2. V2.5.0 GNSS (NEO-M8N) MAG BARO hardware

This page covers hardware-specific details of GNSS module witch also includes magnetometer and barometer. For general information, see 1. General, for software related details see Cyphal interface or DroneCAN interface.

View	Top	Bot

2.1. Features

• Concurrent reception of GPS, GLONASS, Galileo and BeiDou
• Centimeter-level accuracy in a small and energy-efficient module
• Easy integration
• Magnetometer RM3100 (opens new window)
• Baro BMP280 (opens new window)
• 2 JST SM04B connectors compatible with Dronecode Autopilot Connector Standard (opens new window)
• 1 MOLEX (opens new window) non standart connector
• GNSS module NEO-M8N (opens new window)
• RHCP Ceramic GPS Antenna (1461680001) (opens new window)

2.2 Wire

Schematic features. Schematic can be provided via issue.

Connectors

The node has 3 connectors which are described in the table below.

№	Connector	Description
1	CAN1, CAN2	Devices that deliver power to the bus are required to provide 4.5–5.5 V (limited by TJA1042 (opens new window) driver operating voltage) on the bus power line, 5.0 V nominal. Devices that are powered from the bus should expect 4.5–5.5 V on the bus power line. The current shall not exceed 1 A per connector.
2	SWD	STM32 firmware updating using programmer-sniffer.
3	CAN3	Can be powered from 5.5 to 30 volts and connected to CAN.
4	UART	Can be used to setup the GPS module
5	CC	Camera capture port can be used to receive external interrupt from camera trigger and send timepulse to payload such as autopilot

Here (opens new window) you can find manufacturer part number of connectors it self and its mates.

Pin configuration and functions

Pin	CAN3	Pin	CAN1, CAN2	SWD	UART	CC
1	Vin	1	5V in	GND	5V	3.3V
2	Vin	2	CAN High	SWCLK	UBX_TXO	TIMEPULSE
3	CAN High	3	CAN Low	SWDIO	UBX_RXI	EXTINT
4	CAN Low	4	GND	3.3V	GND	GND
5	GND
6	GND

Here you can see all connections of MCU.

2.3. Specifications

Mechanical

Scheme is shown on the picture below. CAN model can be provided via email request or issue on github or downloaded on GrabCAD (opens new window).

	Width, mm	Length, mm	Height, mm
Outline	76	61.3	12.3
PCB	76	61.3	1.6

Total weight of device less than XX g.

Housing

The casing can be downloaded from GrabCAD (opens new window) and printed in ABS or PLA plastic. The housing consists of two parts: top and bottom. It can be assembled using M2 L=6-8mm (opens new window) screws DIN 912 (ISO 4762) and Bras Hot Melt Insert Nut (opens new window). The assembled unit can be fixed with double-sided tape or with M2 L=12-20mm (opens new window) screws.

Bill of materials:

Name	Qty	Comment
ABS or PLA plastic
M2 L=6-8mm (opens new window) screws DIN 912 (ISO 4762)	4	In case of double-sided tape mount type
Bras Hot Melt Insert Nut (opens new window)	4
Double-sided tape
M2 L=12-20mm (opens new window) screws DIN 912 (ISO 4762)	4	In case of screws

GNSS Frequency filtering

The GNSS signal reception path consists of:

Name	Part Number (Datasheet)
Antenna	Molex 2042860001 (opens new window)
SAW Filter	TDK B39162B4348P810 (opens new window)
LNA	Infineon BGA524N6E6327XTSA1 (opens new window)

It provides reception, filtering and amplification in the desired frequency range. The satellite signal ranges and bandwidths of the device elements are schematically shown below.

Thus, it can be clearly seen that the device captures the entire upper frequency range of GNSS.

Absolute Maximum Ratings

Parameter	MIN	MAX	UNIT
Vin (HV)	5.5	55*	V
V (LV)	4.5	5.5	V
I max		1.0	A
Operating temperature

*Noted Voltage should be delivered only with current limitation under 2.5 Amp.

Recommended operating conditions

Parameter	Value	UNIT
Vin (HV)	30	V
V (LV)	5	V
I max		A

ESD ratings

Description	Value	UNIT
Human-body model (HBM)	2000	V
Charged-device model (CDM)	500	V

2.4. Integration

Recommended mechanical mounting

Antenna sensitivity is highly dependent on the surrounding environment. Ensure that the antenna is not covered by any conductive material (e.g. carbon fibre) and is located on the top of the vehicle. The antenna should be able to pick up signals from the sky.

Once the magnetometer is used, it is necessary to mount the device in the right way. The typical way to mount it is shown in the picture below.

Connection example diagram

Device can be connected as termination in CAN bus, but in this case resistor R11 (0603, 120 Ohm) sould be plased on PCB.

Typically, the device can be connected directly to standard CAN bus using the CAN3 and CAN2 LV connectors, but it is better to connect using the CAN1 HV connector, as this connection type avoids power supply problems.

2.5. Power Supply Recommendations

Device is designed to operate from an input voltage supply range between 4.5 V and 5.5 V over CAN2 or CAN3 connector, or 5.5 - 30 V from CAN1. This input supply must be able to withstand the maximum input current and maintain a stable voltage. The resistance of the input supply rail should be low enough that an input current transient does not cause a high enough drop that can cause a false UVLO fault triggering and system reset. The amount of bulk capacitance is not critical, but a 47-μF or 100-μF electrolytic capacitor is a typical choice.

2.6. Revision history

View	Version	Description
	v3.0.0 Summer, 2023	The board is on the testing stage. - Migrate to stm32g0 from stm32f103
	v2.5.0 27 Mar, 2023	The latest stable version. - Timepulse and EXTINT pin wired to connector CC and connected to MCU - Slightly increase the board size - Fix UART connector
	v2.3.2 Oct 14, 2022	The version of the board with a small bug on UART connector. It is not on production. - Integrate RM3100 in PCB - Assign SS pin to PA2 - Add UART connector with wrong pinout!!! - Use RGB LEDs instead of address LEDs
	v2.3.1
	v2.3.0 Aug 10, 2021	The first stable version. Do not use it in a new design. - Ingegrage RM3100 - Assign SS pin to PA4 (so RM3100 doesn't work on the lastest firmware) - Address LEDs (so they don't work on the lastest firmware)