On Thu, 20 Oct 2016 06:15:39 +0000
Ilia Platone <i...@iliaplatone.com> wrote:
> I need some clues on the Linux PPS subsystem.
> I am trying to take some timestamps of events on a GPIO using an ARM
> SBC, and noticed that the kernel linux can be interfaced to a PPS
> signal, wanted to sync another GPIO to a GPS receiver for time
> reference. I need to know how much precise this system can be. How much
> resolution can I obtain with a cheap receiver (maximum quantization
> frequency)?
Using GPIO for precision timing is the wrong approach. If you are
already using an ARM processor, it is much better to use the time/capture
unit to time events. These are counters which run usually with 50-200MHz
giving you a resolution of 5ns to 20ns. Their advantage is that you are
not limited by the interrupt latency and (mis)behaviour of the software,
but handle everything in hardware.
Attila Kinali
--
Malek's Law:
Any simple idea will be worded in the most complicated way.
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