ravinder are
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64 bit conter and the Timer call outs
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ravinder are
11/07/2011 7:16 PM
post89927
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64 bit conter and the Timer call outs
Dear OSTech,
I am porting the QNX to a platform which has 64 bit counter Timer. I have few Questions on Timer callouts.
1. Timer_load callout
We have to set the MATCH value in the Match register or comparator register , it will be writing in my own registers ,
there is no problem whether timer value is 32 bit/64 bit.
2. Timer_value callout
It has to return a counter incremented value to the caller from the last Timer interrupt to till now. If the Timer
counter resets on every Timer interrupt the callout is fine to return the value as
Latest counter value (i.e. return_value = current counter value - 0 , 0 bacause the counter reset on last
interrupt).
If the Timer counter is a continuous incrementing and not resetting on Timer Interrupt , how to return the delta value
to the caller from last interrupt to till now.
How does the 64 bit continuous incrementing timer will impact the QNX kernel. Does QNX has 64 bit timer support
currently ( ARM Generic Timer as an optional extension to an ARMv7-A or
ARMv7-R processor implementation.)
Thanks,
Ravinder
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