TimeStickV2

USB to Ethernet adapter with AX88279 and SMA

The Time Stick USB adapter brings precision timing and advanced network functionality to any platform with a USB port.

In a small form factor, the Time Stick integrates the high-performance AX88279 USB-to-Ethernet controller with precision timing output via an SMA connector.

It’s a powerful tool for building small form-factor PTP (Precision Time Protocol) clients or grandmasters, ideal for time-sensitive networking applications.

Key Features

• SMA for PPS output
  
• 5-pin right-angle connector for GNSS
  
• DIP switch for IO control to SMA
  
• USB 3.0 Type-A connector
  
• RJ45 jack with up to 2.5 GbE support
  

Building the Driver

The following steps have been tested on fresh installs of Ubuntu 22.04.1 LTS (6.8.0-90-generic kernel) and 24.04.02 LTS (6.11.0-29-generic kernel):

1. Visit the official ASIX GitLab repository and download the AX88279_Linux_TOD_Suite.
2. unzip ax88279_linux_tod_suite-main.zip
3. cd ax88279_linux_tod_suite-main
4. unzip ASIX_USB_NIC_Linux_Driver_Source_v3.5.17_251008.zip
5. cd ASIX_USB_NIC_Linux_Driver_Source_v3.5.17_251008
6. make
7. If step 6 is successful, ax_usb_nic.ko will be created in the current directory.

Using the Driver

To install the built driver for use with modprobe:

• sudo make install
  Note: This command will back up the built-in ax88179_178a driver if it exists.

To load or unload the installed driver:

• Load: sudo modprobe ax_usb_nic
• Unload: sudo modprobe -r ax_usb_nic

To check driver info:

• modinfo ax_usb_nic

Manual Driver Installation

To load the driver manually from the build directory: sudo modprobe mii sudo insmod ax_usb_nic.ko To unload the driver manually:

• sudo rmmod ax_usb_nic

To check driver info:

• modinfo ax_usb_nic.ko

Test Scripts

The /Scripts/ directory contains a test script called ptp_setup.sh. This script can be used to quickly configure and run a PTP test with a master/slave configuration.

Script prerequisites

1. sudo apt install net-tools
2. sudo apt install ethtool
3. sudo apt install linuxptp

Once the necessary tools are installed on each Linux machine, execute the script on each machine.

Note: The script assumes you have installed the ax_usb_nic driver via sudo make install after building the driver.

Executing ptp_setup.sh

1. Use ifconfig (or ip addr) to identify the Time Stick V2 network interface on each Linux machine.
2. On the master machine, run: ./ptp_setup.sh -m
3. On the slave machine, run: ./ptp_setup.sh -s Note: Try running both scripts at the same time; otherwise one may time out while trying to ping the other Time Stick.
4. If you have an oscilloscope connected to both Time Sticks with a rising-edge trigger configured on the master, you should see the PPS signals converge as shown:
5. You can stop the script by pressing s then Enter.

For reference, here is the ptp_setup.sh help menu output:

Usage: ./ptp_setup.sh  
    : The network interface (e.g., eth1).
    : 'm' for master, 's' for slave.

Schematics

TimeStickV2 Schematics

DIP Switch Settings

The onboard SMA can be configured as either an input or output via DIP switch settings. Below is a table showing the possible configurations for the DIP switch and the corresponding direction.