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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55 views

Selecting wiring hardware for CAN network

I'm having trouble selecting wire, jack and plug for small (up to 6 nodes, 3-4 m) CAN network. Each node will have 2 jacks wired for pass-through and short patch cables will be used to daisy-chain ...
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127 views

IoT vehicle monitoring interface

Creating an IoT vehicle monitoring interface using the Arduino CAN-bus shield and the STM32L496 discovery kit to transfer the received data to cloud. What pins should be physically wired between the 2 ...
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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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Why does CCP require CRO/CRM messages to be 8 bytes?

In the CCP (CAN Calibration Protocol) V2.1 standard it is stated that CRO and CRM message objects must have a DLC of 8 even if they aren't used. What is the purpose for requiring these message objects ...
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100 views

CAN Physical Layer With Different Characteristic Impedance

The company I have been working for, which is designing a new control system for forestry equipment, has encountered a number of problems with regards to the CAN bus it is using for communication. I ...
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54 views

CAN Transceiver Current Draw

I'm trying to determine the input current required to operate the following SN65HVD233 CAN transceiver at 1Mbaud: http://www.ti.com/lit/ds/symlink/sn65hvd233.pdf The first spec I see listed is ...
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103 views

High Speed PCB routing [closed]

I'm a new hardware design engineer. I have a few questions about high speed pcb design. 1) when I search high speed pcb design, I saw pcb routing like snake. What is this ? 2) When I draw a high ...
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39 views

MCP2515 wake up CAN device

I am using a CAN Bus shield for a raspberry pi which uses MCP2515. I want to wakeup the connected CAN device, send a message, and put it back to sleep. I am aware there is a sleep mode on CAN ...
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46 views

CAN bus load limitations

I have to send periodic frames with high frequency on a CAN bus. When I do that, the bus load becomes more than 60%, which causes delay with the received frames. Is there a problem when using higher ...
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69 views

CAN bus TX failing in a strange way

I have been trying to pass CAN frames between two different CAN busses using two different CAN channels on a STM32F746 MCU. The system always fails and freezes up in TX when it is supposed to be ...
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42 views

high-speed vs. low-speed CAN

I'm working on some CAN-topics and asking myself what are the differences between high-speed (ISO11898-2) and low-speed CAN (ISO11898-3). I spent some time for searching informations and found the ...
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45 views

Do I need to measure impedance before every CAN termination?

Background: I need to set up a CAN bus between different components of an electric UAV (battery management system, motor inverter, autopilot, etc.). My avionics/networking experience up to now ...
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67 views

Isolated CAN transceivers as a CAN bus extender

I am designing a system to 'hack' into a CAN bus. My first idea was to split the target CAN bus, terminating both ends into isolated CAN transceivers, and use a MCU to pass packets between the buses ...
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23 views

CAN Transciever kbps to Hz at TXD Pin

I am new to the CAN Bus and have designed an application example. The Transceiver I have chosen is TJA1044Gx. The transceiver data sheet says : I want to know if I have only Transceiver, Analog ...
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41 views

CAN Problems with MCP2515, MCP2561 and Rpi

I work with some devices which used STM32 MCU and MCP2561. Theses devices talks on a CAN Bus. Everything is ok. But when i plug a Raspberry Pi with a MCP2515(Spi) and a MCP2561. I see a lot of ...
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48 views

CAN Rx Line between STM32 and MCP2561

I discover a problem on my design, with a STM32F042K6 MCU and a MCP2561 Can Transceiver. I can send some frames on the CAN Bus but i can't receive any frames. When i put my scope probe on the CAN Rx ...
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32 views

CAN transceiver Vref connection

I am using the TI SN65HVD230DR CAN transceiver on two separate CAN buses between three microcontrollers (MCUs) -- two are on the same board, and one is off-board. This transceiver includes a Vref pin:...
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45 views

CRC in CAN Messages

I would like to know the difference between CRC calculation in CAN physical layer vs CRC calculation in the application layer. How does the CRC calculation in these layers affect the ASIL (Automobile ...
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CAN Bus Isolated Ground Trace Layout

I'm using an ADM3053 isolated CAN transceiver in my design, which, due to layout constraints, is located ~6" away from the board CAN connector. The CAN_H and CAN_L traces are routed as a 100Ohm ...
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38 views

Low-Speed CANbus Common-Mode Choke Insertion Loss

I'm designing a low-speed CAN transceiver breakout-board (schematic below) and I'm trying to select the proper choke to use to reduce common-mode noise. I've found a few common-mode chokes meant ...
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123 views

Detect if a CAN node is transmitting or receiving

I am not an electrical engineer or EE student; I'm a diagnostic technician. AFAIK, a CAN transceiver receives bits by measuring voltage between the network and its ground/low reference (high ...
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33 views

MCP2561/2562 CANbus voltage?

The datasheet says the MCP2561/MCP2562 is suitable for 12V and 24V systems except that everywhere I look in the datasheet it says VDD needs to be between 4.5 to 5V. How can CANH be greater than VDD or ...
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26 views

Playback log files in can bus

I'm using MCP2515 CAN Bus controller and I'm connecting between two boards successfully. I have bough a can bus analyzer Ksaver, which allows to playback log files. I connect the logic analyzer DB9 ...
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46 views

ESD Diode - clamping voltage

I'm trying to replace an existing ESD diode(PESD1CAN) in my application CAN circuitry due to some reasons, I've found an alternative ESD diode(RSB27C2), but compared to the diode that I already have ...
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101 views

CAN BUS ON ATTINY85

I have some difficulty migrating the MCP_CAN_lib-master library to work with tinySPI the goal is to setup the ATtiny85 so that it can read all the can messages on my system currently there are three ...
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45 views

Type of terminal/connector to use for CAN bus on Arduino MKR CAN Shield

Probably, this is obvious to everyone, but since I am a newbie to electrical engineering I am stuck. I have two wires of a CAN bus, (CANL and CANH), and I wish to connect them to the Arduino MKR CAN ...
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What is the limiting factor for a CAN bus to exceed 1Mbps bandwidth?

Why can't CAN baud rate increase beyond 1Mbps
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CAN bus bit timing STM32F7 (bxCAN)

I am struggling with a bit timing of CAN bus. Perhaps, someone will be able to explain me, how it actually works. There are two configurations of the CAN controller inside STM32 (bxCAN). The desired ...
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1answer
126 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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45 views

I/O expanders- CAN & I2C

Currently in my system we use 16 I/O expanders with I2C interface. I want to change it to CAN interface. Which is the best possible way without compromising the cost? I tried searching for 16I/O ...
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65 views

Communication via I2C sensor via CAN bus

I am wondering if it is possible to implement the following idea: I want to build a network of sensors, all of them communicate via I2C protocol and all those sensors will send their parameters via ...
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168 views

STM32F429 CANopen with or without transceiver

this might be a stupid question but i'm unable to clarify this by myself. So i'm working on a project with a STM32F429zit microcontroller. I would like to use CANopen in my project so i can ...
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63 views

Bulk Current Injection on CAN bus

I'm trying to understand how the Bulk current injection would look like on the CANH and CANL lines, to understand the overloading of the ESD protection diode on the CAN lines and capacitors in ...
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107 views

Bulk current injection - Resonant frequency of ESD protection diode CAN bus

Link to the application note that I'm referring to below. I was going through an application note by On Semi, System Level Surge Suppression Solutions for the CAN Bus -AND8253/D, where it says that ...
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136 views

CAN bus with star configuration/long stubs

I am assisting in the development of a machine, and have been tasked with achieving high speed CAN (as close to 1 Mbit/s as possible) in a star configuration. The restrictions are: each arm is ...
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1answer
46 views

How would I place CAN termination resistors in a 3 ended configuration?

I have a project for which I have one central circuit board which has a can node on it, this central circuit board has three connectors on each of which a node could or could not be plugged in with a ...
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59 views

Recommendation for series protection resistors on CAN bus?

When implementing an RS-485 interface, I tend to follow TI's recommendation in the SN65HVD75 datasheet to include \$10 \Omega\$ series resistors on the A and B lines. The TVS diodes I'm using clamp ...
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52 views

Should I take precautions when using different CAN transceivers on the same bus?

What are the precautions I should be aware of when using different transceivers on a CAN bus? What I can think of: They neeed to operate at the same voltage (on ...
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203 views

Is it common practice to connect power supply to a DB9?

I got a project where many sensors which uses CAN were connected to a DB9. And sensor power (24V and GND) too. I want to connect the DB9 terminal to power however how can I do it in a safe way? If I ...
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2answers
178 views

STM32 CAN bus Rx interrupt only triggers in loopback mode

I'm designing the CAN interface for a STM32F042C4T6 to be able to receive and send messages. I've tested my code and everything seems to work perfectly fine in loopback mode. However, when I hook up ...
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Why High Speed CAN messages with a recessive level in ACK slot from OBD II port on 2019 GM Chevy Cruze

I want to collect some CAN traffic from my car. I got two devices. One is Saleae Logic8. The other is Vector VN1630A. I think the CAN protocol is straightforward that we can listen the CAN traffic by ...
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Microchip documentation does not label CAN buss pins on micro controller pinout diagram

Link to the data sheet I want to use Microchips DSPIC33FJ128GP802 in a new project and want to use the ECAN buss. The problem ...
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137 views

STM32F0 CAN Transmit Timeout

I'm new to CAN communication and trying to setup CAN (normal mode) between two identical custom boards having STM32F072 controllers. Code generated using CubeMX (STM32Cube_FW_F0_V1.9.0) drivers. Here ...
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173 views

Does CANbus need to be isolated?

In my design - rugged computer - I have connected the digital gnd to the isolated CANbus gnd by mistake. Does the CANbus standard state that it has to be isolated? Can that connection harm the CANbus?...
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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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50 views

J1939 Wiring Considerations [closed]

I am new to the forum and hope you could put me in the right direction. When designing a J1939 harness what is the physical layer constraints, if multiple ECU's need to be connected? Is there any ...
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112 views

Optimum number of CANopen nodes in a CAN bus for motor control

I am studying about the CANopen implementation in a motion control work. CANopen is a protocol over tha CANbus. It is seen that, in the CANopen specification, theoretically at most 127 nodes could be ...
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How to calculate bus load of CAN bus?

I have a few questions regarding CAN bus load Is there any derived equation/formula to calculate the bus load? I need transmit below frames(Assume Standard frame format) at baud rate 500 kbps on the ...
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89 views

Medium Range Two Wire Bus Recommendations?

Do you have any recommendations for a medium range (~10 meters) two-wire bus? My supply voltage is 24V and I'll have a single master with ~50 slaves connected to it. I've looked into: I2C - Great but ...
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78 views

How to select the most appropriate (serial) bus for controller?

In the context of a robotic project where different 'payloads' and/or robotics arms (end-deflector) should be mated mechanically with power, data and control connections support, I would like to ...