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*** Warning: possible obsolete documentation!!                              ***
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In order how to compile and install the package, please, refere to the site
<https://ntp.isc.org/bin/view/Dev/LinuxImplementationLinuxPPS> or see its
snapshot into local file "httpdocs.txt" (the file may be outdated, so if you
can use the URL as updated documentation).


Enjoy,

Rodolfo <giometti@linux.it>


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INTRODUCTION
============

Here a reference clock support for NTP package who can read time data
from a Trimble Acutime 2000 GPS antenna (or by a generic GPS device
connected to the serial line who supports TSIP protocol).

This reference clock is just a fixup of the existing file
"refclock_ripencc.c" distribuited with NTP package version
"4.2.0a+stable". I just fixed the big/little endian support and the
PPS support in such a way you may use this reference clock even
whitout PPS support in your kernel.

I test this reference clock with and without PPS support by using it
on a MPC8xx board (ppc) runnig linux 2.4.24. Tests with PPS support
has been made by using code at:

   ftp://ftp.enneenne.com/pub/projects/linuxpps

In this distribution you can find both the patch against NTP version
"4.2.0a+stable" and the new file "refclock_ripencc.c" already patched.


INSTALLATION
============

If you obtain "ntp-4.2.0a+stable" package you should apply the
following patches:

   patch.ntp-4.2.0a+stable-configure.in
   patch.ntp-4.2.0a+stable-refclock_ripencc.c
   patch.cross_compiling			(only for cross compiling)
   
Here my installation/compilation steps:

giometti@zaigor:~/Projects$ tar xfz ntp_4.2.0a+stable.tgz 
giometti@zaigor:~/Projects$ cd ntp-4.2.0a+stable/
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ patch -p1 < ../patch.cross_compiling 
patching file configure.in
Hunk #1 succeeded at 26 (offset 1 line).
patching file ntpdc/Makefile.am
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ patch -p1 < ../patch.ntp-4.2.0a+stable-configure.in 
patching file configure.in
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ aclocal && autoconf && automake
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ patch -p1 < ../patch.ntp-4.2.0a+stable-refclock_ripencc.c 
patching file ntpd/refclock_ripencc.c
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ ./configure --host=ppc-8xx-linux --without-crypto --enable-RIPENCC --disable-ATOM --disable-JUPITER --disable-NMEA
[...]
giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ make
[...]

In order to allow "configure" to detect PPS support correctly you must
properly install it (use the above package or a compatible one) and be
sure to have copied the file "timepps.h" (provided by the PPS support
itself) into your include directory path in the "sys" subdirectory (on
my toolchain I put it under
"/usr/local/ppc-8xx/ppc-8xx-linux/include/sys/").

To verify that configure has really found your PPS support you can use
the following command just after it has finished his work:

   giometti@zaigor:~/Projects/ntp-4.2.0a+stable$ grep HAVE_PPSAPI config.h
   #define HAVE_PPSAPI 1


NOTE
====

For further info on this reference clock support, please, refere to
the file "driver43.html" into NTP source tree.