Overview USB-CAN adapter (SYS TEC USB-CANmodul1)

As you know, there are no computers with CAN interfaces on the market. But all desktop computers and LapTop(s) have USB. In this regard, to debug equipment with CAN, all sorts of USB-CAN adapters are needed. One of these is a German gadget SYS TEC USB-CANmodul1

A bit of theory about the CAN interface

CAN is a two-wire differential serial half-duplex interface for transmitting binary data between electronic PCB boards. The cable most often used is one shielded twisted pair of wires: CAN_L, CAN_H.

A CAN power line at a minimum bit rate of 10 kbit/s can reach as much as 5 km. At a maximum bit rate of 1 Mbit/s – 40 meters.

The main advantage of the CAN interface is the resolution of collisions without loss of bit rate. If two nodes start transmitting packets, the device with the lower ID will transmit.

CAN defines two layers of OSI-7 modules: physical and link. That is, CAN also determines the binary structure of the packet in the cable. The CAN packet contains variables such as packet ID, 8 bytes of data, packet length, 15-bit checksum, ACK confirmation bits.

At the application level, they usually do J1939, CanOpen, UDS and other protocols.

The CAN interface is implemented in hardware in many microcontrollers as a digital electrical circuit inside the SoC. These are microcontrollers from STm, Artery, etc.

I have personally seen the CAN interface used in cars, RFID readers for miners, trucks, buses, CubeSat(s) and space probes.

Hardware

There is a USB-CAN adapter. Called SYS TEC USB-CANmodul1. This is a product of the German company SYS TEC electronic. This is what he looks like in real life.

The product is quite expensive, about 39597 RUR. Here is the pinout of the main CAN connector.

Pinout of the DB-9 plug connector in the photo:

If you analyze the spec, you can understand that inside the black plastic sarcophagus there should be something like this electronic filling:

When nothing is transmitted, the voltage on the CAN-L CAN-H wires is 2.1….2.24V. As a result, the voltage difference is zero.

What do you need from the documentation?

What equipment do you need?

What software do you need?

If you plug it into NetTop PC right out of the box, the Windows 10 operating system will not recognize it.

In this regard, you need to obtain administrator rights and install the driver and CANinterpreter utility from the vendor. Without this software, the SYS TEC USB-CANmodul1 adapter can only be sold for scrap.

By default, CANinterpreter is installed here
C:\Program Files (x86)\SYSTEC-electronic\CANinterpreter
C:\Program Files (x86)\SYSTEC-electronic\USB-CANmodul Utility Disk

When the driver is installed in the device manager, the adapter will be displayed like this

Before working directly with the USB-CAN adapter, it must be initialized. Initialization consists of selecting an instance and assigning a bit rate to it.

The CANinterpreter utility scans raw CAN bus traffic. Shows both CAN packets received externally and CAN packets sent by itself. You can analyze the communication session. This view can be called a waterfall. Packages are pouring from bottom to top.

However, to save monitor space, you can also view statistics on ID packets in the CANinterpreter program

Most likely you are developing firmware for an electronic CAN board and microcontroller. To catch CAN packets on the MCU side, you will need UART-CLI.

Also in UART-CLI you can directly ask the microcontroller to emit some specific CAN packet. Like this.

On the microcontroller side in the UART-CLI you can clearly see how CAN packets arrive from the CANinterpreter utility.

You can also see how the microcontroller sends packets with ID: 0x7FF to the CAN bus

Here are CAN packets with ID: 0x7FF received by the CANinterpreter utility on the host PC.

CAN bus is working.

When a packet passes through the CAN bus, the green LED (traffic) blinks 2 times. If you disconnect the CAN bus from the adapter, the red LED (state) will blink at a frequency of 1Hz.

Project ideas with USB-CAN adapter

1–You can reverse engineer vehicle CAN bus traffic. Try to find some meaningful signals in traffic in response to external stimuli. For example, pressing the gas or brake pedal, turning the steering wheel, etc. Then sell this data to car sharing offices and taxi companies.

2–You can debug on-board equipment via CAN. You can control the electronic boards inside the units: update firmware, read diagnostics, write configs.

3–You can make a text messenger.

Results

We learned how to use the SYS TEC USB-CANmodul1 device and software for it.

Dictionary

URLs

https://www.systec-electronic.com/en/products/interfaces-gateways-amp-controls/sysworxx-usb-can-module1