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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Why does the CAN bus use a 120 ohm resistor as the terminating resistor and not any other value?
I know the reasons for using terminating resistors on a CAN bus and how important it is.
But why 120 ohm? How did this value come up? Is there any specific reason to use 120 ohm?
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Is a CAN enabled microcontroller sufficient to drive a CAN bus?
There are a number of CAN modules built into microcontrollers these days. The PIC18F2480 is an example of that. Is that microcontroller (with built-in CAN) capable of driving a CAN bus on its own or ...
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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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Is a ground/common needed for proper CAN bus communication?
Since CAN Bus is a differential signalling system, what is the significance of GND/COM signal? Can I get by without it?
I've got a very simple 2-node system that has some weird happenings going on. (...
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CAN Transmission and termination resistors
I have been trying to set up a CAN network using PIC18F25K80 microcontrollers and an MCP2551 to communicate between them. Can I use two simple wires as a CAN bus by just connecting the CANL, CANH of ...
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STM32 HAL_CAN_Transmit always returns TIMEOUT (HAL_CAN_STATE_TIMEOUT)
Setup
I am using an STM32F103C8T6 (aka Blue Pill).
With the STM32Cube I set CAN_RX to PB8 and CAN_TX9 to PB9 (these are defaults/nonchangeable).
Circuit
simulate this circuit – Schematic ...
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Implementing a CAN protocol layer in software
Background
I'm developing a project which will require the modest microcontroller specs of:
8 12-bit, 10kHz ADCs
1kB of RAM
48-QFN or smaller footprint
20kbps daisy-chainable noise-resistant and ...
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CAN bus layout design
I am trying to design a CAN bus node. The CAN bus shall be split-terminated with 120Ohm, 60Ohm for each line.
Therefore i tried using this paper to calculate a characteristic impedance of 60Ohm for a ...
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Controller Area Network (CAN), high speed and low speed
Is the difference between high- and low-speed CAN only with respect to baud rate values?
Is the CAN transceiver programmable for a range of speeds or is it fixed for a specific value? For example, can ...
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CAN bus goes through periods of re-sending messages continually
I'm having an issue where my microprocessor CAN bus module continuously re-sends its last message, even though it seems to be received properly by my USB-CAN monitor on the other end.
I'm attempting ...
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Difference between buffer and mailbox
Peripherals in Micro-controllers usually provide a way for us to send and receive data from it. Usually this are memory mapped registers.
I have come across few terminologies. The most often used one ...
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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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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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Same priority for masters in a CAN network
I'm aware that messages on the CAN network are assigned priorities. I'm working on a 2oo3 voting system, and if each of the messages by the three masters are given three unique id's, I'll be making ...
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What's the maximum CAN bus frame (message) rate at 125 kbit/s?
My CAN bus is running at 125 kbit/s and is using extended frame format exclusively. I would like to know what's the maximum rate of CAN frame I can send out. Suppose the data length is always ...
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