Triggering And Decoding Serial Protocols On An Oscilloscope - Workbench Wednesdays

[@element14presents]

Thank you for checking out the video! For more information on serial buses and a deeper explanation on the I2C OLED address stuff head over to the element14 Community: bit.ly/2OlfjGh

[@qzorn4440]

simply wonderful information and thanks for including pico. also, Siglent SDS1202X-E Decoding is nice. Modbus rtu rs485 is very important on the factory floor and IIOT. 😎 thanks.

[@chrislamb4723]

Thanks for the address finding tip! I look forward to giving that a try soon.

[@navadeep025]

Nailed it! The thumbnail ;)

[@NiHaoMike64]

Also don't forget FX2 and Sigrok for a super budget logic analyzer that is still fast enough to cover the vast majority of hobbyist microcontroller projects.

[@PhG1961]

Excellent !

[@gtag174]

Would be valuable to mention the oscilloscope brand or model that supports reading serial interface signals.

[@bald_engineer]

Since the video wasn't about this specific scope, I didn't feel the need. Also, *most* oscilloscopes today support some form of decode or trigger. But for details, they are in the show notes: www.element14.com/community/docs/DOC-96191/l/workbench-wednesdays-34-triggering-and-decoding-serial-protocols-on-an-oscilloscope

[@surenbono6063]

...I can't understand why 2 different Arduino needs gnd apart from RX,TX wire for communication...hc-12 didn't need any...

[@bald_engineer]

Wires connected to each other conduct current and need a common reference, aka "ground." When moving current through wires, you need a closed loop. RF radiates the electromagnetic waves (mostly) through air. Inside of the TX and RX of the radios are amplifiers that are referenced to the local system's ground. It's two different ways of moving the electromagnetic energy.

[@surenbono6063]

@@bald_engineer ... can't it refer to it's baud rate instead?

[@bald_engineer]

@@surenbono6063 huh? Baud rate is how fast symbols are sent.

[@surenbono6063]

@@bald_engineer ...the rf signal depends on the baud rate to estimate the next arrivals of data and adjust it's clock for each received data .. and didn't need a common ground

[@bald_engineer]

@@surenbono6063 Baud rate is related to symbol rate. That’s a protocol level event. You’re talking about physical layer. As I already explained, RF is a different method of moving the electromagnetic wave. Wired connections depends on a closed physical loop. RF does not.

[@els1f]

Very triggered by this video

[@samsungtelevision695]

Ha saved me from commenting 😄

[@danielv3228]

"Main-Out" "Main-In" "Second-Out" "Second-In" Has that now infiltrated a demo about communications buses? Really? Are the jumpers on my old hard drives also "main" and "second"?

[@armyant7]

They're free to use whatever terminology they want. It isn't confusing to me so I don't see the problem.

[@stuartmartin3408]

Yep they’re totally free to use the terminology they wish. It is however such a shame that we appear to no longer understand context in the language we use.

[@larrybud]

@@armyant7 If you use whatever terminology you want, people won't understand what you're saying. If I name them the whosit and the whatsit, do you know which is which?

[@armyant7]

@@larrybud "won't" -> "may not" Like in this case, did you find it unclear? Depends on how it's done for each case

[@johndripper]

But why use an expensive oscilloscope rather than use a cheap 10$ logic analyzer to analyze serial protocols? Any benefits?

[@MrWaalkman]

Well, in the example he triggers the scope off of a sine wave. That's not something that can be done with a LA. Sure, you could build something that would create a trigger for the LA to use, but the LA wouldn't be able to do it by itself. But between an LA and a scope, I use my scope far more often than I use my LA (a HP 16900A). So having this feature on my scope (a Rigol 1054Z upgraded to a 1104Z) is a nice thing to have on something that you are going to own anyway. As for prices, the (new) Rigol can be had for $350, and hacked to perform as if it were a 1104Z for free. The (used) 16900A was $300, but you have to be sure that it comes with the pods, and at that price it usually won't. And you have to find one that has the cards that you want, and again, at that price you usually won't. So you are going to spend more for the LA if you want something nice. The 16900A was purchased as an upgrade to my 16702A, and since the 1690x series uses the same cards (except the scope card) as the 1670x series I didn't need to worry about pods and such. And the final thing to compare is shipping. the HP LAs are boat anchors and you will most likely pay a small fortune to have it shipped to you. The Rigol, not so much.