Drasko DRASKOVIC
2013-05-17 14:29:01 UTC
Hi all,
I have two Pandaboards that I want to clock-synchronize.
I was thinking about this test scenario :
* Connect GPIO pin from each Padaboard to oscilloscope channel
* Toggle GPIO each second
* Compare signal offsets on oscilloscope
At this moment I have fear that GPIO interrupt might introduce to much
jitter. Is this a relevant jitter or not ?
Would it help if GPIO toggling be moved to kernel
(https://github.com/mirko/gpio-toggling---linux-kernel-module) ?
Second, I was looking at the PPS API. I can see here parallel port
generator : http://lxr.linux.no/linux+v3.9.2/drivers/pps/generators/,
but it seems that GPIO pin PPS generator does not exist. I am not sure
why, but the reason might be a jitter I mentioned (this is my fear).
What is the usual strategy that synchronicity is measured in this case
and can you point me to some open source tools that can help me do
this task.
Best regards,
Drasko
I have two Pandaboards that I want to clock-synchronize.
I was thinking about this test scenario :
* Connect GPIO pin from each Padaboard to oscilloscope channel
* Toggle GPIO each second
* Compare signal offsets on oscilloscope
At this moment I have fear that GPIO interrupt might introduce to much
jitter. Is this a relevant jitter or not ?
Would it help if GPIO toggling be moved to kernel
(https://github.com/mirko/gpio-toggling---linux-kernel-module) ?
Second, I was looking at the PPS API. I can see here parallel port
generator : http://lxr.linux.no/linux+v3.9.2/drivers/pps/generators/,
but it seems that GPIO pin PPS generator does not exist. I am not sure
why, but the reason might be a jitter I mentioned (this is my fear).
What is the usual strategy that synchronicity is measured in this case
and can you point me to some open source tools that can help me do
this task.
Best regards,
Drasko