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Application

How to use the Time Card

The Time Card is interfaced via sysfs.

Sysfs

To view all the sysfs parameters exposed.

ls /sys/class/timecard/ocp0/

Additional Time Card devices will enumerate as ocpN where N is the device order.

Serial ports and PHC number

Serial ports and PHC number can be found via dmesg or ls -l

Using The Time Card IO

Ouputs

All possible outputs are available via available_sma_outputs,

cat available_sma_outputs

Will display all possible output types such as,

10Mhz PHC MAC GNSS1 GNSS2 IRIG DCF GEN1 GEN2 GEN3 GEN4 GND VCC

A few examples for configuring the output signals,

  1. Output FPGA PPS on SMA
echo OUT: PHC >> sma1
  1. Output Atomic clock PPS on SMA
echo OUT: MAC >> sma1
  1. Output GPS Module's PPS on SMA
echo OUT: GNSS1 >> sma1

Inputs

All possible inputs are available via available_sma_inputs,

cat available_sma_inputs

Will display all possible inputs types such as,

10Mhz PPS1 PPS2 TS1 TS2 IRIG DCF TS3 TS4 FREQ1 FREQ2 FREQ3 FREQ4 None

An example for configuring a SMA input signal,

  1. Input Timestamp on SMA Use a port for time-stamping incoming signals, this configured SMA1 with timestamper-1 TS1.
echo IN: TS1 >> sma1

To read back the timestamped signals, use testptp.

Download testptp source

Source available at these locations

  1. https://www.mjmwired.net/kernel/Documentation/ptp/testptp.c
  2. https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptp/testptp.c

Read timestamped signals

**Note: ** -1 for inifite readings, use a positive number for fixed event count, from Timestamper 1 -i 1 from the Time Card /dev/ptp1

./testptp -d /dev/ptp1 -e -1 -i 1