Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

why so many serial communication protocols

Status
Not open for further replies.
I have this doubt suppose I wanted my own serial communication like say continuous 5 1's followed by say 2 0's as some value. so I can form my own photocol. what is the actual basis of forming a protocol as we see so many serial protocols like rs232, rs485, spi, i2c, can. what are the issues they think before forming any protocols. I see something like driver ic what exactly is driver ic.
 
Read this to start.
 
Certainly you can devise your own protocol.
 
I do a serial protocol... Its 11 bit... 8 bit data and 3 bit address... It works over a 100m cable ( two core )

The "driver" is nothing more than a transistor near shorting he two power wires... At the base end I detect the current being used... 20mA denotes a 1 and 4mA denotes a 0... Nothing new but works a treat....

You can do what you want.... The driver is designed to carry the signal to where it needs to go.. whether its a current signal, voltage signal or wireless signal!!
 
Nothing wrong with rolling your own comms protocols. Depending on what your trying to achieve, and how complex your requirements are, some things you might want to think about up front could be, in no particular order:

Will it be used to communicate one to one (point to point), one to many or many to many nodes (bus or network type environment)?
How far in distance terms must the signal reach before degrading beyond being reliably received?
Over what medium will the communication take place? Wires or Wireless?
What type of Cable or Radio module will be used?
How much data, in bit terms, is required to be sent and received at any one time, or is this a continuous stream of data bits?
How fast must the data be transmitted/ received etc?
Will error detection and data recovery be required?
If a bus/ network type environment, how will you detect and mitigate possible data collisions?

This list is by no means exhaustive, and depending on your goals, may totally be overkill, however, whatever else you do, try to keep your whole vision as generic as possible, you will want something that can be sent over any medium at reasonable speed and be robust enough to recover from data errors, all with minimal changes that account for the medium being used. Most serial protocols go hand in hand with their hardware or physical counterparts, so the resulting protocol is usually a mixture of two things, control bits and data bits :)
 
I see something like driver ic what exactly is driver ic.
Most UART Ic's are either built to a pic or intended to hook up to a μp.
Rather than wind your own, you may still be able to get the standalone UARTS such as the older Intersil IM6402 which suited simple interfacing and took care of all the data clocking.
For the simple 8 bit data you are looking at, RS232 would do it.
Max.
 
My understanding is that RS232 and the others mentioned refer to an electrical standard . for voltage levels and handshaking . protocol relates to the format of the bits transported.
 
There are two major aspects to any communications system, the physical details and the way the data is packaged. For example, RS-232 describes both the voltages and timing of the pulses that represent 1' and 0's (+/-12 V, 4800 baud, etc.) and the data format (start bits, stop bits, parity, number of data bits, etc.). There are plenty of protocols to choose from because when a new one pops up (like Philips inventing I2C to make it less expensive for its signal processing chips to talk to each other) it doesn't automatically eliminate the previous protocols that were in place. Whipping up one of your own is a great way to learn how these things are developed at a level that goes way beyond just reading about them.

In the world of parallel data/address buses, I've designed and built interfaces and devices for 16 commercial and industry standard buses, and created 7 bus systems from scratch for custom situations. Figure out your requirements, evaluate the strengths and weaknesses of the available options, and determine whether or not any of them can satisfy your requirements. If not, go for it.

ak
 
Although people dont design protocols from the OSI protocol family, it would be educational for you to understand all the variables at each layer that ends up with thousands of Standards.

To choose a protocol, you must first define the requirements ( Must Haves vs nice to have)
1) Physical..

...cable type, length, bit rate, , single or differential, binary or dubinary or tertiary or multilevel voltages, low or high impedance, voltage or current levels, one way or half-duplex or two-way full duplex (FDX), then noise immunity requirements etc, desired S/N ratio and Bit Error Rate (BER) with noise present.

2) Data Link ...

... order of bits, order of bytes, word size, message size, redundancy, ( Parity , CRC or ECC or none)
.. functions of bits, bytes, address & data , reliability, ACK/NAK, message transport guaranteed

https://en.wikipedia.org/wiki/OSI_model
https://en.wikipedia.org/wiki/List_of_network_protocols_(OSI_model)
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top