[Pool] GPS now announcing the Leap Second

Philip Gladstone philip at gladstonefamily.net
Thu Jan 22 22:21:37 UTC 2015

On 1/22/15 15:49, Hal Murray wrote:
>> I think that some more testing is required of my servers.....
> What software are you using and what type of GPS device?
The GPS device(s) are an SSR-6T (contains a µblox LEA-6T) and a VK16U6 
(generic module containing some sort of NEO-6). Each is attached to its 
own server.

The firmware runs on an STM32F407 (32-bit ARM) board and is cobbled 
together from various bits of existing open source -- and custom code to 
handle the GPS chip, time synchronization and NTP server). The IP stack, 
RTOS and PTP code are all open source from other projects.

The reason to build this was to experiment with PTP. I have a blog where 
I describe the issues and the bringup process: http://n1dq.blogspot.com/ 
(ignore the stuff about printers!)

My goal is to opensource the code (and provide build instructions) and 
build instructions to duplicate the work. It cost me under $75 per board 
(with the generic GPS), and most of the cost was in the STM32 board. I 
don't have any ideas around cases -- one of the systems just sits on a 
window sill (so it can see the sky).

Would anybody else be interested in building one of these? It might 
encourage me to get the writeup into some semblance of order.


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