NTP-Server with Raspberry Pi and Sure Electronics GPS Eval board

Inhaltsverzeichnis

1 Scope
2 References
3 Implementation
- 3.1 OS choice and preparation
4 Images

1 Scope

It was already a few years ago when I bought a Sure Electronics GPS timing receiver. Though, there was never enough time to complete and deploy it. I have done it now.

The Sure receiver is nice because it has 3,3V IO pins, and this matches perfectly with a Raspberry Pi. So it's a good point using it.

Obviously many people have problems with the NTPD that comes with the recent raspian distributions: ntp 4.2.6p5. It does not support PPS...

It is rather easy to make the kernel PPS aware, but ntp still is not capable of using it. I needed to recompile the ntp package so that I was able to use it. The symptom therefore is:

The tool ppstest does report the reception of a pulse, but even if you configure NTP correctly, it won't give you an output with PPS using the command ntpq -p.

2 References

3 Implementation

3.1 OS choice and preparation

First of all I decided to use a minibian image:

https://sourceforge.net/projects/minibian/files/2016-03-12-jessie-minibian.tar.gz

because I don't want to create a really big thing. I just want to have an NTP server.

Unpack, write it to the SD card, as described so often everywhere on almost every RPI page.
Use gparted to resize the root partition to the rest of your SD card. We should not waste space.
Log in using uid root pwd raspberry (default). Note that opposed to Raspian, there is no user "pi".
apt-get update; apt-get upgrade and update the minibian image.
Give it a nice hostname, editing the file /etc/hostname and reboot.
Edit /boot/config.txt - Add dtoverlay=pps-gpio,gpiopin=18 on a new line. - Connect the PPS signal of the Sure board to this pin. Don't get the pin wrong :-)