# Testing CAN3 in PX4
At this point time (11/11/2024) CAN3 is not enabled to use DronCAN or UAVCAN by default in PX4.\
The port itself is enabled and can be exercised using CANSEND and CANDUMP commands\
\
This tutorial describes how to enable the CAN3 Port on the NXP-VMU-RT117x in PX4-Autopilot, and demonstrates the transmission of CAN Frames between two VMU-RT117x using the can-utils module.
## ITEMS REQUIRED
{% hint style="info" %}
Note: We require 6 USB-A (Female) ports on the host machine for this setup. You may utilize a USB-HUB (USB-A Male to USB-A Female) to get multiple ports on your host machine.
{% endhint %}
## HARDWARE SETUP
The high level overview here is that we want to be able to both program and gain console access to the MR-VMU-RT1176 so we can issue commands. Note that there are other valid ways to get a console, such as through an attached Telemetry radio. Programming may also use MCU-LINK-MR.
Hardware Connections for Reference (Without USB Wires)
CAN3: 4-Pin JST-GH to 4-Pin JST-GH (Twisted CAN Cable) Connection with the CAN3 Port on VMU-RT117x
USB-C Connection with the CAN3 Port on VMU-RT117x
DEBUG: 10-Pin 2x5 Socket-Socket IDC (SWD) Ribbon Cable Connection with the Debug port on VMU-RT117x
Block Diagram for Hardware Connections (Complete)
## SOFTWARE SETUP
### PX4-Autopilot SETUP
```
cd ~
git clone git@github.com:PX4/PX4-Autopilot.git
cd PX4-Autopilot
make px4_fmu-v6xrt menuconfig
```
Select the following options:
1. Device Drivers → CAN Driver Support
2. License Setup → Use components that have GPL/LGPL licenses
3. Application Configuration → CAN Utilities → SocketCAN cansend tool
4. Application Configuration → CAN Utilities → SocketCAN candump tool
{% hint style="warning" %}
In file "\~/PX4-Autopilot/platforms/nuttx/init/imxrt/rc.board\_arch\_defaults", add the line "param set-default -s UAVCAN\_ENABLE 1" after line number 6.
{% endhint %}
cd ~/PX4-Autopilot
make px4_fmu-v6xrt
make px4_fmu-v6xrt_bootloader
Successful Build Output for px4_fmu-v6xrt
Successful Build Output for px4_fmu-v6xrt_bootloader
### FLASH PX4-Autopilot on VMU
{% hint style="danger" %}
For simplicity, connect only one setup at a time with your host machine, i.e. only 1 VMU-RT117x + Pixhawk Debug Adaptor + J-Link EDU MINI.
Alternatively, you may connect both the setups simultaneously and select the appropriate J-Link when running JLinkExe command.
{% endhint %}
{% hint style="info" %}
Note: The following steps need to be run once for each of the two VMU-RT117x.
{% endhint %}
Open a new shell and perform the following steps for flashing PX4-Autopilot on VMU-RT117x.
{% code overflow="wrap" fullWidth="false" %}
```
cd ~/PX4-Autopilot
JLinkExe
connect
MIMXRT1176XXXA_M7
S
4000
loadbin boards/px4/fmu-v6xrt/extras/px4_fmu-v6xrt_bootloader.bin 0x30000000
loadbin build/px4_fmu-v6xrt_default/px4_fmu-v6xrt_default.bin 0x30020000
```
{% endcode %}
Setting up J-Link for Flashing VMU-RT117x
Successful output for Flashing VMU-RT117x
## EXECUTION STEPS
Get the serial shell of the two VMU-RT117x on your host machine.
{% hint style="warning" %}
Note: Baudrate for the serial console is **57600**.
{% endhint %}
Execute `"`**`candump can2`**" on one shell and "**`cansend can2 123#1234567890`**" on the other.
---
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