Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

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1answer
39 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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1answer
99 views

I need help to understand a sniffer circuit schematic

I'm an electrical engineering students and for a school project I need to understand a circuit schematic. First, I will provide some context. The school project I'm working on is the modification of a ...
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0answers
32 views

Do modern PS/2 keyboards ignore the RESEND command?

Trying to understand how to correctly implement response to the RESEND (0xFE) command from keyboard host, I've made an experiment: at a certain time, when the (real) keyboard is sending its first byte ...
4
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1answer
437 views

Are USB protocol and connector free or are they patented?

For a hobbyist developing a device, certification is not pleasant. I am wondering if implementing USB in any way is patented or needs a certification? I am concerned about both protocol (USB-2,3) ...
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1answer
82 views

Can I run a DDR4 module at 50 MHz?

I haven't seen any restrictions about minimum clock, but I may have overlooked them. EDIT: The module is a Crucial CT4G4SFS824A, based (this is an informed guess) on 4Gb Micron 512 Meg x 8
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0answers
55 views

Wishbone B4 rule 3.55: Is this for a special case?

Rule 3.55 of Wishbone B.4 states: "MASTER interfaces MUST be designed to operate normally when the SLAVE interface holds [ACK_I] in the asserted state." I read this rule together with permission 3.35,...
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1answer
69 views

Is it possible to program a RFID tag like a microcontroller?

I am working on an RFID project. I want to be able to send specific messages between the reader and the tag or maybe perform my own protocols on it. Is there a type of tag that I can provide some sort ...
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0answers
32 views

How are MBIM transaction ID's supposed to be used?

Situation I am developing a product that will use this Sierra Wireless HL7618RD Cat 1 LTE modem. I am interfacing to the modem over USB using a small SoM running a Debian flavor of Linux. The modem ...
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0answers
14 views

Video AHD protocol documentation/stanard for implimentation?

Im looking for some form of documentation in which supplys the information to impliment the Analog High Definition (AHD) protocol, for knowledge, I am using an FPGA for reading data, and a Swann PRO-...
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15 views

SD controller SD protocol single block read transaction timing

When does an SDHCI controller (3.00 spec) starts reading the DAT lines in a single read block transaction (not using DMA)? Does it wait to receive the full ...
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0answers
53 views

CLK signal on DAT0 line on SD protocol?

I'm facing some problems in the initialization stage of the SD protocol on a custom board, specifically when sending the ACMD51 command and reading the Status Card ...
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2answers
43 views

How does line encoding relate to bus protocols like SPI, serial, i2C, ethernet etc [closed]

I'm referring to line codes like bipolar, machester, miller etc... https://en.m.wikipedia.org/wiki/Line_code How do these line codes relate to bus protocols? Is it another level down? Is it ...
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1answer
94 views

How to best use SPI (master/slave)?

This is a follow/new insight regarding my previous question Messages for SPI protocol. One idea from that question is to use the SS line to know a new message is being sent from the master to the ...
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2answers
59 views

Questions regarding messages for SPI protocol

I want to use the SPI protocol to communicate between an STM32 and Arduino. So I made up some message structure where the first byte is the 'command' byte, and data bytes following. The number of ...
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1answer
143 views

Signal filtering, what's wrong with the circuit?

I have this circuit where I receive a protocol signal: The +L_IN signal is this: This signal has a 28V DC voltage. The signal at ...
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2answers
118 views

Extremely low data rate transmission over long distance for attinys

For a lighting project I need to be able to trigger 20 units every couple of seconds independently which are daisy chained with 1-2 m space between each of them like so: Control station ====== Unit 1 ...
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0answers
87 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 ...
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1answer
63 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
14 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
54 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
21 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
119 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
47 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
41 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 ...
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1answer
127 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
67 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
99 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
70 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
85 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 (...
4
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1answer
165 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
605 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
78 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
45 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
70 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
833 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
78 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 ...
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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
539 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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2answers
2k 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
188 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
70 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
142 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
95 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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3answers
120 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
214 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 ...