PX4 Firmware Guide

This chapter describes the points to be aware of when running PX4 firmware on the X25 EVO. The PX4 docs has the complete PX4 guide.

Loading firmware

There are two methods for firmware flashing: online flashing and local flashing. You can choose based on your needs.

Write firmware online:

• Download and run the LGC Ground Station, then click the LGC icon.
• Navigate to Drone Settings → Firmware, and connect the controller to the computer via USB.
• Select the required "PX4 Pro vxxxx" version and click Confirm.
• After the loading is complete, if no operation is performed, the controller will connect automatically after a dozen seconds.

Local Flashing (Custom Firmware)

• Download the X25 EVO Local Firmware to your local computer.
• Enter the firmware flashing settings, check Advanced Settings, and select the version as Custom Firmware.
• In the pop-up window, select the downloaded local firmware file to complete the flashing.

Serial Mapping

UART	Device	Port
USART1	/dev/ttyS0	GPS1
USART2	/dev/ttyS1	GPS2
USART3	/dev/ttyS2	Debug Console
UART4	/dev/ttyS3	UART4
UART5	/dev/ttyS4	TELEM2
USART6	/dev/ttyS5	RC
UART7	/dev/ttyS6	TELEM1

Power Module Settings

The X25 EVO comes standard with a PMU2 Lite power module, which supports a 20-70V input and a maximum current of 220A. It can be directly connected to the X25 EVO's Power C1/C2 ports. Once connected, power on the controller without configuring any parameters.

If you modify its settings, you need to set the following parameters and restart the controller after writing.

• Set the UAVCAN_ENABLE parameter to Sensors Automatic config.
• Set the UAVCAN_SUB_BAT parameter to Enabled.

NOTE

Analog power modules are not recommended due to poor accuracy and large temperature drift. It is recommended to use CAN power modules such as PMU2 Lite (with factory calibration and temperature compensation) or CAN smart batteries.

Rated Voltage

The X25 EVO supports triple power redundancy. Pay attention to the voltage range of each interface.

Power Rail	Type	Voltage Range
POWER C1	DroneCAN/UAVCAN Battery Interface	10V - 18V
POWER C2	DroneCAN/UAVCAN Battery Interface	10V - 18V
USB	USB Input	4.75V - 5.25V

TIP

Unlike other controllers, the X25 EVO's POWER C1/C2 ports do not support 5V input, only 10V-18V voltage input. For the default package, the PMU 2lite converts the 20-70V voltage to 15V to power the X25 EVO.

Ethernet Configuration

The X25 EVO supports LAN connection via Ethernet. Devices in the LAN must be on the same IP network (same subnet) to ensure each device has a unique IP address and can communicate with other devices. By default, Ethernet uses DHCP for automatic IP assignment; if DHCP fails, you need to set the IP manually.

Setting the IP Address

• Connect the controller to the computer using a USB cable.
• Open QGroundControl via the MAVLink Console → Analyze Tools.
• Enter the following commands in the MAVLink Console (to write values to the configuration file)：

 echo DEVICE=eth0 > /fs/microsd/net.cfg
 echo BOOTPROTO=fallback >> /fs/microsd/net.cfg
 echo IPADDR=10.41.10.2 >> /fs/microsd/net.cfg
 echo NETMASK=255.255.255.0 >>/fs/microsd/net.cfg
 echo ROUTER=10.41.10.254 >>/fs/microsd/net.cfg
 echo DNS=10.41.10.254 >>/fs/microsd/net.cfg

• After setting the network configuration, disconnect the USB cable and restart the controller.
• After the setup is complete, the configuration information will be saved in the SD card directory /fs/microsd/net.cfg name=value as follows:

DEVICE=eth0
BOOTPROTO=fallback
IPADDR=10.41.10.2
NETMASK=255.255.255.0
ROUTER=10.41.10.254
DNS=10.41.10.254

Where the values are:

• DEVICE: Interface name. Default is .eth0
• BOOTPROTO: Protocol for getting PX4 IP address. Valid values for proto are: , , (use DHCP but fall back to static address after time, if that fails) dhcp、static、fallback
• IPADDR: Static IP address (used if BOOTPROTO is or static fallback)
• NETMASK: Network mask
• ROUTER: The address of the default route.
• DNS: The address of the DNS server.

Network Connectivity Test

• Open the Windows Command Prompt.
• Enter the command: ping 10.41.10.2

TIP

A response with network latency data indicates that communication is established. A "request timed out" message may mean the IP address is incorrect or communication has failed. For more details, refer to PX4 Ethernet Setup.

Connecting to GCS

Run the LGC Ground Station software. Configure the Ethernet port to transmit MAVLink data.

Parameter	Value	GCS Display	Description
MAV_2_CONFIG	1000	Ethernet	Configure MAVLink to transmit via Ethernet
MAV_2_BROADCAST	1	Always broadcast	Broadcast messages continuously
MAV_2_MODE	0	Normal	Send the "normal" set of MAVLink messages (i.e., the GCS set)
MAV_2_RADIO_CTL	0	Disabled	Disable software restrictions on MAVLink traffic
MAV_2_RATE	100000	100000B/s	Maximum transmission rate
MAV_2_REMOTE_PRT	14550	14550	MAVLink remote port 14550 (for GCS)
MAV_2_UDP_PRT	14550	14550	MAVLink remote port 14550 (for GCS)

• Create a new network connection: Go to Application Settings → Commlinks → Add Connection. Set the connection name, select UDP as the connection type, enter the controller's IP address and port number (14550), then click OK to confirm the creation.

• Once created, select the connection to establish communication.

Firmware Compilation

NOTE

Most users do not need to compile firmware; they can directly flash firmware online via LGC/QGroundControl.

Compilation Command

make cuav_x25-evo_default

Debug Port

The PX4 System Console and SWD run on the FMU Debug port. They can be used with the C-ADB DebugAdapter for debugging configuration.

Pin	Signal	Volt
1 (red)	5V+	+5V
2 (blk)	DEBUG TX (OUT)	+3.3V
3 (blk)	DEBUG RX (IN)	+3.3V
4 (blk)	FMU_SWDIO	+3.3V
5 (blk)	FMU_SWCLK	+3.3V
6 (blk)	GND	GND

Development Guide

• PX4 Source Code Repository
• QGroundControl Ground Station Code Repository
• ArduPilot Development Guide
• Mavlink Protocol
• Droncan Bus Protocol

NOTE

CUAV does not provide technical support for secondary development of firmware or software. For related questions, please read the relevant guides carefully.

More Information

PX4 Docs