Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

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44
votes
2answers
13k views

Why are USB devices slower than 480 MBit/s

Motivation With a signaling rate of 480 MBit/s USB 2.0 devices should be able to transmit data with up to 60 MB/s. However today's devices seem to be limited to 30-42 MB/s while reading [Wiki:USB]. ...
29
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8answers
4k views

When should one switch from ASCII to advanced serial protocols?

All my microcontroller devices that communicate with the PC via UART use ASCII strings for sending commands and receiving data (as implemented in Arduino). That's what I learned when I began digging ...
26
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1answer
41k views

How do volume control headphones work?

A recent question over on Android Enthusiasts got me to wondering how volume control headphones work. I don't mean volume control which works by attenuating the incoming signal, but the kind of ...
24
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6answers
10k views

Serial protocol delimiting/synchronization techniques

As asynchronous serial communication is widely spread among electronic devices even nowadays, I believe many of us have encountered such a question from time to time. Consider an electronic device <...
22
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7answers
5k 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 ...
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 ...
13
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2answers
13k views

Rolling Code Explanation

Could somebody explain how rolling code protocols such as KeeLoq work? I understand the basic premise that they use a different code each time so you can't just use replay attack, but I don't ...
11
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6answers
59k views

What is the difference between Ethernet and Serial communication?

All the mouse movements, USB connections and other PC peripherals such as printers etc. are what is called serial communication. One bit per time. So far so good. But when it comes to TCP protocol, ...
10
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6answers
11k views

Good RS232-based Protocols for Embedded to Computer Communication

I'm working on a project that involves a good bit of data communication between a remote Arduino and a computer. The wireless connection is through a pair of XBees, so we have a RS232 link between the ...
10
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2answers
685 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 ...
9
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4answers
32k views

LVDS vs MIPI, what's the difference?

What are the practical differences between LVDS and MIPI? A little background information: I am attempting to build my own projector on the cheap and want to use a nexus 10 LCD panel (2560 X 1600 ...
9
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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 ...
9
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2answers
1k views

VHDL: receive module randomly fails when counting bits

Background This is a personal project; it regards connecting an FPGA to a N64, the byte values that the FPGA receives are then sent through UART to my computer. It actually functions pretty well! At ...
8
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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 ...
8
votes
8answers
11k views

What is the name of the protocol(s) used to let an automatic garage door opener know which button I've pushed on the wall control panel? [closed]

The wired wall control panel in my garage has only 2 wires connected to it. Yet somehow it acts different when I push the big "door" button than when I push the "light" button or the "lock" button. ...
8
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1answer
5k views

Transceivers in the field of FPGAs: When and why will we use them?

I am recently getting myself into the field of FPGA design and development, and lately I've found myself hearing a lot about transceivers. I tried searching the net for some answers about these ...
7
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5answers
3k 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
7
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6answers
4k views

Is it possible to make a USB device that would alter mouse data on the fly?

I have a friend who is struggling to find mouse drivers/manufacturers that support various options for dyslexia. Inverting the X and Y axes are a simple feature that most programs and drivers are ...
7
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2answers
4k views

Is there a standard I2C/SM bus protocol for laptop battery packs

I'm building a laptop with a custom battery pack. I know that the pack has to communicate through an I2C/SM port on the motherboard, but I don't know how to make the bios/os recognize it. Is there a ...
7
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4answers
1k views

Home automation protocols in Europe

Which protocols are used in Europe? I'm more interested in "higher layer" protocols (e.g. light bulb control) than with the physical layer, but those will be welcome too. Does the KNX standard have ...
7
votes
1answer
766 views

MIPI RFFE software implementation

I'm currently trying to implement the MIPI RFFE (As master) protocol on a simple AVR microcontroller, the specs says that the clock frequency can go down to 32 kHz, so I guess this it should be ...
6
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5answers
8k views

DSC Keybus Protocol

I'm plan to interface a atmel avr with my alarm system in home but the issue is DSC has a propriatary protocol between the keypad and the base. So has anyone messed with this before or can give me a ...
5
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6answers
7k views

Manchester encoding

As I understand, in Manchester coding known bits are sent before start a transferring. But I didn't understand why - One of the main benefits of Manchester, is the fact that sync between the two side ...
5
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6answers
1k views

Help with device identification in a chain

So I'm working on a new project where I'm trying to identify devices on a closed protocol "network" of sorts. I'm trying to determine how many devices are out there and unique id's of each device. I'...
5
votes
1answer
802 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) ...
5
votes
3answers
256 views

Determining command constants for serial protocol design

It seems to happen fairly often that I'm working on a system that incorporates a serial (SPI or async) command set. As such, I generally have to put together a set of arbitrary command byte values ...
5
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4answers
358 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 ...
5
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2answers
1k views

Transmitting ASCII 'A' over SPI Protocol

I'm working on a project that involves connecting directly from the TRS jack of an iPhone to a SPI port on a microcontroller. So the iPhone is the master and the microcontroller is the slave So let'...
5
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2answers
3k views

Hart protocol implementation

I would like to implement the HART protocol and am searching for specifications of the protocol. I found that the Hart Communication Foundation manages the protocol and on this page it says that ...
5
votes
3answers
819 views

Method required to enable a toy “vehicle” to follow a “target” wirelessly?

I am trying to create a small robot toy car with the ability to follow a person around, with a range of about 50 m. Ideally the person will be provided with a small transmitter of some kind, and the ...
5
votes
1answer
642 views

DMX512 packet issue (no break?)

I'm not sure if I'm reading this wrong or something, but this is a trace of the DMX packet that's coming from my USB-RS485 module then being converter to UART logic levels for my microcontroller. ...
5
votes
1answer
667 views

Detect Hama IR Remote Protocol

I'm working on an universal receiver and I'm not able to detect what protocol is used by the Hama VRC-1100 MCE Remote. The signal is this: The Time/Div is set to 2 mS and the distance between a ...
5
votes
2answers
762 views

Analyzing the Protocol

I am trying to understand a protocol (shown in figure 1) . For now this I have understood that data is transferred at high to low clock. as shown in figure. and the sync is for every 8-bit. But then ...
5
votes
0answers
145 views

Analyze protocol used for Futaba VFD display, 3 data pins

I take apart a Samsung SMT-C7140 HD Unit (made obsolete by cable company, a shame) and found a nice display that I could probably reuse. It is a Futaba GL07-00006A (13-BT-246GINK). I tried to find the ...
4
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4answers
6k views

uart communication protocol

I'm working on a project where I have to communicate different lengths command from my PC to a microcontroller. (using usb to uart bridge) I already make a litle protocol (start byte, some data, ...
4
votes
2answers
840 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 ...
4
votes
3answers
1k views

Reverse-engineering IR check bits/CRC

I'm trying to build a simple Arduino-based IR remote control for a cheap toy IR-controlled helicopter (same as this one - it's called "Diamond Gyro" or "Diamond Force"). I've decoded the IR protocol ...
4
votes
4answers
154 views

What is the point of “software data protection” in a rewriteable ROM?

I've been considering trying to hack an old '98 era motherboard. The ROM(I presume for the BIOS) is a Winbond W29C020-70. In it's datasheet, there is a thing called "Software-protected Data Write". ...
4
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4answers
4k views

What is the best wired protocol choice for home automation?

I know the X-10 protocol. X-10 is a good choice or is there better?
4
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1answer
1k views

SPI and a Flash memory IC, the basics

In SPI, I have a few questions... I understand how bits are clocked through, but how are bytes are delimited? Is the slave select pin only required for turning the data output high impedance? Or is ...
4
votes
3answers
263 views

How would I software-decode this 260KHz serial stream?

I've probed this serial stream coming out of a scoreboard controller and it seems like a proprietary protocol. How would I go about trying to software-decode this? The start bit is 7.8us long. All ...
4
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2answers
2k views

XBee, how does it deal with collisions?

I'm getting started with XBEE S2 modules and I have a doubt I still couldn't get a clarification, hope you guys can help. I want to have 2 end devices transmitting data to one coordinator, all of ...
4
votes
1answer
2k views

Adding Profibus capabilities to a product

We are currently developing a product and now the "idea" has come up to integrate Profibus since it is quite used in that specific area. Now I was wondering if anyone has made such a product. If I ...
4
votes
4answers
254 views

Low cost/complexity bus for expandable modules?

I'm trying to pick a bus for an expandable system. Requirements would ideally include: Unknown number of modules (potentially up to a couple dozen). Multiple identical modules are allowed (giving ...
4
votes
1answer
2k views

How to reverse-engineer a remote control?

I purchased a few bulbs which are manged via a wireless remote control. I would like to use them with my RPi (to which I would add the relevant transmitter-receiver module). Is there a way for a ...
4
votes
1answer
4k views

Can anyone identify this 433Mhz OOK protocol?

I am working with some wireless devices that use 433MHz OOK transmitters and receivers. They use a simple protocol for the data sent between the nodes. I feel it is reminiscent of common IR remote ...
4
votes
1answer
186 views

Tradeoffs between transmitting and listening with low-power 2.4GHz

On a number of 2.4GHz chips, listening for a signal is actually more expensive than transmitting. If one is trying to minimize power consumption with such devices, to what extent should one strive to ...
4
votes
1answer
180 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 ...
3
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4answers
998 views

Why buy protocol analyzer modules for an oscilloscope?

Scopes with logic analyzer inputs often have optional add-on modules that let them decode various serial protocols: SPI, RS-232, I²C, CAN, etc. Tek and Agilent want around US $700 per protocol family ...
3
votes
4answers
449 views

Dealing with signal noise over 50 foot communication link

Situation: Connecting a motor controller to an MCU. Motor controller is about 50 feet away from MCU. Connected via a single conduit (buried), containing the following cables: (There is no other ...

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