2008-12-01 12:33:09 gptimer questions...
John Doe (UNITED STATES)
Message: 66098
what is the finest resolution that i can get with /dev/timer[0-7] ?
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2008-12-01 13:32:53 Re: gptimer questions...
Robin Getz (UNITED STATES)
Message: 66101
Dustin:
You can get 1/SCLK.
-Robin
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2008-12-01 13:43:01 Re: gptimer questions...
John Doe (UNITED STATES)
Message: 66103
how can i find out what my sysclock is exactly or to set it myself?
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2008-12-01 14:02:48 Re: gptimer questions...
Mike Frysinger (UNITED STATES)
Message: 66107
you should know this already considering you must define it for your u-boot port
if you're using a development board, then just look at the u-boot output or /proc/cpuinfo under Linux
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2008-12-01 14:44:20 Re: gptimer questions...
John Doe (UNITED STATES)
Message: 66109
now i have a few questions:
does the timer automatically roll over to zero?
if it does is there some way from userspace that i can check this?
if it is 1/sclk then should i be getting more than ~1910 on the isr count every second?
I am trying to get to nano seconds using the timers under /dev. The file the I have been using to work from is the bfin_simple_timer.c. The resolution doesnt seem to finite enough for our project. is there anything that i can do to make the resolution in that file in nano seconds? Also, is there a way that i can clear or reset the timer?
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2008-12-01 17:00:51 Re: gptimer questions...
Mike Frysinger (UNITED STATES)
Message: 66111
the HRM already describes the full behavior of the gptimer
the manual explains that the finesnt you can do with any peripheral is 1/SCLK
the driver source for bfin_simple_timer.c is pretty simple ... read the ioctl() function to see what it can do
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2008-12-02 01:41:26 Re: gptimer questions...
Wolfgang Muees (GERMANY)
Message: 66120
It's a bit questionable to want to get the current time with a precision of 1 ns, if the code which retrieves this information has a much longer inaccuracy. You will never know how fast the code is executed due to cache and interupt behaviour.