delay_ms vs. osc speed.

E_Blue · Joined: 13 Apr 2011 Posts: 417

I have a program that uses three different oscillator configurations, I declared 48MHz at top of the program which is the usual speed but when is in low power mode I need to perform delays and the compiler make the calculation for 48MHz.
So, There's any way to indicate to the compiler that the main OSC is in a lower speed and the delay must use less cycles?
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Electric Blue

asmboy · Joined: 20 Nov 2007 Posts: 2128 Location: albany ny

post your code. TIMERS are your friend.
use a TIMER driven by Fosc for delays and then set a flag variable to indicate what Fosc value is active.
Then make your timer delays adjustable.

I could code this pretty quickly - but you have not
shown your pic or program structure..

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You asked this same question back in 2012. This post and the links in it
provide some answers.
http://www.ccsinfo.com/forum/viewtopic.php?t=47729
I suppose you're asking if there are any new features to the compiler
that allow this to be done more easily.

E_Blue · Joined: 13 Apr 2011 Posts: 417

@asmboy
Thanks, I think I will keep using TMR1 which is connected to a 32.768Khz crystal.

@PCM programmer
Yes, I'm trying to improve the code and making some changes.
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Electric Blue

Ttelmah · Joined: 11 Mar 2010 Posts: 19369

I think the route outlined in the code PCM_programmer pointed to, of using a stored 'multiplier factor' with the settings being done for the lower clock rate is by far the easiest and tidiest. A macro, or function can then be used for all timer calls.