Questions tagged [can]

CAN stands for Controller Area Network and is a bus often used in automotive applications. It is a two-wire differential protocol and works on baud rates from 10 kbits/sec to 1 Mbits/sec.

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Linearizing multi-star network for home automation

I'm designing a communication network for private home automation. My design goals are: Local wrt network changes. That is, changing one part of the network should not require modification of the ...
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Configuring UART pins on Beaglebone Black for CAN Interface

I have been using a CAN/RS485 Cape for prototyping CAN control of a motor. I am now in the process of bringing up some custom hardware. I have a CAN Transceiver SN65HVD230D on this custom cape that is ...
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CAN Frame Malforming on Oscilloscope

I have a working 500kbps CAN bus between an Arduino Uno and a RaspberryPi. Both are connected to MCP2515/TJA1050 boards from Amazon and communicating over SPI. The RaspberryPi dumps the CAN data via ...
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MCP2551 with STM32 MCU

im learning about the CAN protocol, and bought the transceiver module MCP2551 like this: I made the driver for CAN controller first in loopback mode for debug, im sending the numbers 1,2,3 and 4 with ...
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Compatibility and Interoperability Between CAN Standards

I'm intended to design a CAN system for a automotive scan tool. So, I need to comprise the main CAN standars used nowadays. Searching on the web I found the following options: ISO 11519-2:1994 – Low-...
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CAN bus traffic is destroyed for unknown reason

I am a bit stuck with connecting several STM32F405 with BeagleBone black via CAN bus. Strange things happen when I connect 3 stm32 and 1 BB. I have checked that BB works perfectly with any ...
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77 views

Interoperability between regular and single-wire CAN bus

Is it possible to connect a regular CAN transceiver (ISO 11898-1) to a single-wire CAN bus (SAE J2411) in a compatible way? By "compatible" I mean that the whole system should support valid J2411 bus ...
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125 views

CAN ports on STM32F407G board

The project I'm starting with requires multiple development-boards connected with CAN buses. Is it possible to put two CAN ports on an STM32F407G board?
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466 views

Noise resilient, hot-pluggable communication bus over long cables?

I'm working on a setup, where we need communication between a master device and several slave microcontrollers distributed out in different boxes connected by "long" cat5e cables (3-10 meters) The ...
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1answer
271 views

Interfacing with a truck's internal CAN bus system

I'm currently exploring different ways by which I can communicate with a truck's internal CAN bus system and would like some advice on the most appropriate solution for me. I have overviewed the CAN ...
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668 views

Bus interface for short distances, many device data exchange - CAN, RS485? + characteristic impedance and media capacitance

I ran into some troubles trying to design a wired bus which will connect in about 64 testing devices. My first choice of mind was CAN bus, known of it's reliability and low EMC interference. However, ...
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59 views

Controller Area Network CANIDT

I am learning CAN protocol. It is a dumb question about CANIDT register. What is the link between Tag Identifier and Message Object. Is it arbitrary set by the programmer or is it linked with actual ...
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STM32F429 HAL library CAN_Transmit timeout

I'm having a bit of trouble with the ST32CubeF4 v1.13.0 example of a CAN network. I'm using an STM32F429 discovery board, but I have ported over the CAN network example from the STM324x9_EVAL board. I ...
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106 views

Do you consider this design as an application layer on top of the CAN protocol?

This is a follow up question from my previous question about How do I program 2 CAN nodes to transmit continuously in succession? I'm planning to add another layer on top of the CAN protocol and I ...
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1answer
45 views

How can a single CAN transreceiver be connected to two types of connectors?

I would like to connect a CAN transreceiver to the db9 connector and at the same time CAN line has to go another circuit. Is it possible to use only single transreceiver and have both access from ...
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76 views

CAN Bus Dominant and Recessive?

Why does CAN Bus represents signals with an inverted logic, high voltage for a logic 0 and low voltage for a logic 1? Is there any advantage in doing so?
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CAN Bus Voltage Discrepancy

I’m currently using a sysWORXX USB-CANmodul1 to communicate with a Maxim MAX3051 CAN Transceiver on a custom PCB of mine. I've been having issues with the modul1 losing connectivity with the board. ...
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29 views

Canbus bit stuff Error

I was communicating two stm32f4 discovery board and i wanted to create some failure scenario to take precautions. I shorted CANH & CANL and pulled VCC, GND respectively. But now my both of board ...
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1answer
93 views

NAK in CAN bus for STM32F3 uC

I have a problem with the NAK on the CAN bus. On STM32F303RE I wrote a code for communication via CAN bus with car dashboard (Instrument Panel Cluster). The communication works, I manage to receive ...
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1answer
38 views

Canbus over canberry with raspberry pi two messages together at the same time

Im using a canberry with raspberry pi. Is there any way possible to send two messages at the same time with same id and be received by the other raspberry without any particular chance of getting a ...
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111 views

CAN bus with CANL only?

I'm interfacing a product that operates on a kind of CAN bus. Specifically, it uses the CANL line only. I'd like to use a transceiver I've used before, the MCP2562, and I suspect there's not likely ...
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389 views

Rx Buffer overflow in MCP2515 CAN controller

Here is my context: I connect to automobile drivetrain CAN bus (Volkswagen Passat) and sniffer all the traffic. The problem is that when MCP2515 got a message from CAN and I read it via SPI, the ...
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2answers
51 views

Can we connect a DAQ to a micro-controller via a CAN bus?

I want to establish communication between an Arduino to a DAQ that I am using from DEWESOFT called the Dewe 43-A. The DAQ has 2 CAN bus ports according to its specs, and I was wondering if I can ...
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429 views

Overloading of ESD protection diode on CAN lines through current during Bulk current injection - test

I have a design checklist question for a typical CAN circuit for an automotive application as below : The question is related to the ESD suppressor : "Was a capacitor parallel to the diode considered, ...
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202 views

CANopen SYNC object and synchronous window length

In CANopen specification there is an object called Communication Cycle Priod [1006h]. This is the time interval between two consecutive SYNC objects. There is also another object called Synchronous ...
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1answer
73 views

Change operational mode of CAN transceiver

I have two MCP2515 stand-alone CAN controllers with an SPI interface, two TJA1042 CAN transceivers, and two Arduino Uno boards. As you may know, TJA1042 has two operational modes: sleep mode normal ...
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187 views

How does the data rate of a CAN bus affect the value of the capacitor used in a split termination scheme?

I'm helping to redesign the CAN bus of an electric car, and we're interested in achieving higher data rates of up to 8 Mbit/s. We have a transceiver selected, a CMC to reduce inductively coupled ...
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1answer
321 views

Problem capturing specific signal from CAN bus

I am having a problem capturing a specific signal from a CAN bus. Since this task is quite out of my ordinary area of work it might be a pretty simple question. On the device reading from the CAN I ...
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762 views

STM32F407VG DISCOVERY BOARD micro controller CAN messages

I am wondering if anyone is familiar with any STM32f407VG micro-controllers? If so, I am having some problems configuring a CAN driver. I can run the demo code, which is set to a loop-back mode, but ...
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363 views

CAN Bus Debug MCP25625 CAN to SPI to USB (MCP2210)

I am trying to build a CAN - USB converter using the MCP 25625 chip to convert CAN to SPI first and then receive/send the SPI data on an MCP 2210 chip of SPI interface and consequently convert to USB. ...
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1answer
347 views

MCP25625 LoopBack Mode Reponse

If anyone has worked with the CAN MCP25625 chip in the past I would like to know if in the loop back mode if we load and send data on the TXB0 buffer are we supposed to receive a RXB0 buffer ready and ...
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398 views

Is it possible to flash an Atmel SAM E70 through a CAN bus without a JTAG?

My circuit board needs to have both a MCU and a CAN connection so it would be nice to be able to cut down on some of the components.
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CAN bus sensors

I want to replace a broken CAN bus sensor with a new one. How can I do it? I don't have node ID of the broken sensor. Is there a way I can find the node ID of previous sensor? It's an angle sensor (...
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1answer
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CAN Bus with RS485 CAN HAT for Raspberry PI

I have set up a CAN bus between 2 STM32 Nucleo's, where one is only sending messages and the other one is only reading them. This works, I have also validated this by connecting them to another CAN ...
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How to “clean” a DC brushed motor : noise on CANbus even without moving!

We have very odd problem with a DC brushed geared motor that we are driving with a classical H-bridge chopper (20kHz PWM at the moment). The motor kinda looks like a Mabuchi from an R/C car but with ...
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34 views

How to find the right components for the CAN bus signals merging?

I have 2 CAN connectors from 2 different devices and I want to design something that takes in both the inputs and gives the output on a single connector. In other words, I want to combine 2 different ...
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43 views

Use “basic CAN” if “full CAN” is available?

From all I've read about both types my conclusion is that the only reason for using "Basic CAN" is to make message handling easier: I have to care about only one buffer. One big drawback is ...
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62 views

Bus communication scheme for large number of devices (255+ nodes)?

I'm trying to figure out the feasibility of setting up some type of differential bus communication for up to 400 devices outdoors. The main constraints are mainly power consumption, complexity, wire ...
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Can-Bus blocked

I have a STM32F105 DevBoard which I implemented on it a simple code to receive frames from the can-bus The problem is on some can-bus lines it does receive the frames but on other lines when the can-...
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UDS vs XCP (Diagnostic)

When performing a calibration or a diagnosis acquisition from an ECU using a CAN-bus is there a protocol preferred? I've come across UDS and XCP but I can't quite get why one might be preferred over ...
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STM32 CAN Interrupt causes program to jump in infinite loop

Struggling with this issue for days now and can't find a solution. Maybe someone saw something like this before and can give me a hint. I have FreeRTOS running on an STM32L4 with different tasks. One ...
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Sharing Isolated Power supply for CAN and RS485

I am using ISO1432 from TI for isolated RS485 transceiver function. And ISO1042 for Isolated CAN transceiver. Both devices requires an isolated supply on bus side. Can I use one isolated 5V DC-DC ...
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1answer
52 views

Separate CAN messages having same ID in function of data content

I am working with some temperature and pressure sensors. These sensors send the messages to a receiver connected with Dewesoft Sirius. In this way I can read the CAN messages on my laptop. The problem ...
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1answer
53 views

RS485 over CAN: when and why?

I'm designing my own home automation gateway and I've already added a rs485 transceiver, everything is fine, but I'm thinking about adding also a CAN bus transceiver because I've seen that it's often ...
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1answer
61 views

2 devices with different CAN baud

I have a project where I need to talk with 2 devices x & y with 125kbps and 500kbps CAN speeds respectively. So I selected an MCU (F446RC) with 2 CAN controllers from ST. The BOM cost went up and ...
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Designing a universal CAN bus interface

I'm tasked to work for several car manufacturers and would like a system that can work with 'every' car. For example, I bought the peak system CAN Bus usb, and tried it for Kia e Niro and it didn't ...
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CAN Bus: Nodes powered by different Potential Sources

There was one similar question asked in 2018 but there was detail lacking. So here goes: I have an engine running J1919 CAN bus about 15m away from an Engine Info display that receives CAN-bus data. ...
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If Pointer Extension = 1, what should Pointer become then in J1939 standard - CAN bus

Assume that we have the EEPROM address 647 and we want to read to it. That can be done in J1939-21 CAN bus standard. But the problem I faceing is that if I'm using Pointer Extension = 1, then I can't ...
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What is “Number of occurrences” in DM16 - Binary data transfer at J1939 CAN-bus protocol

After I have send a DM14 memory access with the functionality read. Assume that I'm want to read 646 and 647 address. Then I want to use the lenght = 1, Pointer Type = 1(if I want DM15 message ...
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Which protocol specifies the meaning of each bit in a CAN message?

A lot of books and articles describe the basic idea of CAN (controller area network) and the requirements to the physical layer as well as the data link layer. But I didn't find any description how ...