User guide

Our newest AutoPi CAN-FD Pro device has some new features that are not available on our other devices. This guide will walk you through everything you need to know about the CAN Logging feature on our AutoPi CAN-FD Pro device. Whether you're setting up your first logger or exploring advanced options, we've made it easy to follow and fully customizable to suit your needs.

note

CAN Logging on the AutoPi CAN-FD Pro is different from the Loggers feature available on our other device AutoPi TMU CM4.

What is CAN Logging? CAN Logging captures traffic from your vehicle’s CAN bus using two dedicated interfaces: can0 and can1. These logs can include raw or decoded data, depending on your configuration.

Channels

A channel is a pathway through which the device listens to or communicates on the CAN bus. Most vehicles have one or two CAN buses. The AutoPi CAN-FD Pro supports two channels out of the box: can0 and can1. CAN communication is based on an agreed bitrate (speed of the amount of data processed within 1 second). Think of it like tuning two radios to the same frequency—you need to match speeds to understand each other. If you don’t know the bitrate, no worries. The AutoPi CAN-FD Pro device can automatically detect it by listening and testing.

How to Configure CAN Channels?

By default, can0 and can1 channels are preconfigured with standard values. But you can fully customize them.

Opening the configuration of the CAN channel

• Go to the Devices section.
• Click on the device you want to configure.
• Select the CAN Logging tab.
• Click on the channel you want to edit.
• Click the "Configure" button in the top-right corner.

Configure the CAN channel:

1. Name & Description of the CAN channel

• Name the channel or update the existing name.
• Add a description to clarify its purpose.

2. Enable or Disable CAN channel

• Use the checkbox to turn the channel on or off.

3. Autodetect (How to find the correct bitrate)

• Choose from three detection methods:
  • Any (passive) – Just listens for traffic without sending anything.
  • OBD (active) – Sends an OBD-II request and waits for a response.
  • J1939 (active) – Sends a J1939 request and listens for supported responses.

4. Try Bitrates or Use Fixed Bitrate

• You have two options here:

  • Try Bitrates (Auto Mode): If you're unsure about your vehicle’s bitrate, this is the best choice. The device will automatically scan through a list of common CAN 2.0 and CAN FD bitrates. It opens one channel, listens for about a second, then tries the next—until it locks onto the right one, basically the device tries different bitrates until it finds the one that matches your vehicle.

  • Fixed Bitrate (Manual Mode): Already know the exact bitrates for your CAN 2.0 and/or CAN FD? Just input them directly. This saves time and ensures consistent communication.

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You can reorder the bitrate list and add your own based on your specific setup. Just use the 2 line icon on the left side.

5. Advanced Channel Settings

Under Advanced Settings you’ll find a few more options for extra settings:

• Enable Termination – Adds ~120Ω termination resistance for the CAN bus, often required at the end of a CAN line.
• Allow Changing Interface – Lets the system modify interface settings like bitrate and power state.
• Allow Sending – Enables or disables sending CAN messages through this channel.
• Receive Own Messages – Allows the device to also listen to messages it sends (useful for testing/debugging).

Loggers

A CAN logger records all the CAN bus traffic detected through the can0 and can1 interfaces. This data can be raw or decoded, depending on how you configure the logger.

How to create CAN Logger?

Setting up a CAN logger is easy and flexible. We’ve provided default values for most fields, but you can customize everything to match your specific requirements.

• 1. Basic information:
  • Start by entering:
    • Name – the name you want to give to this logger.
    • Description – optional, but helpful if you want to add details about its purpose.

• 2. Filters: use filters to control which types of CAN frames are logged.
  • Allowed Frame Types: choose from normal, error, and remote frames.
  • Allowed identifier Bits: supports both 11-bit (standard) and 29-bit (extended) identifiers.
  • Pass filters: only CAN frames that match these filters will be logged.
    • To add a new filter, you'll need to specify the identifier bit length, ID, and a mask.

• 3. Decoders: this step allows you to decode raw CAN data using Standard decoder or ASAM decoder.

  • Add Standard decoder:
    1. Decoder name: name your decoder.
    2. DBC File Path: provide the DBC file path.
    3. Select a DBC collection: Select a DBC collection.
    4. Add a DBC collection: automatically add filters for all DBC message IDs.

  Automatically add pass filters for all DBC message identifiers

  • Add ASAM decoder:
    1. Decoder name
    2. DBC File Path
    3. Select a DBC collection
    4. Add a DBC collection

  Automatically add pass filters for all DBC message identifiers

• 4. Outputs

  • Raw data
  • Decoded data

If you enable "show Advanced setttings" in the right top corner, you get access to 1 extra step, frame listeners.

• 5. Frame listeners

note

This feature is still under development. More will come!

How to edit CAN Logger?

Need to make changes to a CAN logger? No problem, it’s super simple. Just follow these steps:

• Go to the Devices section in the menu.
• Select the device you want to work with.
• Click on CAN Logging tab.
• Under Loggers, find the specific logger you’d like to edit.
• Click the three dots icon in the top-right corner of that logger.
• From the dropdown menu, select Edit.
• Make your changes and save when you’re done.

Advanced settings

Our newest AutoPi CAN-FD Pro device has some additional settings that can be modified.

Advanced settings for Disk Housekeeper

• Critical use limit: this setting allows you to set an event based on critical use limit (user customizable). Disk usage percentage that is considered critical and which causes an event to be triggered.
• Enabled: this settings allows you to enable Disk Housekeeper, that prevents your disk from running full with old files. By clicking on True, you enable automatic disk cleanup to prevent the disk from running full. The oldest files will be deleted first.
• Use limit: disk usage percentage which is the limit for when file deletion should begin.
• Use target: disk usage percentage which is the target to reach when deleting files.
• Worker delay: represents delay after startup before performing the first check for files to cleanup.
• Worker interval: represent time period between each check for files to cleanup.

Advanced settings for Output Handler

• At the moment if you want to use AWS S3 Cloud storage as an output handler, you will need to fill out these fields:
  • Worker delay - delay after startup before executing of the AWS S3 sync process.
  • Worker interval - time period between each check of the executing AWS S3 sync process.

Let's keep in touch!

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