Re: Displaying time
Re: Displaying time
- Subject: Re: Displaying time
- From: Negm-Awad Amin <email@hidden>
- Date: Fri, 22 Aug 2008 16:25:41 +0200
Am Fr,22.08.2008 um 16:15 schrieb Graham Cox:
On 23 Aug 2008, at 12:04 am, Negm-Awad Amin wrote:
This is what a analog PLL do, when it loads/unloads a ramp.
Analogue PLL design (Audio to GHz RF) were my bread-and-butter for
many years, so do be careful not to teach your granny to suck eggs
here ;-)
:-)
I developed digital PLLs in a former life.
If the system is busy, every timer-based solution will fail,
because the timer does not guarante nothing of none.
So you're stuffed in any case then, since the only other way is to
poll for a time change and there's no guarantee your main event loop
will be run in a timely fashion either.
Yup, as I said: If your system is busy, an application-based solution
is never very exact. But in the case, that the system is not busy (as
I said, his TS sounds like this), you get a more precise timer
(precise in relation to phase shifting, not related to frequency.
frequency is no problem here), if you reduce the number of events and
try to get close to the "tick tack".
I gueass, after running the software PLL 4, 5, 6 seconds (times), it
will burn less cpu performance.
Timers are in the event loop, so it's as broad as it's long... Since
the OP wants to display time to 1 second resolution *on screen*, you
are clearly not talking about wanting this to be very precise.
You'll be capped at 16mS anyway. A timer running at a few hertz is
simple, if not perfect nor scalable to a real-time OS.
Yes, this is, what I wanted to say: If you really, really need an
exact timer you should not use an application-bases solution on a OS
like OS X.
We can think about hundreds, but not about thousands.
Graham
Cheers,
Amin Negm-Awad
email@hidden
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