3.1 KiB
CAN Bus
The Kumquat offers two terminal blocks to access the isolated CAN-FD interface onboard. The following document describes how you can use SocketCAN to evaluate this bus.
SocketCAN provides a set of utilities for working with Controller Area Network (CAN) interfaces on Linux systems.
Connector Pinout Description
| Location | Description |
|---|---|
| X2.1 | CAN High |
| X2.2 | CAN Low |
| X2.3 | Shield |
| Location | Description |
|---|---|
| X3.1 | CAN High |
| X3.2 | CAN Low |
| X3.3 | Shield |
Prerequisites
Before you begin, ensure you have the following:
- 120R Termination Resistor
- Secondary CAN Interface on another Computer using SocketCAN
Hardware Setup
Connect the Termination Resistor to CAN-H and CAN-L onto on of the two CAN-Connectors on the Kumquat.
Connect your Computer's CAN-Interface to the other CAN-Connector on the Kumquat.
Configuring and Setting Up SocketCAN Interface
Configuring Bitrate
To configure the bitrate of the CAN interface, use the ip command with the link option:
ip link set can0 type can bitrate 500000
This command sets the bitrate of the can0 interface to 500 kbit/s. Adjust the bitrate value as per your requirements.
Setting Interface Up
To bring the CAN interface up, use the ip command:
ip link set can0 up
This command activates the can0 interface and makes it operational for communication.
Checking SocketCAN Interface
Checking Interface Status
To check the status of your SocketCAN interface, use the ip command:
ip -details link show can0
This command displays detailed information about the can0 interface, including its status and configuration.
Checking CAN Interface Statistics
To view statistics for the CAN interface, use the ip command with the stat option:
ip -details link show can0 stat
This command provides statistics such as the number of transmitted and received frames, error counts, and interface state.
Sending and Receiving CAN Frames
Sending CAN Frames
To send CAN frames using SocketCAN, you can use the cansend command:
cansend can0 123#1122334455667788
This command sends a CAN frame with ID 123 and data 1122334455667788 on the can0 interface.
Receiving CAN Frames
To receive CAN frames, you can use the candump command:
candump can0
This command continuously monitors the can0 interface and prints received CAN frames to the console.
Analyzing CAN Traffic
Filtering CAN Frames
You can filter CAN frames based on their ID using the candump command with filters:
candump can0,123:7FF
This command only displays CAN frames with ID 123 on the can0 interface.
Analyzing CAN Traffic with Wireshark
To analyze CAN traffic using Wireshark, first, capture CAN frames using candump and save them to a file:
candump can0 > can_traffic.log
Then, transfer the log file to a system with Wireshark installed and open it for analysis.