=====PC Engines APU1 - Hopf NTP Server=====

====Requirements====
  * PC Enginges board, with DCD line (APU = ok, ALIX = not ok)
  * Debian 10 installed.
  * Getty on ttyS0 disabled.
  * APU1 to Hopf 7001 system connected over serial (see wiring below).
  * Hopf 7245 interface card configured for NTP (see 7245 interface board documentation).
  * [[http://www.ntp.org/downloads.html|NTP source code]] download.

====Documentation====
  * [[https://www.hopf.com/documents_en.php|Hopf documentation]]
  * {{ ::7001-7015dcf77_v0801_en.pdf |Hopf 7001DCF77 system}}
  * {{ ::7245_v0600_en.pdf |Hopf 7245 interface board}}
  * {{ :apu1.pdf |PC Engines APU1 board}}

  * Interface board 7245 DIP-switch settings.<code>
1 = on 
0 = off

SW1      SW2      SW3
12345678 12345678 12345678 
11111001 11000111 11111110
</code>

====Serial cable====
  * Construct a serial cable to route PPS to DCD.<code>

Hopf 7245     1 GND --------- 5 GND     PC Engines
S1 RS232      2 TXD --------- 2 RXD     APU1 board
              6 RTS (PPS) --- 1 DCD

</code>
====Install packages====
  * Install required tooling.<code>
apt install build-essential libcap-dev pps-tools
</code>

====Create device symlinks and PPS device====
  * Create new udev rules file.<code>
cat > /etc/udev/rules.d/hopf.rules <<EOF
KERNEL=="ttyS0", SYMLINK+="refclock-0"
KERNEL=="ttyS0", RUN+="stty -F /dev/%k 9600 cs8 -cstopb -parenb"
KERNEL=="ttyS0", TAG+="systemd", ENV{SYSTEMD_WANTS}="pps.service"
KERNEL=="pps0",  SYMLINK+="refclockpps-0"
EOF</code>
  * Reload the udev rules or reboot to test.<code>
ls -l /dev/refc*
lrwxrwxrwx 1 root root 5 Jan  4 14:37 /dev/refclock-0 -> ttyS0
lrwxrwxrwx 1 root root 4 Jan  4 14:37 /dev/refclockpps-0 -> pps0

ppstest /dev/pps0
trying PPS source "/dev/pps0"
found PPS source "/dev/pps0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1578145727.901770116, sequence: 1313 - clear  1578145072.692767609, sequence: 2
source 0 - assert 1578145728.000351551, sequence: 1314 - clear  1578145072.692767609, sequence: 2
source 0 - assert 1578145728.901731373, sequence: 1315 - clear  1578145072.692767609, sequence: 2
source 0 - assert 1578145729.000557999, sequence: 1316 - clear  1578145072.692767609, sequence: 2
^C

</code>

====Install NTP====
  * Disable and remove other time sync applications.<code>
apt-get remove --purge ntp chrony
timedatectl set-ntp false
systemctl stop systemd-timesyncd
systemctl disable systemd-timesyncd</code>

  * Add ntp user.<code>
groupadd ntp
useradd -c "Network Time Protocol" -d /var/lib/ntp -g ntp -s /bin/false ntp
usermod -a -G dialout ntp
  * Create directories.<code>
install -v -o ntp -g ntp -d /var/lib/ntp
install -v -o ntp -g ntp -d /var/log/ntpstats
</code>
  * Compile source code.<code>
tar zxf ntp-4.2.8p13.tar.gz 
cd ntp-4.2.8p13

# from Linux From Scratch
./configure CFLAGS="-O2 -g -fPIC" \
            --prefix=/usr         \
            --bindir=/usr/sbin    \
            --sysconfdir=/etc     \
            --enable-linuxcaps    \
            --enable-parse-clocks \
            --with-lineeditlibs=readline \
            --docdir=/usr/share/doc/ntp-4.2.8p13

make

make install
</code>
  * Add systemd services.<code>
cat > /etc/systemd/system/ntpd.service <<EOF
[Unit]
Description=Network Time Service
After=syslog.target ntpdate.service sntp.service
Conflicts=systemd-timesyncd.service

[Service]
Type=forking
ExecStart=/usr/local/bin/ntpd -g -u ntp:ntp
PrivateTmp=true

[Install]
WantedBy=multi-user.target
EOF

systemctl enable ntpd
systemctl start ntpd


cat > /etc/systemd/system/pps.server <<EOF
[Service]
Type=simple
ExecStart=/usr/bin/ppsldisc /dev/ttyS0
EOF
</code>  

====Hopf DCF /etc/ntp.conf====
  * Create /etc/ntpd.conf.<code>
#Stratum level when no ref source available
tos orphan 12

# Hopf DCF clock
# Mode 12 + 128 (pps) = 140
server 127.127.8.0     mode 140

fudge  127.127.8.0     refid PPS       # Reference identifier

#leapfile /etc/leap_second

restrict -4 default notrap nomodify nopeer noquery
restrict -6 default notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1

statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable

driftfile /var/lib/ntp/ntp.drift

</code>

====Check timecode====
<code>
ntpq -c 'cv 0 timecode'
timecode="\x02CB154556010120\x0a\x0d\x03"

</code>
====Nagios Hopf 7001 check====
<code>#!/bin/bash
#
# Tested with Hopf 7001 DCF Base station with 7245 serial interface boards
# Datastring 7001/6021
#
# BS, 2013/05

ntpq="/usr/bin/ntpq"

# get timecode variable, received from the clock
eval `$ntpq -c 'cv 0 timecode'`

function quit {
	case "$2" in
	0)	echo "OK: $1"
		exit 0
		;;
	1)	echo "Warning: $1"
		exit 1
		;;
	2)	echo "Critical: $1"
		exit 2
		;;
	3)	echo "Unknown: $1"
		exit 3
		;;
	esac
}

function clockstat {
	# Status nibble from hex
	hex0=0000
	hex1=0001
	hex2=0010
	hex3=0011
	hex4=0100
	hex5=0101
	hex6=0110
	hex7=0111
	hex8=1000
	hex9=1001
	hexA=1010
	hexB=1011
	hexC=1100
	hexD=1101
	hexE=1110
	hexF=1111

	eval statnibble='hex$1'
	snibble=${!statnibble}

	case ${snibble:0:2} in
	00)
		textstatus="time/date invalid"
		exitcode=2
		;;
	01)
		textstatus="crystal operation"
		exitcode=1
		;;
        10)
                textstatus="radio operation"
		exitcode=0
		;;
	11)
		textstatus="radio operation (high accuracy)"
		exitcode=0
		;;
	esac

	case ${snibble:2:1} in
	0)
		dss="standard time"
		;;
	1)
		dss="daylight saving time"
		;;
	esac

        case ${snibble:3:1} in
        0)
                ann="no announcement hour"
                ;;
        1)
                ann="announcement (ds-st-ds)"
                ;;
        esac

	quit "status hex=\"$1\", bin=\"$snibble\": $textstatus, $dss, $ann" $exitcode
}


# check for complete string, for example: \x028D194223310513\x0a\x0d\x03
# This is from the Hopf 7245 serial interface board
#
# x20 = Space
# x0D = CR (carriage return)
# x0A = LF (line feed)
# x02 = STX (start of text)
# x03 = ETX (end of text)
#
if [[ $timecode == \\x02*\\x0a\\x0d\\x03 ]];
then
	clockstat ${timecode:4:1}
else
	quit "Timecode not complete" 3	# return Unkown status
fi</code>
=====Troubleshooting=====
  * Show peer status: <code>ntpq -p</code>
  * Show timecode from receiver: <code>ntpq -c 'cv 0 timecode'</code>
  * Show client list (max. 600): <code>ntpdc -n -c monlist

## ntp 2.4.7 removed monlist in favour of ntpq's mrulist
ntpq -c "mrulist"</code>


{{tag>[hardware alix ntp]}}