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Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

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38 views

Mbus Optical readout of energy meter?

I have a Sharky 775 energy meter, that I would like to read data from periodically, either using an Arduino/ESP8266/ESP32 or a Raspberry Pi and gather/display data via MQTT. The datasheet and ...
2
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1answer
32 views

What happens when there is a simultaneous Read and Write launched to the same address in AXI3/4?

I have a doubt regarding the AXI3/4 protocol. Assume a hypothetical scenario where a single master issues a valid Read and Write transaction to the same address simultaneously. From the AXI ...
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0answers
13 views

Average and maximal number of time slots in adaptive tree walk protocol

I was wondering if it is possible to know the maximal and average number of time slots that will pass until and including the time slot in which there will be a successful broadcast, knowing that two ...
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0answers
10 views

finding the minimal length of a broadcasting frame in a channel(CSMA/CD)

i am unsure about this question. would appreciate your assistance with it. in the following CSMA/CD network with cable length L and propagation T. assuming that the signal is not decreasing and there'...
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1answer
53 views

Bit-Map vs ALOHA protocol

So i have been reading about ALOHA and Bit-Map protocols and i am note sure which is more preferable in the following scenario: 8 stations, numbered 0-7 want to transmit in any given time slot. ...
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5answers
3k views

How fail-safe is \n\r as stop bytes?

In my UART communication I need to know the start byte and the stop byte of the message sent. The start byte is easy but the stop byte, not so much. I have implemented two stop bytes at the end of my ...
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0answers
20 views

calculating the probability of a successful broadcast in p-csma protocol

am quite unsure with the following question. would appreciate your help with it: in a 3 stationed p-csma network, where \$p=0.3\$, we know that in \$t_0\$ the network is restarted, the channel is ...
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1answer
110 views

How to monitor one wire “kind of” protocol

In the current network, there's 1 master device, which gathers data from over 20 devices. Nameplate says the baud rate is 2400. In the bus cable there's one data wire, 12V and GND. A friend of mine ...
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1answer
45 views

Why always in communication protocols R/W configuration,Reading is configured by “1” and writing by “0”? [closed]

when a microcontroller communicates with another one via one of the communication protocols there is a configuration bit in a control register to choose whether to send(write) or receive(read) this ...
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1answer
38 views

Do I have to initialize Dali lamp somehow if I use broadcast commands?

I have few Dali lamps. Some of them are new, some of them are used. It is hard to tell which was initialized (addressed?) and which was not. I have simple DALI circuit with microcontroller and simple ...
2
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1answer
49 views

MQTT Broker vs Server

I am trying to learn MQTT technology. What I understand so far, is that MQTT is based on a 'Broker' that does the 'Publish and Subscribe' of messages and topics. I wonder if it's another name for '...
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4answers
66 views

Video Protocol Without Required Speed

I am trying to output a video signal with a slow microcontroller (Arduino). I don't need anything fancy like HD or 30fps, and if it takes a second to update the frame that is fine. I was looking for ...
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1answer
74 views

Problem with SPI wiring?

Searching for images of SPI wiring between Master and Slaves, I found that some of them connect MOSI/SDI of master to MOSI/SDI of slaves and so MISO/SDO of master with MISO/SDO of slaves, meanwhile ...
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1answer
60 views

Using UART chip without programming control registers

Is it possible to use a UART chip without programming control registers? In other words, with Factory Default configuration? If yes, which ones? UART - SPI mode. I have examined the datasheet for ...
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0answers
64 views

UDS message (OBD related)

I write this question to try to understand how these automotive standards interface in the 7 level of the OSI Model. If my vehicle implements both, then in level 7 of the communication, each message (...
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1answer
156 views

Identify this open collector serial protcol

I'm trying to analyze the serial link between two devices, respectively a motor controller board and a Li-Po battery manager, which battery powers both devices. The application is a battery-powered ...
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2answers
3k views

How do universal IR remote “codes” work?

It is easy to find this kind of reference when searching for IR protocols and codes for specific equipment. The actual IR transmission contains far more data than these small codes can hold. What ...
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2answers
329 views

How does this fire alarm system transmit data on two-wire?

In the fire detection industry, analogue addressable systems use control panels and detectors (and devices such as interfaces) which communicate with each other by means of a protocol. What protocol ...
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1answer
70 views

Schneider Micom P123 trigger Output Relay

I am testing a Micom P123 relay with IEC103 protocol. I was able to communicate with 3rd party free Protocol Analyzer, Vinci. I was able to get Digital Input status. So communications is working good. ...
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0answers
38 views

Addressable RS485

I have a requirement to take a board that interfaced with RS232 and put it on a half duplex RS485 bus. The obvious problem is that at the very least the board firmware will need to be altered to be ...
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0answers
62 views

Offset QPSK Frame sync markers

What actual protocols exist out there that employ Offset Quadrature Phase-Shift Keying (OQPSK)? What do they use for the frame synchronization marker (or "preamble" or "sync word" or "flag")? Do ...
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2answers
828 views

Why are length-prefixed fields considered hardware unfriendly?

One criticism of GENEVE (a network encapsulation protocol) is that it uses tag-length-value fields, and these are hard to process in hardware. Why is this considered hardware-unfriendly? What ...
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5answers
2k views

UART- a protocol or hardware? [closed]

Some say UART is hardware, some say UART is one of the serial communication protocol. UART is a protocol UART is a protocol UART is Hardware UART is Hardware
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2answers
75 views

What communication method shouild I use [closed]

So I wan to control a bunch of devices. I though first of using RS485 but after some digging I figured out this might not work as I don't really have a pure daisy chain. The configuration I would like ...
15
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1answer
2k views

Official GPS protocol documentation?

Searching for "GPS protocol" reveals many sources for processed GPS data, e.g. NMEA or binary outputs of GPS units. Where is the official documentation for the GPS satellite - receiver protocol? Or ...
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2answers
492 views

The use of redundant I2C in spacecraft avionics

I recently read this report about the JPL x2000 avionics development project, which developed more modular avionics platform using commercial silicon, to cut cost and power. They opted for an ...
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0answers
14 views

Is there a stated tolerance on IRIG-B pulse lengths?

I've been looking at IRIG-B lately, and while I see that the expected pulse lengths are 2 ms, 5 ms, and 8 ms, I haven't seen specification of how much these pulse lengths are allowed to differ from ...
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2answers
1k views

What is difference between USB and TTL? [closed]

I have one question about USB and TTL. Both USB and TTL works on the same voltage range (0 to +5 V), both are serial protocols. From my point of view, they are the same. Why then we have USB to TTL ...
2
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1answer
155 views

How to prevent polling using RS485

I was advised to use RS485 since I have about 7 devices needing to talk to each other (and cannot get CAN to work). Although I want to start simple (two devices where one sends and other receives), ...
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1answer
66 views

How does Apple's ADB's collision resolution work?

I've read several different documentation sources explaining how Apple's asynchronous ADB protocol works. Although quite convoluted, it makes some sense of several rereads. I am having difficulty ...
1
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1answer
46 views

Serial protocol and connector choice for tethered firmware distribution project

I am designing a system in which a central host controller that has a cellular internet connection is going to be used to query/control/flash intermittently tethered (wired) nodes. The central host ...
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2answers
129 views

SENT protocol output unit is LSB. What does this mean?

I have read couple of datasheet of devices which uses SENT protocol. They define the output between 193 and 3896. The unit is LSB. I think that this does not mean least significant bit? Example: ...
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0answers
77 views

Identify TI motor driver IC (from old HP printer) or its control protocol

For fun, and as an exercise in reverse engineering junk hardware, I am trying to understand the internals of an HP DeskJet 840c printer from 2001. Specifically I am trying to understand how the motor ...
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1answer
72 views

Soil moisture sensor interface protocol

I want to get some measurements from a soil using a simple soil moisture sensor like this one: It has an analog output proportional to soil moisture. The goal is to send the measurements through Sub-...
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0answers
157 views

Is this UART communication encoded? How can i receive->decode and transmit->encode this data?

I get an unkown string when activating an UART-communication protocol of two devices I can't name here. That string is different everytime the devices are pared. The communication protocol acts as ...
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1answer
184 views

What kind of communication protocol is this?

I'm trying to reverse engineer the communication between two modules, a master and a slave, but I couldn't figure out the used protocol. All of the signs use 5V. The blue sign's frequency is 400 kHz. ...
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2answers
132 views

Difference between LVDS and “Low Power LVDS”

It sounds like a double emphasis but indeed, pin 25 of the LTC2323 (http://www.linear.com/product/LTC2323-16) I lets me choose between: CMOS (GND) LVDS (IOVDD) Low-Power LVDS (leave floating) As ...
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2answers
150 views

What is the specification need to be followed for SPI

I dont think we have a standard specification for for SPI unlike CAN and LIN. After Googling it found that motorola SPI and TI SPI are more commonly used but not able to find the referance documents ...
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2answers
130 views

How can I drive this LCD? [closed]

I have had this LCD lying on my shelf for the past few years and have not been able to figure out how to use it. It is an LCD from the printer Epson TX710W. I searched for a datasheet, but I couldn't ...
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1answer
62 views

USB IN endpoint

On reading about usb protocol in http://www.beyondlogic.org/usbnutshell/usb4.shtml It is said that interrupt endpoint is unidirectional and periodic. Yet, I see in the description for IN interrupt ...
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1answer
54 views

Hardware & software for streaming phone display [closed]

I'm looking to create a projector which projects my phone screen onto a wall. I have a few requirements: I'd like to do it using a projector with its own light source (i.e. I don't want to use a lens ...
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3answers
124 views

What technology is used for authorities to send emergency alerts to mobile phone users? [closed]

Do modern-day protocols that our mobile phones run on eg. CDMA/GSM, 3G or 4G have a emergency break-in/broadcast protocol for authorities to issue warnings to the public? In the recent case in Hawaii ...
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7answers
4k views

Why I2C designed to work with pull-up resistors and not pull-down ones?

I understand that in I2C, SCL and SDA lines use pull-up resistors and the pin drivers are open collector NPN devices which can drive pins to ground. This gives I2C an advantage that the same bus now ...
2
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1answer
759 views

Protocol for RS485 network?

I have to build a sensor network which communicates over a single RS485 bus. The network could have tens of nodes. The problem is that I have to control access to the shared bus and find a way to ...
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2answers
57 views

Which MSC Sub Class is the best for USB 3.0?

I have been looking at implementing the Media Storage Class on a FX3 from Cypress. There is already a pre-written firmware example using MSC BOT (Bulk Only Transport) and SCSI commands and I was ...
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2answers
574 views

How has this Daikin control signal been encoded?

I just installed a Daikin split system (AC/Heat Pump) and would like to control it remotely. There are similar units available which can be controlled with an IR remote, but mine does not support this ...
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2answers
215 views

Decoding a Two-Wire SPI-esque Serial Protocol

I'm working on a project that involves the optical sensor from a mouse. I've got the original control PCB (still populated, save for the optical sensor itself), and I've got the optical sensor on my ...
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3answers
265 views

VGA Image Refreshing

Hey everyone I am looking into VGA protocol. I have researched a lot but only thing I could not figure out is this: Does VGA vertical sync and horizontal sync needs to be sent over and over to keep ...
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0answers
76 views

Whats Reliable Burst Protocol(RBP)?

I couldn't find much details about this protocol than an IEEE paper which I couldn't download. Any quick comments on this?
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0answers
52 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 ...