MoTi

moTi

This project is co-funded by the European Union Agency for the Space Programme under the Fundamental Elements Grant EUSPA/GRANT/02/2024

Table of Contents

• Introduction
• What is a moTi?
  • Can I buy it?
• What is a Time Card?
• What is a Mosaic-G5 T?
• Who is Septentrio?
  • Why open-source?
• Disclaimer
• Deliverables
  • M.2 Form Factor
• User Documentation
  • System Setup
    • Boot Linux
    • Check the GNSS Status (Satellite Time)
    • Output the PPS and Clock
    • Use the PHC from Linux
    • When the Card is Installed and Running
    • If Something Goes Wrong
• Design Documentation
  • Ordering Mosaic
  • Board Connections and Indicators
    • Pinout for M.2 Key B Connector
    • USB 2.0
    • UART
    • PPS Out
    • Event 1 (PPS IN)
    • LED D1
    • Antenna Connector

Introduction

What is a moTi?

moTi is a timing module that provides accurate and reliable synchronisation signals for time-sensitive systems. It is based on a standardised M.2 form factor that can be easily integrated into compatible carrier boards such as the Open Compute Project (OCP) Time Card. This board receives precise timing information from Septentrio’s mosaic-G5 T GNSS (Global Navigation Satellite System) module. It then generates synchronisation outputs such as Pulse Per Second (PPS) and Time of Day (ToD) data. These signals are then used to synchronise services, in network interface cards (NICs), and other hardware in data centres and communication systems.

What is a Time Card?

A Time Card is a PCIe card that is designed to plug into a server and provides precision time outputs such as PPS (Pulse Per Second) and ToD (Time of Day). It provides this precise timing to the server’s clock and network hardware, enabling high-accuracy synchronisation using protocols like the NTP or PTP. moTi connects to the Time Card as a timing source, supplying the card with GNSS time signals in standardised form factor.

Originally, it was developed by Meta and released through the Open Compute Project

More information about the Time Card on this link or Github

What is a mosaic-G5 T?

Septentrio mosaic-G5 T is a compact, low-power GNSS timing receiver module with multi-band, multi-frequency capability. Designed for critical infrastructure and other applications where resilient and precise timing is essential, it ensures maximum security and uptime. It tracks all Global Navigation Satellite System (GNSS) constellations and supports both current and future signals.

Who is Septentrio?

Septentrio is a leading company that designs, manufactures and sells high precision and multi-frequency GPS/GNSS receivers for demanding applications. Septentrio products are used in different industries including automotive, marine, construction, rail, machine control, logistics, precision agriculture, geographic information systems (GIS), Unmanned Aerial Vehicles (UAVs), surveying, mapping and scientific development. Septentrio’s receivers constantly deliver accurate and precise GNSS positioning scalable to centimetre-level and designed to perform perfectly in challenging environments.

Septentrio's technology offers high accuracy and reliability thanks to GNSS + algorithms as well as Advanced interference Monitoring and Mitigation (AIM+) This protects your application against jamming (RF interference) and spoofing (malicious attacks).

For more information about Septentrio products go to https://www.septentrio.com/.

Why open-source?

This board is open source to encourage collaboration, customization, and innovation. By making the design files publicly available, developers and engineers can study, modify, and adapt the hardware to fit their specific applications, reducing development time and cost. It also promotes transparency and avoids vendor lock-in, allowing users to fully understand and control the design.

Disclaimer

This project is offered as-is. The main interfaces have been tested, but the design has not been fully checked or approved by the author or Septentrio. You are responsible for how you use it in your own projects. For guidance on working with Septentrio’s GNSS mosaic modules, we suggest reaching out to Septentrio directly.

Support website: https://www.septentrio.com/en/support

Deliverables

This open-source project contains the following files for designers, producers and integrators around Septentrio's mosaic modules.

M.2 form factor

The M.2 form factor provides a compact interface for expansion cards.The moTi board is M.2 Key B connector, but it can also fit into some Key M or B+M slots. B+M slots are designed with extra notches so they accept both Key B and Key M modules, allowing flexibility in installation. This means your Key B board can interconnect with a Key M-compatible slot as long as it’s a B+M slot, ensuring proper electrical connections and compatibility.

User documentation

System Setup

Before you physically install anything:

• Make sure you have a free PCIe slot
• Make sure your BIOS supports Virtualization/IOMMU for Linux use
• You must connect the GNSS antenna to its SMA connector before inserting the Time Card.

Boot Linux

Boot Linux with the Time Card inserted.

If your Linux system uses the Kernel 5.15 or newer the Time Card driver is already included. So the kernel loads the driver automatically.

The devices are exposed by the driver like:

/dev/ptpX -> PHC device

/dev/ppsY -> PPS pulse signal

/sys/class/timecard/ocp0/-> status and attributes

These are the time interface paths in the OS.

Command example to see the devices:

ls -l /sys/class/timecard/ocp0/

This will show many devices including GNSS, PPS, PHC clock and atomic clock serial

Check the GNSS status (satellite time)

Once Linux has detected the Time Card:

• GNSS time is usually on a serial port like /dev/ttyS7 or similar.
• You can run gpsd or a tool like cgps to check the satellite status.

For example:

gpsd /dev/ttyS5

• To make sure GPS is sending messages, use tio

tio -b 115200 /dev/ttyS5

• Check if the FPGA time is correct by checking the NMEA

tio -b 115200 /dev/ttyS0

Output the PPS and Clock

available_sma_outputs contains all available outputs

To list available outputs:

cat available_sma_outputs
    10MHz PHC MAC GNSS1 GNSS2 IRIG DCF GEN1 GEN2 GEN3 GEN4 GND VCC

 cat /sys/class/timecard/ocp0/available_sma_outputs 

Output on SMA:

• FPGA PPS

echo OUT: PHC >> sma1

• Atomic Clock PPS

echo OUT: MAC >> sma1

• GPS Module's PPS

echo OUT: GNSS1 >> sma1

Use the PHC from Linux

The PHC (Precision Hardware Clock) device exposed by the driver can be used to sync the Linux system clock

When the card is installed and running

Once everything is configured:

• The Time Card provides accurate time to Linux
• You can serve time to network clients using NTP or PTP
• Your system becomes a Stratum 1 time source

This means your server can act as a time source for the whole infrastructure.

If something goes wrong

• If the driver fails to load: make sure you have a newer Linux kernel
• If /dev/ptp doesn’t show: check BIOS PCIe settings
• If no GNSS: verify if antenna is connected.

These are normal steps to get the Time Card recognized by Linux.

Design documentation

Ordering mosaic

For orders of the mosaic-G5 T, please contact Septentrio

Block diagram

The above block diagram is showing the overview communication between the antenna, receiver and M.2 edge connector.

Board connections and indicators

Pinout for M.2 Key B Connector

USB 2.0 pins USB_D+ and USB_D- When the module is inserted into a card that supports USB pins on its edge connector, the USB interface works just like it would on any other device. It is used for data, configuration, and control. It carries data such as , Time of Day (ToD) for the GNSS, diagnostic messages and firmware update channels. The Time Card will act as the USB host.

UART (Universal Asynchronous Receiver Transmitter) This is a standard serial port using TX and RX pins.

PPS Out timing reference signal output. This supplies high-precision timing references directly into the Time Card clocking system.

Event 1 (PPS IN) This pin detects a pulse from an external device and records the exact GNSS time when the pulse happened. It is connected to the eventB pin of the mosaic-G5 T

LED D1

This LED indicates whether the Module is ON/OFF

Antenna connector

The board provides a U.FL (UMCC) 50 Ω PCB receptacle for connecting an external GNSS antenna. This miniature RF connector is commonly used in compact embedded and wireless systems due to its small size and reliable high-frequency performance.

Connector Details

• Type: U.FL (UMCC) Receptacle
• Impedance: 50 Ω
• Application: External active/passive GNSS antenna connection

Notes

• Use a compatible U.FL/IPX coaxial cable assembly when connecting an antenna.
• Keep RF cable lengths as short as possible to minimize signal loss.
• Ensure the antenna system is properly matched to 50 Ω impedance for optimal RF performance.