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