chip or tracks, or whatever that can pull the osc happends
> you'll get tagged.
>
>
>
> kg4pid wrote:
>
>> To make it work I had to change the the value that gets moved into
>> OSCCAL. Since the serial routine that I used had been around awhile
>> I can only assume that the problem is in the Pic oscilator. Don't
>> know what to do to fix it though as I don't want to have to
>> calibrate each pic chip.
>>
>> Max
>>
> --
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> Regards
> Eirik Karlsen
>

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