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

Friday, December 7, 2007

Re: [piclist] Re: 12F675 Startup Problems

Each PIC comes with a different osccal value so you shouldn't have to put a value of your own in there.

Otherwise use an external resonator.

-------Original Message-------

From: kg4pid

Date: 12/07/07 23:33:55

To: piclist@yahoogroups.com

Subject: [piclist] Re: 12F675 Startup Problems

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

--- In piclist@yahoogroups.com, "kg4pid" <kg4pid@...> wrote:
>
> I'm using a serial routine on a 12F675 and started by sending out
the
> word "HELLO" over and over. Funny thing is while it's powered on I
get
> nothing out, but the instant I remove power it sends out 10 or 11
> characters. The filter cap is powering it for that fraction of a
> second. The circuit is being powered by a 9V battery with a 78L05
to
> regulate it at 5V. My meter reads 4.99v at the pic chip. A logic
probe
> connected to the output blinks the whole time it is powered up
which
> should mean that its sending something. I had to include this bit
of
> code at the very beginning before I got anything at all.
> call 0x3FF ; Retrieve Factory Calibration
> BANKSEL OSCCAL ; BANK1
> movwf OSCCAL
>
> Anyone have any ideas as to what might cause a problem like this?
>
> Thanks, Max
>