Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

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CANOpen SDO block transfer retry if timeouted?

I'm using the CanFestival CANOpen library (https://canfestival.org/) for a PC app that talks to a device via CAN bus. The device is CIA-301 compliant. I'm using SDO block transfers for device firmware ...
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Topology and protocol for boards connection

Would like to have some insight on which data protocol to use to communicate between a master and several slave boards on a project i'm working on. My initial idea was to daisy chain all the slaves. ...
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Serial Camera Control Bus (SCCB) - Why are my Serial Input Output Data line always high?

I'm looking for a SCCB library for the camera OV7670 and I have been looking everywere for C code that fits OV7670. But the problem is that my SIO_D (Data line) is always 1 when I read the data line. ...
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Sliding window protocol

In the sliding window protocol when the receiver sends RRn to the sender the receiver's window is shifted to the right now starting at the n position correct? Suppose this is the window of the ...
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Identification - 3-pin 3.3V serial port?

I'm trying to identify this port and read data off it. It's 1cm across, including a small square on the lower left. 3 pins, leftmost near square seems to be GND and rightmost reads 3.3V+ w. respect ...
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Reading data off a watt-meter comm. port

I have a no-brand Watt meter with an unlabelled 3-pin port at the side, presumably for reading the data off it. Pic: https://imgur.com/a/IuxEUh3 Ebay listing: https://www.ebay.com/itm/154741876757 ...
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Issue with serial interface of Futaba LCD M162MD07aa-000

I have purchased a Futaba LCD from Mouser, https://www.mouser.com/ProductDetail/Futaba/M162MD07AA-000?qs=PzGy0jfpSMv5CfcVuWSnKw%3D%3D It says in the datasheet that it supports three modes; I want to ...
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read multiple digital sensors over protocol

I have 200 digital sensors that I need to read its state from a arduino. What I was thinking about is to make something like digital leds, where i connect 200 IC's in series. the first IC gets a "...
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Identifying a communication protocol found on a RJ14 cable

I have a LED panel controller that can daisy chain with an another led panel controllers using a RJ14 cable to adjust a PWM that dims the panel. This is what I see on the RJ14 pins. A periodic signal ...
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Why do we need FPGA and not microcontroller to implement Bitbus protocol?

I need to design a board with a Bitbus protocol master to interface with other slave devices and was searching for options. All I get is Bitbus protocol IP for FPGAs. Why can't we implement Bitbus ...
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How does USB C PD to DC power negotiation work

I have a battery and would like it to output power from its USBC PD to a DC input device. The device has a fixed resistance and the device must receive 20V fixed. How can I do this?
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Does the SPI protocol specify how many clock pulses a master device should send to the slave?

I'm trying to implement an SPI device in Verilog. I'm having a lot of problems for coordinating master and slave, since sometimes (with my current impl.) the SPI master device doesn't send enough ...
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Rs485 A & B Labels being used inconsistently

I would like to know if there is an official standard with regards to rs-485 terminals being labelled A & B. I have always believed: A=> + (positive) and B=> - (negative) however, I have ...
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Figuring out communication protocol

Complete beginner trying to learn by doing here... Background: I have a wine cooler (for beer) that I want to remote control the lights on by adding a microcontroller. I'm planning on using a ESP32 ...
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What is the interface type of this LCD?

I'm trying to find out if this LCD uses eDP, or MIPI DSI, or something else so that I can choose a replacement LCD, and I'm a beginner at this. I wasn't able to find it on the manufacturer's website, ...
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Why does SAE J1939 Commanded Address requires a delay when sending multiple package message?

I wonder why the command Commanded Address from SAE J1939-21 protocol, requries a delay between 50-200ms for every multiple package message for the transmitter. Why? Does the microcontroller unit not ...
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Do all flash memory chips pinout layout and usage follow a specific standar(s) and protocols?

As I see in this question I see that WINDBOND W25Q128FV has similar pin inteface/layout with the Maxronix MX35LF1GE4AB. Therefore, the following question came to my mind, do all flash memory chip ...
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SPI modes of data transfer

I am learning SPI protocol in serial communications now. I got stuck with the clock phase and polarity controls concept. Why there are 4 modes available other than a single universal transfer mode. ...
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Help to identify CAN packets of a lift-fork

I have monitored the CAN bus of a lift-fork but I can't recognize the meaning of the packets that was being sent periodically on the bus. Do somebody have an idea on how to interpret these packets ...
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1 answer
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CAN Bus Hardware Design with 1000 nodes

I am looking to develop a CAN Bus System employing up to 1000 nodes on a single network. I am using an existing design based on STM32F072CB that has the CAN Controller embedded along with TJA1050 as ...
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What is the difference between AR/AW/ACSNOOP in AXI & ACE?

I'm exploring AXI and ACE protocols and I found 3 different appearances of a SNOOP signal: ARSNOOP AWSNOOP ACSNOOP I can't get the purpose of the 3 different lines with the same(?) signal. At least ...
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Shownig RTNETLINK answers: Operation not supported while setting CAN bus modes

I'm new to CAN bus and I'm trying to write some data frame on CAN bus from a CAN node to another CAN node. I have enabled CAN device driver through my build source. But whenever I try to select mode ...
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J1939 - Source Address field and Address Claim for a diagnostic/scanner board

I have a board that include CAN hardware, I would like to use it to scan some PGNs of the J1939 protocol on a fork-lift. This is the packet: Below we have the the PGN 65262. Considering that all the ...
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ASi (AS-Interface), understanding Power Supply

Can somebody help me understand the ASi (AS-Interface) power supply. I think I understand how the data decoupling works (because of the induction voltage of the inductor). But I dont understand the ...
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What is the meaning of pulling a pin HIGH (of an IC)?

Let's say I have a microcontroller (ESP8266) driving a DAC via a I2S protocol. So the ESP is connected with 3 pins to the DAC, and sending the data to it throught these pins. But I wonder, how exactly ...
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BLE emission when disconnected and waiting connection

I'm working on a toy device that goes into an airplane. It is using a BLE device and yet my knowledge about is a quite limited. If I understood correctly, usually in protocols: the device advertise, ...
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CHADeMO protocol understanding

I want to know specification for CHADeMO standard,its a fast charging method for electric vehicle upto 400 kW preparing 900 kW on the map.I tried searching data for CHADeMO but just found above ...
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How should I interpret this CAN bus protocol - J1939

I have been using J1939-21(Data link layer) many times, but now I'm confused. First I know that a J1939 protocol is build up from a data frame and that data frame looks like this in practice. ...
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Figuring out transmission protocol in cheap wireless door bell

Due to boredom I've tried some reverse engineering of simple cheap wireless ring bell which uses 433.92MHz transmitter and receiver via OOK modulation. It sends several times the same information. On ...
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Teraterm to show hex data [closed]

I am getting UART data from micro-controller to PC. Micro-controller sends data in hex(eg.0x1B) format which can range from 0x00 to 0xFF. I want teraterm to display the received data in hex format. Is ...
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spy/monitor and decode spi protocol between master and slave

I often find my self in a situation when i need to debug systems of a MCU and other device which comunicate by SPI interface. most of the times we use a logic analyzer between the master and the slave ...
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Still confused about SPI implementation FIFO to buffer

Point 2 of page 16 in this document (image shown below) states that: The contents of SPIxTXB are moved to the shift register SPIxSR Exactly how is it moved, is it moved serially or in parallel? I ...
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Serial communication protocols used in spacecrafts and airplanes

I always see that CAN bus is used in automobiles for communication between nodes and for on board diagnostics and basically for the overall functioning of vehicle. What are the similar serial ...
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2 votes
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Logic analyser reads bits as if they are shifted left by 1 bit, what could be the issue?

The logic analyser is from Hobby Electronics, and is being run on the PulseView software. It is not reading the data correctly. All of the bits are shifted one to the left so everything is read ...
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Communication protocol analysis via microcontroller board

I have an idea for my master's thesis. I want to make a communication protocol analyzer and monitor the data on a PC via software I coded. For the first stage, I need a kind of data acquisition system ...
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-2 votes
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What are the modern uses of SPI and I2C protocols [closed]

I have been using I2C and SPi for a few years now, but as I begin working with USB, I realize it is much faster. I still see devices with 2 MCUs that could potentially communicate faster with USB, but ...
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3 votes
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Why does bluetooth (still) only support pairing two devices?

When bluetooth was first devised there was typically only one device to connect to at a time so it was quite natural to just implement a pairing protocol. I believe we are now on Bluetooth 5 Why is it ...
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Which differential protocol to use when redriving Ethernet?

I want to redrive a 100-BaseTX signal on a board. The signal is to be redriven 3 times (by the same setup). On one end is a STM32 NUCLEO-F767ZI board, and on the other end is a GbE switch including ...
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"smart" label on home gadgets package and mcu [closed]

Are any home gadget that is written "smart" on the packaging, capable to interact with a microcontroller through some protocol or "smart" label is just another marketing ploy?
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How to find and decode a particular protocol

I'm trying to understand what protocol is used on a particular device in order to decode it and send custom values. So far I was able to record the data with a logic analyzer but couldn't figure out ...
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RS485 communication issue

I have used PIC18F45k40 device for RS485 communication. I have 2 ckts one is isolated and another non isolated RS485 design. I have schematic & placement for reference. I have connected multiple ...
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Address-free communications between microcontrollers in any topology

Suppose I have 9 microcontrollers each on their own PCB, connected in a square grid. Is there a way I can get a single node to communicate to all the other nodes, be able to address them individually, ...
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Frequency Key Shift technique to superpose the digital communication on top of 4–20 mA signals

I start working with HART devices and I really try to understand how digital data is transferred trough 4-20 mA current loop. I start read this article: https://instrumentationtools.com/hart-...
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What are examples of complex communication protocols that do not need a 7 layer OSI model to describe them? [closed]

I am trying to dissect an existing design of a custom communication protocol that shall make use of infrared pulses to communicate between only 2 devices. The design is architected in such a way that ...
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SPI Slave implementation in software

I need to implement SPI Slave (@10Mhz clock) on a microcontroller (a sensor with Cortex M33 core) in software. The problem is software is not fast enough to prepare data just after the command. (also ...
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4 votes
6 answers
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Logic analyser or oscilloscope? [closed]

I am an embedded enthusiast and very much into embedded C and firmware development. I love to interface different sensors and modules to MCU by creating my own libraries from scratch. Now for ...
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What is "Pointer" in DM14 at J1939 CAN-bus standard?

What is "Pointer" in DM14 at J1939 CAN-bus standard? Can it be the memory Address[DEC]?
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Help using usb c to power display

Here is a bad diagram of a project I’m working on. In a beginner to EE and this stuff. I have a laptop display connected to a controller board I got on eBay. It has a input of hdmi and a dc power jack ...
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1 vote
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Splitting pins on USB-C

I’m new to EE and I have a project I’m working on that has confused me. I have an old display from a laptop that I want to make into a custom 2nd monitor, I bought a driver board for that model ...
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J1939 - CAN BUS - What is ECU and ACU?

I have a question about the CAN-bus protocol J1939. What is ECU and ACU? Assume that we have three motors that can be controller via J1939. Each motor have it's source address 0x80, 0x81 and 0x83 and ...
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