Linux and PEAK-System's CAN Interfaces

Drivers Included in Linux Kernel

Key Features

• Out-of-the-box usage, suitable for most cases
• Part of the Linux mainline kernel, classic CAN since 3.2 (peak_pci), CAN FD since 4.0 (peak_usb)
• CAN channels are handled as network devices (netdev)
  
  

Check: Are CAN drivers part of your Linux environment?

Open a terminal and type:
grep PEAK_ /boot/config-`uname -r`

All PEAK drivers are listed (y = included in kernel, m = separate module) but this may not work in every Linux environment.

Check: Is the CAN device initialized?

Open a terminal and type: lsmod | grep ^peak

If, for example, a USB-based CAN interface from PEAK is connected and initialized, the output will be at least one line starting with peak_usb.

Driver Package for Proprietary Purposes

Key Features

• Contains sources for chardev and for netdev drivers
• Monolithic driver in contrast to mainline SocketCAN environment with several drivers
• Must be compiled for the target system
• Can be build for real-time Linux extensions like Xenomai or RTAI (RTDM)
• Enables the use of PCAN-Basic Linux API calls (not possible via SocketCAN)
• Provides extra information like the bus load (depending on used CAN interface)
• Support of specific hardware features
• True hardware time stamps with handling of clock drifts
• Mainline kernel drivers are blacklisted when using the PCAN driver

When to Use the Package

• Your CAN application relies on PCAN-Basic for Linux API (based on chardev driver).
• The Kernel you run is too old to include one of the peak_* mainline drivers you need.
• The Kernel you run includes peak_* mainline drivers that are out-of-date or might contain issues.

Linux Real Time drivers for PEAK-System PC CAN/CAN FD interfaces

Since the CAN bus is a real-time network then it obviously may need of a real-time system. PEAK-System offers several solutions to support its interfaces in different real-time environments based on the Linux kernel.

But, first:

• "real-time" does not mean "faster" but means "lower and stable latency". Response times may even be a little longer than in a standard Linux kernel, but they will always be the same.
• because its nature is to be a packet-oriented protocol, USB is not supported in real-time. The received frames are received in the USB interface which will decide by itself when to transmit them to the host.

As in the standard Linux environment, the choice of the solution depends on the desired application interface: in standard Linux, if the choice is made according to the chardev or netdev interface, in the real-time world, it is made according to the RTDM or RT-socket-CAN interface. Whatever the chosen interface, the PEAK-System software offer will provide an adapted solution. The table below summarizes this offer:

Linux-RT

Linux-RT is the real-time version of the Linux Kernel that brought real-time facilities to the standard Kernel (see https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/). Applications don't care about it ; real-time is entirely handled by the patched Kernel.

Xenomai

Xenomai is a living project that regularly proposes real-time extensions to the various longterm Linux kernels, for different hardware architectures like ARM, PPC or x86 (see https://source.denx.de/Xenomai/xenomai/-/wikis/home).

Xenomai 3.1 Mercury is not supported here since it is a simple Xenomai interface (skin) to a Linux-RT patched Kernel.

Xenoma 3.1 Cobalt co-kernel is the hard real-time version of Xenomai. Like RTAI, it implements the Real Time Driver Model interface the RT version of the "pcan" driver supports when it is built with "make xeno". Xenomai 3.1 also includes the support of the real-time socket for the CAN bus (aka "RT-Socket-CAN"). With the driver "xeno_can_peak_pci", the RT-Socket-CAN core natively includes support of all the PCI/PCIe CAN 2.0 interfaces of PEAK-System. At the time this note is written (2021/05/06), the PCIe CAN FD interfaces are supported by the driver "xeno_can_peak_pciefd" from the git version of Xenomai (see https://xenomai.org/gitlab/xenomai), in CAN 2.0 mode *ONLY* (CAN FD is not yet supported by the RT-Socket-CAN core).

To take advantage of real-time under Xenomai, an application must be compiled and linked with the real-time libraries that offer access to the real-time facilities added by the Xenomai extension. That's the reason why the pcan library (which encapsulates the calls to the kernel entry points) must be compiled in real-time mode too.

Finally, as shown in the above table, RT-Socket-CAN is not supported by the "pcan" driver.

RTAI

RTAI is another Linux kernel extension coming with user libraries, but doesn't seem to be very much alive for a few years now, the latest version 5.1 dating from February 2018. It also supports different hardware architectures like ARM, PPC, x86 and m68k (see https://www.rtai.org/). It also includes the support of RTDM.

Unlike Xenomai, RTAI doesn't propose any native support of real-time CAN sockets. Therefore, the RTDM version of the "pcan" driver and its library (built with "make rtai") is the only way to take advantage of the benefits brought by real-time under RTAI when using the PC CAN interfaces of PEAK-System.

PCAN-Basic for Linux

API for Connecting to CAN and CAN FD Buses

We provide the PCAN-Basic API to allow the development of your own CAN applications for Linux. Programmers can use the languages C++, Java, and Python 3.x. More information about PCAN-Basic is available at its product web page.

System requirements: This API requires the chardev driver. Please use the Driver Package for Proprietary Purposes.

PCAN-View for Linux

Software for Displaying CAN and CAN FD Messages

PCAN-View is a simple CAN monitor software for receiving and transmitting CAN and CAN FD messages. PCAN-View for Linux is based on the NCurses library.

System requirements: This software requires the chardev driver. Please use the Driver Package for Proprietary Purposes.

How to install PCAN-View via repository

Installing software through repository needs first to register the repository only once. Next to the first installation of the software, there is nothing you have to do, except installing available updates when prompted by your system.

Debian-based Linux distributions

Download and install the following file peak-system.list from the PEAK-System website:

$ wget -q http://www.peak-system.com/debian/dists/`lsb_release -cs`/peak-system.list -O- | sudo tee /etc/apt/sources.list.d/peak-system.list

Note: If the lsb_release tool is not installed on your Linux system then replace `lsb_release -cs` by the name of your Linux distribution. For example:

$ wget -q http://www.peak-system.com/debian/dists/wheezy/peak-system.list -O- | sudo tee /etc/apt/sources.list.d/peak-system.list

Then, download and install the PEAK-System public key for apt-secure, so that the repository is trusted:

$ wget -q http://www.peak-system.com/debian/peak-system-public-key.asc -O- | sudo apt-key add -

To install pcanview-ncurses next, do:

$ sudo apt-get update
$ sudo apt-get install pcanview-ncurses

The supported architectures are summarized in the table below:

	amd64	i386	arm64	armhf	ppc64el
Ubuntu:
Trusty 14.04 LTS
Xenial 16.04 LTS
Bionic 18.04 LTS
Cosmic 18.10
Disco 19.04
Eoan 19.10
Focal 20.04 LTS
Groovy 20.10
Hirsute 21.04
OpenSUSE Tumbleweed	see Xenial
Debian:
Wheezy 7.11
Jessie 8.11
Stretch 9.9
Buster 10