SparkFun According to Pete 9-17-12: Serial Communication Demystified

According to Pete is a bi-weekly video segment starring SparkFun Director of Engineering Pete Dokter. In this video series, Pete addresses common engineering questions, discusses current projects, and explores the wide world of embedded electronics!
Tags: ATP
Talent: Pete Dokter

[@vaishakhmonti]

Don't get fooled by the lackadaisical and even casual presentation. It's loaded guys. Loved the scope bit. Appreciate the effort man! Keep em coming.

[@haochencui4066]

Finally I understand serial communicaion. Thank you sir.

[@75blackviking]

Thank you for the really helpful explanation! Great vid.

[@johanburger6109]

Well said mate well said, besides understanding something so that you can fix it you also need the knowledge to expand on design in the future

[@psmith6689]

Much more enthusiastic than my embedded systems professor. As for the reason for multiple stop bits, my very old professor mentioned that it had something to do with older devices, specifically teletypewriters.

[@atiqahmad5342]

This is really very good video. I was trying understand the basics of serial communication and it helped me very much.thanks pete

[@carlinhosff]

the best explanation about UART I've ever saw! Can you give us, on the next one, a example of a microcontroller interfacing with a computer? Thx!

[@ZaragonArt]

I believe two stop bits were originally for the original mechanical teletypes tto print the received character before receiving the next character.

[@tomkeyser8384]

Back in the OLD days.... Baud was 110, used for transmitting teletype. Actually before that baud was 33. Baud being is signal transitions. Back then being sent across telephone grade lines. really bad quality lines with analog repeaters that needed to be manually tuned, So, line noise and harmonics were horrible on these lines. Parity and stop bits were definitely required just to get a byte across the circuit reliably, usually being repeated several times.

[@GordieGii]

I suspect the reason 2 stop bits is a thing is because back in the dark ages some receivers needed a little extra time at high voltage for the start bit detector circuit to reset or time to transfer from the shift register to the receive buffer before the next string of bits started coming in. Also, in my experience (mostly PLC and HMI programming software) the com parameters would be [baud] 8n1 (or 8o1) not 8/1/N, because that's the order the bits come in. (DPS) Great video.

[@qzorn4440]

hey dude your head is on backwards or maybe it's the hat? ha ha great video. i work on a x-ray camera that uses the RTS, CTS, DTR, DSR pins as pause and run. thanks a lot...:)

[@selvalooks]

unforgettable explanation thanks !!!!

[@Dirtdigger257]

Great vid i got inspired half whey through broke out the oscilloscope measured the baud rate did the math and it all made sense. Then watch the rest of the video and you ended up doing what i just did lol. Thank for the vid you made it easy to understand.

[@ITZMEEZYUBEEZY]

This is the same technology used in cars (uart) Its how crankshaft/camshaft position sensors and wheel speed sensors communicate with the powertrain control module or body control modules.

[@SparkofMagic]

Great Explanation. Thanks Pete. P.S. looking forward for the next video.

[@MurrayPearson]

I assume the Arduino pins used are TX and RX (pin 1 and 0 on my Duemilanove clone)? Suppose you had three Arduinos and you wanted to talk between them with UARTs for some reason (obviously this can be handled with I2C, but we’ll ignore that for now), can you have multiple serial I/Os on one µcontroller?

[@elkingthemc]

loved this thank you!

[@hertelfrank]

Nicely presented!

[@thijss1170]

This is better than my university class ...

[@Mahbub_Nazmul_Eng]

Really it's a greag video to learn easily. Thanx sir.

[@yellowcrescent]

Using a USART in synchronous mode is just like using a serial shift register or other synchronous serial comms (like SPI). Instead of just RX/TX, you've also got CLK (XCK), which is your clock line (baud rate)... One device is the master (clock generator), while the other(s) are the receivers which use the clock as the baud rate reference. Although you can do this without using a USART and bit-bang it just as well....

[@carrierspace]

Can we get more videos like this please.

[@nathanlilienthal1604]

You do the same thing I do when spelling words. Love it. Also great videos.

[@90chevytruck]

How is that ATTEN oscilloscope?? Is it good compared to an Owon brand or Rigol?

[@MurrayPearson]

Thanks, Lawrence. I was actually thinking of a star-shaped cluster of Arduinos - one master controller driving specialist subsystems on separate machines. It looks like this could implement that nicely - or, there’s always I2C. :-)

[@MohammedGamal5]

A-W-E-S-O-M-E : one byte at a time xD

[@givenmahlangu9221]

😅🤣🤣

[@sigalgalkin]

THANK YOU. ENJOY SUDY FROM YOU. I DO HAVE A QUSTION: will it work with lego (simens)? i do have a sierial adaptor and my computer have usb. thank you again

[@4lifeNerdfighter]

You need to also do a video on USB protocols.

[@L1Christopher]

TY Pete

[@geetasitaprao5163]

truly inspiring...i want to study the communication between pc and smart ups connected by serial interface ,db9 at ups end and db25 at pc end...how can i monitor communication between them...

[@kamotecues]

very informative. thank you sir

[@lawrencejob]

Yeah, it'll work but it will saturate the ports on the 'server' Arduino. Even without UART, you're making a very expensive project -> using multiple Arduinos (unless you have to) isn't very cost effective at all.

[@mokmo23]

lookimg forward to the part on I2C

[@lawrencejob]

If you don't have a capable Arduino, check out (Google) 'Arduino Software Serial'. It only has two physical ports but, being a microcontroller, you can simulate it.

[@wardcampbell5885]

O my!... Now I know everything!

[@Galfonz]

Avionics uses parity. Wouldn't want a bad byte to cause your plane to go down instead of up. The UART is 32 bits. Google ARINC-429

[@johnrees44..G4EIJ]

Many thanks from an 'old timer' who thought he understood serial☹️....

[@yuanchenghe8592]

AAAAAAAAAAAAAAAAAAAAAAAWESOME!!!!!

[@sagnikpradhan3594]

I have never heard of USART..

[@HemaBasha33]

U really really look like johnny depp :) nice video

[@alcampbell]

i was gonna like this but your like hand said 666 LOL.

[@dubbbear]

radical

[@thenerdyouknowabout]

Never used usart

[@AxelWerner]

dual isdn is just 128k max. in the us even less sinxe they often only got 56k per chan.

[@angelogmassolin5056]

I know I really late on this one .... he has no idea on the history of data communications .... In the beginning ... machines or teletypes would send out the information bit by bit each bit was short and went out all messages were created on punched tape ... Paper tape and ir depended on the vintage the old machine used 5 bit for each character ... the they added more characters so that they could send more descriptive messages and went to the 8 bit code ASCII and there are many dielectric of ASCII .... the the computer , or electronic communications evolved and they invented the UART ... this has been around forever at the same time the USART was developed ... the reason for the UART is that machine to machine communications is very slow and computer to computer is very fast so they needed something to store the character until each bit was received and then sent to the next computer ... the BAUD rates hes is talking about .. WELL they were SLOW and started at 300 then went to 1200 the 2400 then 56000 then up and up 96000 then higher com lines in the past were bad and noisy so the slow speed to-day they are still noisy but at the sending end all is encoded from analogue to digital before it leave your home or place of business ... I could go on ... but that is enough for now ... OHHH the USART was ment to be used computer to computer where they could send the characters and clock them at computer speeds but they found it still not practical ....