Questions tagged [protocol]

A protcol is a ruleset for formatting and exchanging messages.

Filter by
Sorted by
Tagged with
26
votes
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
votes
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 <...
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]. ...
9
votes
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 ...
10
votes
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 ...
13
votes
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 ...
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 ...
3
votes
1answer
658 views

Reverse-engineering asynchronous serial protocol for EcoSmart Tankless Water Heater

I am trying to reverse-engineer the remote control protocol for my EcoSmart Tankless Water Heater. Unfortunately, the remote control device is no longer available for purchase, and the manufacturer ...
5
votes
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'...
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 ...
2
votes
2answers
9k views

SIM card communication protocol

My board contains an STM32 (manual here) and a SIM card reader (manual here). I need to write drivers to test that the SIM reader is working an properly communicating with the STM32. However, looking ...
2
votes
2answers
95 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 ...
2
votes
0answers
581 views

Which serial protocol or encoding scheme does this scoreboard use?

I am trying to decode a signal stream coming from a Nevco scoreboard controller: Packets like this are sent every ~2.7 ms. I suspect it is some sort of UART signal because it is on the RX line of a ...
2
votes
1answer
281 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
vote
1answer
475 views

motion detected protocol

Is there a standard protocol for motion sensors, PIR sensors, etc. to tell parking lot lights, etc. that motion has been detected, so the lights need to turn on? I'm not asking for protocols that ...
1
vote
1answer
235 views

Help with this protocol - LCTC

I have a 640x200 monochrome display from a HP 200LX palmtop computer. On its PCB I can see two types of ICs: HD66204TFL and HD66205TFL from Hitachi. Here is its schematic (it has 200 px not 240 as in ...
0
votes
1answer
327 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, ...
0
votes
1answer
328 views

Since SPI contains data and clock, this makes it “source synchronous” doesn't it?

I read in a Xilinx application note that as data rates became faster became developed source synchronous transfer technique and later came the self-synchronous methods that make use of 8b-10b or some ...