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[avr-libc-dev] [patch #6236] Improving _delay_us and _delay_ms
From: |
Florin-Viorel Petrov |
Subject: |
[avr-libc-dev] [patch #6236] Improving _delay_us and _delay_ms |
Date: |
Wed, 17 Oct 2007 16:13:26 +0000 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7 |
URL:
<http://savannah.nongnu.org/patch/?6236>
Summary: Improving _delay_us and _delay_ms
Project: AVR C Runtime Library
Submitted by: fonitzu
Submitted on: Wednesday 10/17/2007 at 16:13
Category: None
Priority: 5 - Normal
Status: None
Privacy: Public
Assigned to: None
Originator Email:
Open/Closed: Open
Discussion Lock: Any
_______________________________________________________
Details:
_delay_us and _delay_ms are improved with a fall-back functionality, that
means, instead of clipping to the maximal possible delay in case of exceeding
allowable argument value, they behave so:
_delay_us will call _delay_ms instead
_delay_ms will perform a delay up to 6.55 seconds using a 0.1ms delay loop
This will avoid subtle errors on the user side when one require delays longer
than allowed - for example _delay_us(1000) will be compiled as _delay_ms(1)
instead.
As proved on my computer, the compiler, using optimizations, will simply
replace _delay_us with _delay_ms if it's the case and _delay_ms will be
expanded to a small loop only if it's necessary.
Known problems:
- the user will not be informed in a fall-back case
- for _delay_ms it will be always a trade-of between loop resolution (0.1ms
now) and induced error (loop counter overhead)
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Wednesday 10/17/2007 at 16:13 Name: delay.h Size: 6kB By: fonitzu
<http://savannah.nongnu.org/patch/download.php?file_id=14157>
_______________________________________________________
Reply to this item at:
<http://savannah.nongnu.org/patch/?6236>
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- [avr-libc-dev] [patch #6236] Improving _delay_us and _delay_ms,
Florin-Viorel Petrov <=