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CJack5
Novice
1,525 Views

NTP reading GPIO PPS

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I have a Trimble Thunderbolt GPS that generates a super-accurate PPS signal that I'd like to connect to a Galileo GPIO port and then to NTP for a Stratum 1 NTP server. Has anyone done this or have any suggestions. I did see some posts about getting PPS working in the kernel; but then nothing about the final step of interfacing that to NTP.

Thanks in advance!

Clay Jackson

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Pedro_M_Intel
Employee
170 Views

Hello N7NM,

I personally haven't tried this but I found . There, the user AlexT provides a way to get NTP into your image, I suggest you to check it out.

I see you already checked , I believe that thread is very helpful in regards to pps. So, you could combine the information in both threads in order to continue with your project. I hope this helps.

Let us know,

Peter.

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3 Replies
Pedro_M_Intel
Employee
171 Views

Hello N7NM,

I personally haven't tried this but I found . There, the user AlexT provides a way to get NTP into your image, I suggest you to check it out.

I see you already checked , I believe that thread is very helpful in regards to pps. So, you could combine the information in both threads in order to continue with your project. I hope this helps.

Let us know,

Peter.

View solution in original post

CJack5
Novice
170 Views

Peter - very good! I think I'm about 95% of the way there. Two more questions, if I may - the NTP PPS drivers normally access the PPS by an entry in /dev - I assume in this case that would be the same path that you used for the asserts in the pps-gpio thread. Also, can you tell me if the GPIO inputs will tolerate TTL levels (5V) or are they 3.3V only.

Will keep you posted on my progress!

Thanks!

Pedro_M_Intel
Employee
170 Views

I believe you are correct. The way to access the PPS is probably in /sys/class/pps/pps0/assert.

As you can see in http://www.intel.com/content/www/us/en/support/boards-and-kits/intel-galileo-boards/000005735.html Galileo Datasheet under Arduino Shield Supported Features, Galileo's IO supports 3.3v or 5v. This can be set with the IOREF jumper:

 

 

 

Peter.

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