* Wallclock - calendar option
@ 2012-02-14 11:13 qber_
2012-02-14 14:45 ` Bernard Fouché
0 siblings, 1 reply; 2+ messages in thread
From: qber_ @ 2012-02-14 11:13 UTC (permalink / raw)
To: ecos-devel
Hello all.
I want to discuss an option of Wallclock device framework.. Now the wallclock supports two option : init_get and set_get. This functions support time counted from 1970-01-01 00:00:00. The idea is to add the support for calendar insted of seconds counter. Most of applications uses calendar not seconds counter.
The change for handling date and time for me is a result of working with STM32F2x processor which has calendar based RTC. The is no sense for converting calendar to seconds and then back again to calendar.
The problem is which date and time format should be selected (if this change will be added to officail reposotory).
Best Regards
Qber
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Wallclock - calendar option
2012-02-14 11:13 Wallclock - calendar option qber_
@ 2012-02-14 14:45 ` Bernard Fouché
0 siblings, 0 replies; 2+ messages in thread
From: Bernard Fouché @ 2012-02-14 14:45 UTC (permalink / raw)
To: ecos-devel
Le 14/02/2012 12:09, qber_ a écrit :
> Hello all.
> I want to discuss an option of Wallclock device framework.. Now the wallclock supports two option : init_get and set_get. This functions support time counted from 1970-01-01 00:00:00. The idea is to add the support for calendar insted of seconds counter. Most of applications uses calendar not seconds counter.
> The change for handling date and time for me is a result of working with STM32F2x processor which has calendar based RTC. The is no sense for converting calendar to seconds and then back again to calendar.
> The problem is which date and time format should be selected (if this change will be added to officail reposotory).
> Best Regards
> Qber
Hello Qber,
time_t (or any similar integer counter) is used everywhere inside CPUs,
calendar time is used only to interface with entities externals to the
MCU/CPU like humans, files/databases, network. Usually there is much
more internal time calculations than time data output from a CPU in
calendar representation. It's very hard to see any gain by using
nightmarish calendar calculations when simple integer arithmetic can be
used instead. Write a function that adds a variable amount of time to
data represented as calendar date/time and compare it to an integer
addition. Conversion functions between time_t and calendar date/time
exist from 1970-01-01 00:00:00. Even Windows uses an integer
representation, even probably the Maya as shown by their overflow
problem at the end of the year.
Bernard
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2012-02-14 11:13 Wallclock - calendar option qber_
2012-02-14 14:45 ` Bernard Fouché
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