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Hardware Overview

Combo Breakout PCB
The Combo Breakout PCB. (Click to enlarge)

The u-blox ZED-F9P NEO-D9S Combo Breakout is a sophisticated yet compact GNSS board. The following is a summary of its features and functions:

  • ZED-F9P - the ZED-F9P is a top-of-the-line module for high accuracy GNSS and GPS location solutions
    • Concurrent reception of GPS, GLONASS, Galileo and BeiDou
    • Multi-band RTK with fast convergence times and reliable performance
    • Centimeter-level accuracy in a small and energy-efficient module

ZED-F9P
The ZED-F9P GNSS module. (Click to enlarge)

  • NEO-D9S - the NEO-D9S is a satellite data receiver for L-band correction broadcast
    • The NEO-D9S can be configured for use with a variety of L-band correction services including u-blox's PointPerfect service
    • It decodes the satellite transmission and outputs a correction stream directly to the ZED-F9P via UART2

NEO-D9S
The NEO-D9S correction data receiver. (Click to enlarge)

  • UART2 TX and RX - the ZED-F9P and NEO-D9S UART2 TX and RX are interconnected (crossed-over) to allow the NEO to feed corrections directly to the ZED
    • The UART2 pins can be isolated if required by opening the TX2 and RX2 jumpers
    • Using UART2 to pass the correction data is recommended, but is optional. You can use UART1 or I2C instead if you want to. Our u-blox Arduino Library has an example which shows how to read the correction data from the NEO-D9S and push it to the ZED-F9P using I2C.

UART2
The UART2 connections. (Click to enlarge)

  • Antenna Power Divider - the breakout has an on-board power divider (antenna splitter) to divide the satellite signals between the ZED and the NEO
    • The connector is SMA female (standard polarity)
    • 3.3V power is provided for an active antenna

Splitter
The antenna splitter (power divider). (Click to enlarge)

  • Dual USB-C connections - one USB-C connector provides a direct connection to the ZED-F9P; the second provides a direct connection to the NEO-D9S
    • The board can be powered via either USB-C connector, or both
    • There is no on-board USB hub. Both ports can be connected simultaneously to the same computer, or different computers if desired

USB Connectors
The two USB-C connectors. (Click to enlarge)

  • LED Indicators - the breakout has four LED indicators:
    • 3V3 Power
    • RTK: Off = No Carrier Solution; Flashing = Floating Solution; On = Fixed Solution
    • GEO: Geofence indication
    • TP: Timing Pulse (Pulse Per Second)
    • Each LED can be disabled by opening the corresponding split pad jumper on the bottom of the breakout

LEDs
The LEDs. (Click to enlarge)

  • Dual Qwiic Connectors - the breakout has two Qwiic (I2C) connectors allowing the breakout to be daisy-chained into your Qwiic project

Qwiic Connectors
The two Qwiic connectors. (Click to enlarge)

  • Back-up Battery - a small rechargeable coin cell maintains the ZED-F9P battery-backed RAM while the power is disconnected

Back-up Battery
The rechargeable back-up battery. (Click to enlarge)

  • Full set of breakout pads - the breakout pads provide full access to the ZED-F9P and NEO-D9S pins
    • I2C
    • UART1
    • UART2
    • External Interrupt
    • Reset
    • Safeboot
    • ZED-F9P: TX_RDY, TP, GEO, RTK
    • Power: 5V and 3.3V

Breakout Pads
The breakout pads. (Click to enlarge)

Board Dimensions

The board dimensions are illustrated in the drawing below. The listed measurements are in inches. The four mounting holes are compatible with 4-40 UNC or M3.0 screws.

Board Dimensions
Board dimensions. (Click to enlarge)

Left Edge Breakout Pads

With the SMA connector oriented to the 'top', the breakout pads down the left side of the board are:

Pad Function
ANT_PWR External antenna power
Cut the ANT_VCC trace and install L1 to enable
EXT_INT_NEO Connected to the NEO-D9S EXT_INT pin
RX1 NEO-D9S UART1 RX Pin
TX1 NEO-D9S UART1 TX Pin
RX2 NEO-D9S UART2 RX Pin
Connected to ZED-F9P TX2 (Open the TX2 jumper to isolate)
TX2 NEO-D9S UART2 TX Pin
Connected to ZED-F9P RX2 (Open the RX2 jumper to isolate)
GND Power Ground (0V)
3V3 3.3V Supply rail
Output of regulator U2 (Can also be used as a power input)
SDA I2C Data
Common to both ZED and NEO
SCL I2C Clock
Common to both ZED and NEO

For more details, users can reference the schematic.

Right Edge Breakout Pads

With the SMA connector oriented to the 'top', the breakout pads down the right side of the board are:

Pad Function
RESET Reset
Active low. Common to both ZED and NEO
EXT_INT Connected to the ZED-F9P EXT_INT pin
TX1 ZED-F9P UART1 TX Pin
RX1 ZED-F9P UART1 RX Pin
TX2 ZED-F9P UART2 TX Pin
Connected to NEO-D9S RX2 (Open the TX2 jumper to isolate)
RX2 ZED-F9P UART2 RX Pin
Connected to NEO-D9S TX2 (Open the RX2 jumper to isolate)
SCL I2C Clock
Common to both ZED and NEO
SDA I2C Data
Common to both ZED and NEO
3V3 3.3V Supply rail
Output of regulator U2 (Can be used as a power input)
GND Power Ground (0V)

For more details, users can reference the schematic.

Right Edge Breakout Pads

With the SMA connector oriented to the 'top', the breakout pads along the bottom edge of the board are:

Pad Function
TX_RDY Indicates the ZED-F9P has data waiting in its I2C TX buffer
TP ZED-F9P Timing Pulse (Pulse Per Second)
GEO ZED-F9P Geofence indicator
RTK ZED-F9P RTK indication
High = No Carrier Solution. Square Wave = Floating Solution. Low = Fixed Solution
5V 5V Power Rail
Can be used as a power input or output (from USB) (Diode protected)
3V3 3.3V Supply rail
Output of regulator U2 (Can be used as a power input)
GND Power Ground (0V)

For more details, users can reference the schematic.

Jumpers

Note

Never modified a jumper before? Check out our Jumper Pads and PCB Traces tutorial for a quick introduction!

How to Work with Jumper Pads and PCB Traces

There are multiple jumpers on the back of the board that can be used to modify how the board functions.

Jumpers
The jumpers on the back of the function board. (Click to enlarge)

  • TX2 - open this jumper to isolate NEO-D9S RX2 from ZED-F9P TX2
  • RX2 - open this jumper to isolate NEO-D9S TX2 from ZED-F9P RX2
    • By default, the NEO-D9S PMP (SPARTN) correction data stream is output directly from NEO-D9S TX2 to the ZED-F9P RX2
    • Opening this jumper will break that connection
    • Correction data can be read from the NEO-D9S and pushed to the ZED-F9P via I2C instead
  • I2C - close this double jumper to connect additional pull-up resistors to I2C SCL and SDA. Not recommended
  • SHLD - the two SHLD jumpers can be opened to isolate the USB-C connector shields from GND. Not recommended, but may help prevent EMI
  • PWR - open this jumper to disable the Power LED
  • RTK - open this jumper to disable the RTK LED
  • GEO - open this jumper to disable the GEO LED
  • TP - open this jumper to disable the TP (PPS) LED

ANT PWR

By default, 3.3V active antenna power is provided on the SMA connector via the NEO-D9S VCC_RF output pin. Power is delivered via a 10 Ohm resistor, to limit the current in case the antenna cable becomes shorted.

If your antenna requires a higher voltage (or current):

  • Isolate VCC_RF by cutting the trace marked by the arrow symbols on the top of the PCB

VCC_RF
The VCC_RF trace. (Click to enlarge)

  • Install inductor L1 - using a 0603 inductor with impedance >500 Ohms at 1.5 GHz

L1
The position of L1. (Click to enlarge)

  • Inject a clean DC supply voltage between the ANT PWR breakout pad and GND

SAFEBOOT

It may be necessary to place the ZED-F9P or NEO-D9S into a "safe boot" state before applying a firmware upgrade.

If this becomes necessary:

  • Disconnect power to the breakout board
  • For the ZED-F9P: connect a jumper wire between the SAFEBOOT ZED test point and GND
  • Reconnect the power
  • Disconnect the jumper
  • Upgrade the firmware using u-center

Repeat for the NEO-D9S using the SAFEBOOT NEO test point.

Jumpers
The two SAFEBOOT test points. (Click to enlarge)

LED Indicators

The breakout has four LED indicators:

  • 3V3 Power
  • RTK: Off = No Carrier Solution; Flashing = Floating Solution; On = Fixed Solution
  • GEO: Geofence indication
  • TP: Timing Pulse (Pulse Per Second)

Each LED can be disabled by opening the corresponding split pad jumper on the bottom of the breakout

Back-up Battery

A small rechargeable coin cell maintains the ZED-F9P battery-backed RAM while the power is disconnected. It maintains the ZED's GNSS Almanac and Real Time Clock.

The battery is recharged slowly whenever 3.3V power is present.

If the battery becomes discharged, connect 3.3V power for at least 48 hours to recharge the battery.

Power Supply and I/O voltage

Both the ZED-F9P and NEO-D9S are 3.3V devices. They operate from 3.3V and all of their I/O pins are 3.3V.

Attention

Do not drive any of the ZED-F9P or NEO-D9S I/O pins using 5V signals. You may damage either or both modules if you do. Use a suitable level-shifter if you want to interface to a 5V development board.

The board has a 3.3V regulator on-board to regulate 5V USB-C power (if present) down to 3.3V.

The options for providing power to the board are as follows:

  • 5V power via one or both USB-C ports
    • Diode protection is provided
  • 5V power via the 5V breakout pin
    • Diode protection prevents the USB-C ports from being reverse-fed
  • 3.3V power via:
    • Either of the Qwiic connectors
    • Any of the 3V3 breakout pins

Current Draw

Worst-case current draw of the ZED-F9P and NEO-D9S combined is 260mA at 3.3V.

Typical current draw of the ZED-F9P and NEO-D9S combined is 100mA.

(These figures exclude any current drawn by an active antenna.)