Timer resolution et al

Stevens Brian BPSTEVENS at qinetiq.com
Tue Mar 9 08:11:29 UTC 2004


I have been following the thread on timer resolution etc as I have a need
for the following:

	A timer with an accuracy of sub milliseconds
	A timer that is not dependant on the underlying clock tick.

I am working with the pc386 port and have formulated some ideas:
	Use one of the other counters on the timer chip.
		This seems a straight forward way to do the job without
altering the existing code, and since most timer chips have more than 1
counter it could probably be extended to other ports. However, it seems that
the other timer outputs are not normally conected to the interrupt
controller. 

	Use the real time clock
		In the PC the real time clock chip can provide a periodic
interrupt with a resolution of ~122 micro seconds and this line is connected
to the interrupt controller.

I would prefer to go with the 1st method as I think that this would have
more generall application. If any one can help me with the hardware parts
then I am willing to have a go at the code for the pc386. (this is a home
job not a work job so it may take some time)

Thank You

Brian Stevens

QinetiQ
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Ively Road,
Farnborough,
Hampshire
GU14 0LX . 
UK

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