[GreenKeys] Serially, Are You Syncing or Asyncing?

[ralph irish]

Here is some info on Synchronous and Asynchronous communications techniques.  Our Teletype
systems need a Start and Stop Pulse, which puts them in the Asynchronous category.

73,

Ralph - W8ROI

PS   Is it me or has GreenKeys been somewhat quiet for the past 10 days?  Just an observation,
     here.

R

- - - - - - - -


> From: Hackaday <comment-reply at wordpress.com>
> Date: June 28, 2016 10:03:35 AM EDT
> To: w8roi at wowway.com
> Subject: [New post] Serially, Are You Syncing or Asyncing?
> Reply-To: "Hackaday" <comment+_hf2r4gr8qatrnr0rjc3p5dm at comment.wordpress.com>
> 
> Respond to this post by replying above this line
> New post on Hackaday
> 
> Serially, Are You Syncing or Asyncing?
> by Rud Merriam
> I know you've heard of both synchronous and asynchronous communications. But do you really know the differences between the two?
> 
> Serial communication was used long before computers existed. A predecessor is the telegraph system using Morse Code, one of the first digital modes of communication. Another predecessor is the teletype, which set standards that are still used today in your Arduino or Raspberry Pi.
> 
> All you need is two wires for serial communications, which makes it simple and relatively robust. One wire is ground and the other the signal. By interrupting the power with predefined patterns, information can be transferred over both short and long distances. The challenge is receiving the patterns correctly and quickly enough to be useful.
> 
> I was a bit surprised to find out the serial port on the Arduino Uno’s ATmega328P microcontroller is a Universal Synchronous Asynchronous Transmitter Receiver (USART). I’d assumed it was only a UART (same name, just leave out synchronous) probably because my first work with serial communications was with the venerable Intel 8251 "Programmable Communication Interface", a UART, and I didn’t expect the microcontroller to be more advanced. Silly me. Later I worked with the Zilog 8530 Serial Controller Chip, a USART, the term I’ll use for both device types.
> 
> All these devices function in the same way. You send a byte by loading it into a register and it is shifted out one bit at a time on the transmit (TX) line as pulses. The receiver accepts the pulses on a receive (RX) input and shifts them into a register, which is then read by the system. The transmitter’s job is pretty easy it just shifts out the bits at a known clock rate. The receiver’s task is more complex because it needs to know when to sample the incoming signal. How it does this is the difference between asynchronous and synchronous communications.
> 
> Read more of this post
> 
> Rud Merriam | June 28, 2016 at 7:01 am | Tags: asynchronous, serial communications, synchronous, telegraph, teletype, uart, usart | Categories: Hackaday Columns, Microcontrollers, Skills | URL:http://wp.me/pk3lN-SVS
> Comment	   See all comments
> 
> Unsubscribe to no longer receive posts from Hackaday.
> Change your email settings at Manage Subscriptions.
> 
> Trouble clicking? Copy and paste this URL into your browser: 
> http://hackaday.com/2016/06/28/serially-are-you-syncing-or-asyncing/
> Thanks for flying with  WordPress.com
> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20160628/5fcf61e8/attachment.html>