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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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18 views

Connecting CAN transceivers for devwork /home prototyping

I'm doing some home project, and would like to use this CAN transceiver (note just in case, not selecting CAN controller+transceiver chip, that's how I need it). I would like to use this transceiver ...
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CAN Sniffing - is my approach flawed? [closed]

I'm working on an automotive project to sniff CAN data and reverse engineer PIDs. The project is based on a ChipKit Max32 & Network Shield - chosen for its dual channel CAN controllers. The idea ...
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I have a CAN transceiver circuit with the STM32L496 discovery board. How do i program the hardware to receive and transmit VEHICLE data? [closed]

The hardware of the circuit is similar to the draft below. Having trouble with programming to the vehicle.
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Teensy Canbus issue

I have two teensy3.2 with Canbus modules each with their own 12v power supplies, connected via twisted pair. Mod 1 has only a tact switch connected and Mod 2 has only an LED-resistor pair. What is ...
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CAN BUS and CAN Protocols

The Deutsche 9 pin(gree,type2) connector in heavy-duty vehicles outputs the following protocols. Connector pin C,D is used for J1939@500kbps, pin F,G is used for J1939@250kbps and H,J is used for CANH&...
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TVS protection for CAN bus

It looks like every chip manufacturer has their own CAN bus TVS product nowadays, e.g. ON Semi NUP2105, Semtech 2492SQ, Bourns T24CAN, Nex PESD2CAN and many others. What is common for all of them is ...
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44 views

Safe and feasible way to multiplex CAN bus?

Is there a standard method or tool to connect more than one CAN bus to a CAN controller with single CAN interface? Each CAN bus would be directly connected to individual transceivers and then the Tx,...
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38 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
95 views

Can I use this analog switch for CAN bus signals?

In the deutsch 9 pin obd interface for heavy trucks, some manufacturers use the pin F,G for J1939 protocol and some use it for J1708 protocol. I am trying to use a NLAS4684 analog switch with dual ...
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31 views

STM3F405RG CAN bus issue

I encountered stange behavior of stm32f405rg while working with CAN. My setup: beaglbone black connected to stm over CAN bus. Data transmitted successfully, beaglbone is able to receive data correctly ...
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3answers
78 views

CAN BUS electrical characteristics

I know that CAN bus has two states. Dominant states where CANH goes 3.5V and CANL goes to 1.5V and in recessive state, both CANH and CANL goes to 2.5V. My question is, how much current does it draw in ...
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47 views

I am trying to make a OBD logger for heavy-duty vehicles

The thing is that I have to use one CAN transceiver and one CAN controller. Both have one interface (CANH and CANL). I use dip switches to route different CAN signals whenever I need to using a DIP ...
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2answers
77 views

Can we implement physical DIP switches to route different differential signals?

I want to route two different CAN BUS signals (differential) to a CAN controller. Since the controller has only one CAN interface, I can not connect both differential CAN signals to the input of the ...
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2answers
77 views

Should I remove the termination resistor from the CAN Bus transceiver module?

I develop a CAN-BUS receiver (logger) with an ESP32 and CAN-BUS transceiver. The CAN-BUS transceiver modules which I found and bought have both 120 Ohm termination resistors. But the CAN-BUS to which ...
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1answer
40 views

How to determine the length of the last data field in a SDO block transfer?

I've got a problem with the implementation of the CANopen SDO Block Transfer. The transmission is ok except the last block: ...
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2answers
82 views

Need a solution to sent i2c data long distance (prefereably convert to CAN)

Is there any IC available that can read I2C data from a sensor and convert to CAN. I was looking for a low-cost solution to reading i2c data and putting it on a CAN bus. Reading i2c with a ...
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54 views

HAL Library CAN Bus interrupt sources and callback functions

Im using STM32F407 Discovery board and HAL library in CAN bus(CAN1) Some receive interrupts used with callbacks (for example receive interrupt...
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67 views

PCB Routing of CANH and CANL

Continuation from an earlier question: Current Consumption of CANbus (CANH and CANL) I understand how to specify my power supply for multiple CAN transceivers but I am now wondering about the details ...
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1answer
55 views

Current Consumption of CANbus (CANH and CANL)

I'm looking to use the SN65HVD230 CAN transceiver but had a question about the current consumption. Datasheet: http://www.ti.com/lit/ds/symlink/sn65hvd230.pdf In table 8.3 Recommended Operating ...
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72 views

CAN Bus Frame Error [closed]

3.3 CAN Controller. Recessive state 1.85V...Talking to third party 5V CAN. Recessive state 2.4V. Both have dominant differentials of >= 2V. Two 120 ohm resistors on bus, 63 ohm resistance throughout. ...
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1answer
59 views

Questions about CAN

I'm trying to build a network of interactive LED matrices which will communicate to each other. Each node will be a circular PCB containing an 8x8 RGB LED matrix that is connected through a vertical ...
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1answer
90 views

Can RS485 be considered a multi-master bus?

There are some electrical specifications specifically designed for multi-master protocols such as CAN, I2C, 1-Wire, etc. which are classified under CSMA/CD networks. However, RS485 has a push pull ...
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47 views

CANopen addressing scheme?

TL:DR Using CANopen, don't see CANopen IDs on the bus. I'm very confused. I have a semi-functional CANopen network set up between a PLC and a motor controller. Those two items are the only two nodes ...
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65 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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2answers
42 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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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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108 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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2answers
64 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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108 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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52 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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56 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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2answers
78 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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55 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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50 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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2answers
76 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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26 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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48 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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63 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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42 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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47 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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19 views

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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47 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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126 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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1answer
39 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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27 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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51 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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152 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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1answer
48 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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1k views

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 ...