bugAVR C Runtime Library - Bugs: bug #19178, Propose: Exact-Delay

 
 

bug #19178: Propose: Exact-Delay

Submitted by:  Michael Heidinger <overthere>
Submitted on:  Thu 01 Mar 2007 01:51:26 PM UTC  
 
Category: Feature RequestSeverity: 1 - Wish
Priority: 3 - LowItem Group: libc code
Status: FixedPercent Complete: 0%
Assigned to: Joerg Wunsch <joerg_wunsch>Open/Closed: Closed
Release: AnyFixed Release: None

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Wed 09 Jun 2010 08:16:28 AM UTC, comment #1:

Provided you are using a patched compiler (the patch is
supposed to be integrated into GCC some day), you can get
exactly this with the function

__builtin_avr_delay_cycles()

which has been documented by <avr/builtins.h> for some time
now. Exact delays for very short cycle counts must be
provided by the compiler rather than the library, as the
overhead to setup the delay has to be taken into account,
and this overhead is only known to the compiler.

Joerg Wunsch <joerg_wunsch>
Project AdministratorIn charge of this item.
Thu 01 Mar 2007 01:51:26 PM UTC, original submission:

Hi,

as I cannot add any proposes, I would like to propose a new macro for the lib in the support-area.

For some applications you need exact delays. delay.h already exists, but this workes with a timer and is not that exact if you need only a delay of 2-15 clocks.

I was trying to realize this with defines, but this makes the source not readable.

Whats about a function "exact_delay(20);" and the lib calculates the waiting? 20 means 20 clocks.

Please realize my propose.

Thanks

Michael Heidinger

Michael Heidinger <overthere>

 

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  • -unavailable- added by joerg_wunsch (Posted a comment)
  • -unavailable- added by arcanum (Updated the item)
  • -unavailable- added by overthere (Submitted the item)
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    Follow 8 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 09 Jun 2010 08:16:28 AM UTCjoerg_wunschStatusNone=>Fixed
      Assigned toNone=>joerg_wunsch
      Open/ClosedOpen=>Closed
      ReleaseNone=>Any
    Mon 17 Mar 2008 04:31:19 PM UTCarcanumCategoryLibrary=>Feature Request
      Severity3 - Normal=>1 - Wish
      Priority5 - Normal=>3 - Low
    Thu 01 Mar 2007 01:51:26 PM UTCoverthereCarbon-Copy-=>Added overthere

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