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Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

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0answers
27 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
146 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
2k 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
106 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
30 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
34 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
38 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
823 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
74 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 ...
14
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1answer
1k 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
330 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
11 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
430 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
116 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), ...
1
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1answer
63 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
39 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
106 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
60 views

busy bit of SD card is always one during voltage negotiation

I am working on SD card. Can anyone tell why host is unable to send CMD2. Are my arguments what I am sending from host are correct? In this, when the host is sending the following set of commands ...
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0answers
50 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 ...
1
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1answer
55 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
101 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 ...
1
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1answer
133 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
114 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
143 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
113 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
52 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 ...
-3
votes
3answers
121 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 ...
19
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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
554 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 ...
1
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2answers
54 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 ...
0
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1answer
436 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
195 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
225 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
70 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?
2
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0answers
48 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 ...
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1answer
39 views

How to set a value of JESD

I'm trying to connect an ADC with an FPGA via JESD, but I'm not able to set a relevant parameter on in. Here is the link of the datasheet, where in the page 92 there are several parameters. In order ...
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1answer
222 views

WiFi modules only doing PHY and Data Link Layer

Problem Statement: Need a WiFi module that implements just "Data Link Layer Protocol" after taking in data serially. I am trying to implement all the stacks(Application Layer, Transport Layer and ...
1
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0answers
247 views

CAN Bus Debug MCP25625 CAN to SPI to USB (MCP2210)

I am trying to build a CAN - USB converter using the MCP 25625 chip to convert CAN to SPI first and then receive/send the SPI data on an MCP 2210 chip of SPI interface and consequently convert to USB. ...
1
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1answer
283 views

Questions about SE8R01 (NRF24L01)

Soon I will receive some (2.4 GHz wireless) SE8R01's to be used in my new project (using Arduino). The datasheet can be found here. In my project I want to use several devices, that needs to send ...
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2answers
200 views

No ACK from slave device

What are the possible problems for slave to not give ACK (pull down SDA line) after 8 bits of data? I can see 8bits (slave address) with osciloscope, but the ACK is high at 9th bit clock pulse, why?
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1answer
148 views

I2c slave address confusion?

Can someone explain which address will be used for ADV7511 for I2C if it is stated that it is either 0x72 or 0x7a in adv 7511programming guide [page 16]? If I am right, we send 8 bits per transfer, ...
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1answer
38 views

Plug n' Play protocol for synced devices

I'm developing a highly customizeable lights system for emergency vehicles that consist on a series of devices, all of them in sync, with the posibility to program diferent sequences (of a moderate ...
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4answers
203 views

Device discovery on simple bus

I am currently facing following problem: there is a system, which consist of one master device and some number of slave devices (all those devices have tiny MCUs). They communicate with some custom ...
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2answers
57 views

How to research Hardware Theory in Vision Systems [closed]

I am trying to read up on the theory (for Hardware) of how hardware works in a Vision/Camera System from the Camera Sensor all the way to the pixels on the screen. I dont know what to start googling ...
0
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1answer
1k views

Official PS/2 Keyboard Protocol [closed]

I would like to learn the protocol for a PS/2 keyboard, but I have been unable to find any official documentation. I have seen these websites: http://www.computer-engineering.org/ps2keyboard/ http://...
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0answers
63 views

Local Interconnect Network(LIN) default status

How does slave identification takes place in LIN protocol by the master ? What is the default status of a LIN bus ? How are collisions avoided in LIN ? What is the role of Sporadic frame ?
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2answers
145 views

Can anyone identify this type of communication protocol?

First off I'd like to say that once I figure out what kind of communication I am dealing with here, I'd like to change the title of this question to something more appropriate (or if someone else ...
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0answers
44 views

What is a typical error rate of local protocols?

I am totally a newbie in EE and this question itself may well be too broad or flawed. Please feel free to improve it. By a "local" protocol I mean protocols/interfaces/buses that are mostly used ...