Several gotchas might prevent your Open Timecard Mini from operating correctly. Here is a list of the usual suspects.
DIP-switches incorrectly set (V1 or Base board)
It is possible for the switches on the timecard mini baseboard to become caught in between settings and may need a slight nudge towards their destination to complete or break the circuit.
Pi Not Booting/No HDMI Output
Suppose the first dipswitch of the baseboard is set to ON. In that case, the Raspberry Pi CM4 will not attempt a regular boot from the eMMC (onboard storage / microSD). It will instead present itself as a USB device accessible via the micro-USB port labelled eMMC boot (this is typically used to flash the eMMC or SD card).
No serial console is available.
Incorrectly set switches may interfere with console access. See this article for a guide to the correct DIP switch settings for your use case, and make sure you have them set correctly. (More on serial console access is below.)
CM4 not present
If using the Timecard Mini without a Raspberry Pi CM4 (a perfectly valid use-case) then DIP switches 2-5 must be set to ON.
Loose Cables
The UF cables connecting the SMA bulkhead on the exterior of the metal bracket to the ports on the GNSS module can become disconnected, so check to make sure the cables are firmly attached.
License related issues
Stop timebeat as follows:
systemctl stop timebeatand then run it with
/usr/share/timebeat/bin/timebeat -c /etc/timebeat/timebeat.yml -eand watch the output for license-related messages:
No license found
Cannot read license key file: open /etc/timebeat/timebeat.lic: no such file or directory
License is invalid
License expired/not running in Enterprise mode
Timebeat will not run correctly without the right license. If you see this output after starting timebeat up, then the license is not running in Enterprise mode and will likely not do what you want:
2029-02-02T00:00:06.051Z INFO [License Manager] logging/external.go:94 License verified. Timebeat feature set: free
2029-02-02T00:00:06.051Z INFO [License Manager] logging/external.go:94 License issued to [email protected] (Your Name)
2029-02-02T00:00:06.051Z INFO [License Manager] logging/external.go:94 Enterprise features expired on 1985-10-26 01:21:00 +0000 PST
If you have this problem, obtain a free license for Timebeat here.
Satellite constellations not visible / antenna problems
No antenna connected
When you run the following commands from the host machine or when logged into the Raspberry Pi CM4:
systemctl stop timebeat
apt-get install minicom
minicom -D /dev/serial0
hit the keys: <CTRL-A> Z P C <ENTER> (to set the baud rate to 9600)
The output should look, more or less, like this:
$GPGSV,2,2,08,09,42,200,48,17,39,234,47,19,44,263,27,28,15,035,26,161 $GPGSV,2,1,05,11,01,307,,12,05,325,,21,05,138,,25,02,002,,06F$GPGSV,2,2,05,25,02,002,,057 $GAGSV,2,1,05,05,38,203,45,09,71,105,23,11,19,137,13,34,52,302,24,779$GAGSV,2,2,05,36,69,155,30,74E $GAGSV,1,1,04,04,27,051,,15,03,311,,21,03,013,,27,05,325,,077$GBGSV,4,1,13,06,24,041,17,09,33,055,15,11,25,171,26,14,81,234,40,176 $GBGSV,4,2,13,16,21,037,26,21,18,062,27,26,07,100,16,27,11,322,27,17B$GBGSV,4,3,13,28,49,289,20,33,52,241,38,39,14,031,17,42,70,065,32,176 $GBGSV,4,4,13,43,43,193,48,143If the output looks similar to this:
$GNRMC,144311.00,V,,,,,,,210823,,,N,V*11
$GNVTG,,,,,,,,,N*2E
$GNGGA,144311.00,,,,,0,00,99.99,,,,,,*7A
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,1*33
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,3*31
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,4*36
$GNGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99,5*37
If so, the antenna is likely disconnected, or no satellites are visible. Antennas do not work reliably indoors, although they may work intermittently.
If Timebeat runs while you try to do this, you will see distorted output, so stop Timebeat first.
Cable Errors
If you want PPS to work when using a CM4, an RJ-45 cable must be connected. Additionally, if you don't have a cable plugged in when the server is configured to serve PTP, you will see unexpected behaviour and/or error messages.
Configuration Issues
When commencing testing, the CM4 configuration in /boot/cmdline.txt and /boot/config.txt should be left unaltered. If changes are made to these files, a reboot is required. Additionally, starting with the CM4 SD card image available at https:.//timebeat.app is highly advisable.
Additionally, the configuration file at /etc/timebeat/timebeat.yml requires the correct configuration for your use case. See our guides for examples of how you can make it work as you would like.
Interference Mode Active
If a service is running that sets the system clock or PHC independently of Timebeat, then Timebeat may, by default, run in “Interference Mode.” Possible culprits for this are timesyncd, ptp4l, chrony, and ntpd.
To see which services are running at the current time, use:
systemctl -type=service -state=running To stop them use:
systemctl stop <servicename>
To stop and disable them, use:
systemctl disable <servicename>--now
No Serial Port Access
After confirming the DIP switches are set correctly
The upstream kernel MaxLinear driver is required to access the GNSS serial port; however, it may not be included in your current build.
dmesg | grep ttyShould yield a result something like:
[ 5.730290] 0000:82:00.0: ttyS[3] at MMIO 0xc8000000 (irq = 69, base_baud = 7812500) is a XR17V35X[ 5.744865] 0000:82:00.0: ttyS[4] at MMIO 0xc8000400 (irq = 69, base_baud = 7812500) is a XR17V35Xlspci | grep XR17V35XShould yield:
82:00.0 Serial controller: Exar Corp. XR17V3521 Dual PCIe UART (rev 03)
If the driver is not installed, it can be found in the upstream kernel source.
cd /usr/src/kernels/kernel-versionmake menuconfigThen search for SERIAL_8250_EXAR for the requisite modules to include and make sure they're enabled.
make modules ; make modules installinsmod /usr/lib/modules/6.0.7/kernel/drivers/gpio/gpio-exar.ko /usr/lib/modules/6.0.7/kernel/drivers/gpio/gpio-exar.ko