Recal clock - Electronic Circuits Projects Diagrams Free

homemade24 · 20th January 2009, 07:33 PM

I just added
bsf STATUS, RP0 ;Bank 1
call 3FFh ;Get the cal value
movwf OSCCAL ;Calibrate
bcf STATUS, RP0 ;Bank 0
had to to get the code working right
If I'm thinking right (that's scary) depending were you put this in the code
the clock could only be recal @ programming or could be recal everytime the chip is powered up. if so which is the standard way of doing it. and is it a problem if you recal every time the chip is powered up
thanks

mvs sarma · 20th January 2009, 09:37 PM

Quote:

Originally Posted by homemade24

I just added
bsf STATUS, RP0 ;Bank 1
call 3FFh ;Get the cal value
movwf OSCCAL ;Calibrate
bcf STATUS, RP0 ;Bank 0
had to to get the code working right
If I'm thinking right (that's scary) depending were you put this in the code
the clock could only be recal @ programming or could be recal everytime the chip is powered up. if so which is the standard way of doing it. and is it a problem if you recal every time the chip is powered up
thanks

Please see this link
12F675 tutorial 3 : Adding a PIC Serial port.

homemade24 · 21st January 2009, 02:42 AM

thanks
is that a YES or NO or did it mess something

**Nigel Goodwin** · 21st January 2009, 09:45 AM

It's absolutely critical that you don't erase the calibration value at 0x3FF - any decent programmer shouldn't allow you to do this, it should read and restore the value automatically.

The code for setting the calibration value is normally placed right at the beginning of the program to ensure it's set whenever the PIC boots up.

Bear in mind this isn't 'calibrating' the chip, it's simply using the value from when it was calibrated back in the factory.

homemade24 · 21st January 2009, 04:53 PM

thanks Nigel
that clears it up and I guess calibrate was was not the correct term
it's more go get the factory setting and it need to do that with every boot up

**Nigel Goodwin** · 21st January 2009, 05:19 PM

Quote:

Originally Posted by homemade24

thanks Nigel
that clears it up and I guess calibrate was was not the correct term
it's more go get the factory setting and it need to do that with every boot up

Yes, every time.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar
Title	Starter	Forum	Replies	Latest
what clock does it run at	desijays	Micro Controllers	9	19th April 2008 09:05 AM
Binary Clock help (sorry for numerous Clock threads)	Krumlink	Electronic Projects Design/Ideas/Reviews	12	12th September 2007 11:44 PM
LED clock - would appreciate any help	lieutenant L	Electronic Projects Design/Ideas/Reviews	6	10th February 2006 03:41 PM
Help me on basketball's game clock and shot clock!	syaw_007	Electronic Projects Design/Ideas/Reviews	1	6th September 2004 10:50 PM
help with a clock!!	ciao_king	General Electronics Chat	10	1st August 2004 10:11 AM

20th January 2009, 07:33 PM	#1
homemade24	Recal clock I just added bsf STATUS, RP0 ;Bank 1 call 3FFh ;Get the cal value movwf OSCCAL ;Calibrate bcf STATUS, RP0 ;Bank 0 had to to get the code working right If I'm thinking right (that's scary) depending were you put this in the code the clock could only be recal @ programming or could be recal everytime the chip is powered up. if so which is the standard way of doing it. and is it a problem if you recal every time the chip is powered up thanks

21st January 2009, 02:42 AM	#3
homemade24	thanks is that a YES or NO or did it mess something

21st January 2009, 09:45 AM	#4
Nigel Goodwin	It's absolutely critical that you don't erase the calibration value at 0x3FF - any decent programmer shouldn't allow you to do this, it should read and restore the value automatically. The code for setting the calibration value is normally placed right at the beginning of the program to ensure it's set whenever the PIC boots up. Bear in mind this isn't 'calibrating' the chip, it's simply using the value from when it was calibrated back in the factory. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

21st January 2009, 04:53 PM	#5
homemade24	thanks Nigel that clears it up and I guess calibrate was was not the correct term it's more go get the factory setting and it need to do that with every boot up