Hardware Assembly

Important: Read Before Use!

ESD Sensitivity

The mosaic-T module is sensitive to ESD. Use a proper grounding system to make sure that the working surface and the components are at the same electric potential.

ESD Precaution

As recommended by the manufacturer, we highly recommend that users take the necessary ESD precautions to avoid damaging their module.

iFixit Anti-Static Wrist Strap
TOL-25572

Active Antenna

Never inject an external DC voltage into the SMA connector for the GNSS antenna, as it may damage the mosaic-T module. For instance, when using a splitter to distribute the antenna signal to several GNSS receivers, make sure that no more than one output of the splitter passes DC. Use DC-blocks otherwise.

External Reference Clock

If the switch for an external reference clock is enabled, users must provide a 10MHz input signal. Otherwise, the mosaic-T module will cease to operate, without a clock signal.

USB Programming

The USB connection is utilized for configuration and serial communication. Users only need to plug their mosaic-T Timing GNSS breakout board into a computer using a USB-C cable.

When the board is initially connected to a computer, the module will initialize as a USB mass storage device.
- For Windows PCs, the USB driver can be installed from the mass storage device or the RxTools software suite.
- When the SD card is mounted, this drive will contain the contents of the SD card that is inserted on the board.
Once the USB driver is installed:
- Two virtual COM ports are emulated, which can be used as standard serial interfaces to access the receiver.
- This interface also supports Ethernet-over-USB and the internal web server can be accessed 192.168.3.1.

GNSS Antenna

In order to receive GNSS signals, users will need to connect a compatible antenna.

Tip

For the best performance, we recommend users choose a compatible L1/L2/L5/L-band GNSS antenna and utilize a low-loss cable. Also, don't forget that GNSS signals are fairly weak and can't penetrate buildings or dense vegetation. The GNSS antenna should have an unobstructed view of the sky.

Danger

Never inject an external DC voltage into the SMA connector for the GNSS antenna, as it may damage the mosaic-T module. For instance, when using a splitter to distribute the antenna signal to several GNSS receivers, make sure that no more than one output of the splitter passes DC. Use DC-blocks otherwise.

SD Card

An µSD card slot is available for users to log and store data, locally on the board. Users, will need to insert a compatible SD card and configure the mosaic-T module for data logging.

SD Card Specifications

The mosaic-T module is only compatible with SD cards of up to 32GB, formatted with a FAT32 file system.

Initial Configuration

Before data logging can occur, it is necessary to create a logging stream from the Logging tab of the web interface or using the RxTools software suite. Streams can contain NMEA or SBF (Septentrio Binary Format) data; SBF can contain RTCM and/or RINEX. (see the Data Logging section)

Operation

Data logging can be controlled on the board through either the LOG button or LOG BTN pin.

Pressing the button or pin LOW (< 5s) toggles data logging to the SD card on and off.
Holding the button or pin LOW for more than 5 seconds (> 5s) and then releasing it, will force the board to:
- Unmount the SD card if it was mounted
- Mount the SD card if it was unmounted

Status

The status of the SD card and data stream are indicated on the LOG LED and pin.

LED	Pin	Status
Off	Low	SD card not present or unmounted
On	High	SD card present and mounted
Blinking	Pulses	Data logging activity

Standby Mode

When Standby mode is initialized, the module terminates all running processes and unmounts the external SD card to avoid any log file corruption (see the Power Modes section).

JST Connector

The JST connector on the Timing GNSS board, breaks out the COM3 UART port of the mosaic-T module.

Pin Connections

When connecting the mosaic-T Timing GNSS breakout board to another device through the JST connector, users need to be aware of the pin connections and voltage ranges of the products. Below, is a diagram of the pin connections for the 6-pin JST GH connector and a table of the connections for our radio transceivers that users can reference.

JST pins — The pin connections of the JST connector on the mosaic-T Timing GNSS breakout board.

Pin Number	1 (Left Side)	2	3	4	5	6 (Right)
Label	V - Triband 5V - Radios	RX - Triband/SiK RXI - LoRaSerial	TX - Triband/SiK TXO - LoRaSerial	C - Triband CTS - Radios	R - Triband RTS - Radios	G - Triband GND - Radios
Function	Voltage Input - Triband: 3.5 to 5.5V - SiK: 5V - LoRaSerial: 3.3 to 5V	UART - Receive	UART - Transmit	Flow Control Clear-to-Send	Flow Control Ready-to-Send	Ground

Breakout Pins

The PTH pins on the mosaic-T Timing GNSS board are broken out into 0.1"-spaced pins on the outer edges of the board.

New to soldering?

If you have never soldered before or need a quick refresher, check out our How to Solder: Through-Hole Soldering guide.

How to Solder: Through-Hole Soldering

Headers

When selecting headers, be sure you are aware of the functionality you require.

Hookup Wires

For a more permanent connection, users can solder wires directly to the board.

Soldering wires to the mosaic-T Timing GNSS breakout board.

External Oscillator

In order to create a GNSS disciplined oscillator, the mosaic-T module needs a 50Ω, 10MHz sinusoidal signal from tunable oscillator and a microcontroller to fine-tune the adjustments.

Warning

When the switch controlling the source of the reference clock is set to EXT, users must provide a 10MHz input signal. Otherwise, the mosaic-T module will cease to operate, without the clock signal. Additionally, the module should be powered off when switching between frequency reference sources; or the module will need to be reset after.

External clock — Connecting an external reference clock to the mosaic-T Timing GNSS breakout board.

Info

To convert the external reference clock into disciplined oscillator, users will also need a controller to:

Read the clock bias from the mosaic-T module's SBF messages
Adjust the frequency of the external clock signal

Unlike traditional approaches, this configuration does not require any external hardware to measure the time delay. Once the clock bias reaches zero, the oscillator's time scale will be aligned with the GNSS time. For time synchronization applications, users can also implement a third-party synchronization service in the mosaic-T module's configuration. This will allow all systems to not only be aligned with the GNSS time, but also synchronized together.