Re: High res timer

On Sep 6, 3:46 pm, "Jon Slaughter" <Jon_Slaugh...@xxxxxxxxxxx> wrote:
To be honest, I guess I really need a high res timer becaues I also want to
send data. The data doesn't have to be syncronized though as the pc will be
a "master". Although I will need to send the data to the port in a timely
fashion at some configurable rate from 1khz to 100khz(the faster the
better). (jitter is not a huge concern though)

I figure that if I time a thread that, say, runs at 150mhz, I can setup a
delay to lock in on a specific rate. But in this case I'm wasting a lot of
cycles delaying the thread. If I had a Thread.Sleep that was more accurate
than 1ms then it would be a piece of cake. (I understand that theres a lot
of task switching invovled and stuff but I'm not looking for the optimal
method but something that works and doesn't bring the system to a screaching
halt).


First off, the windows timer has a resolution of something like 15-45
ms (depending on the OS). Sleep(1) can last 15 ms. That's just the
way it is.

You could potentially use QueryPerformanceCounter in some sort of spin
loop to get the resolution you want (i.e. call it multiple times and
break out of the loop when you find that you've gone beyond the time
span). Problem is you have to give up timeslices back to the OS to
keep your spin loop from grabbing all the cycles. Issue is the same
as above, sleep(0) can give up more than just the time slice to the
OS. I think there is also a Multimedia counter somewhere but IIRC,
the resolution is only 1 ms

You really should consider allowing the port to signal you when you
receive data rather than polling the port to see if there is data.

.