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LaPOD: Low cost Logic Analyzer probe for MSO5k, DHO900 and more!

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S. Petrukhin:
I've never studied HDMI standard, I don't know if it uses LVDS.
But I didn't see any soft cables.
When you receive the finished device, show a photo and share your opinion on how the 4 plugs in the adapter behave.

The IDC with clamps is very reliable and the 6 cores of a flat cable can be very flexible, especially in 500mil step.
You could look at RJ11 as an add-on. But it will take 16 of them...

For training and pride in work, this is an argument.  :-+

jsobell:
I like the look of the design, although finding some of these components is a real pain!
Quick question, in the SN65LVDS pod, why are EN and /EN both held high at 3.3V?

J.
Edit:

I see why. Your design is for the SN65LVDS391 and not the SN65LVDS047 version.

jsobell:
Actually, the KiCad part in the schematic is wrong. It should be SN65LVDS391, and not the SN65LVDS047W in the diagram.
The 047W is a 5V part with different pinout.
LCSC don't have any (surprise!) but if you use the SN65LVDS047W then I guess you can do the old -2.2V trick to get over 5V, but you'll also have to fix pin 8, as it won't work if it's high.

Cheers,
 Jason

oliv3r:
Thanks for looking into this! I think I also see the error of my ways :) I took the kicad build in symbol for the quad SN65LVDS, because it was much prettier drawn. As you stated, it is a different part!! SN65LVDS047PW which is not what I intended. I wanted it to be the SN65LVDS31D (but have to tripple check that now too) as you rightfully stated! I'll use the ugly symbol from lcsc for the actual part, and draw it prettier instead.

Thank you! This is golden feedback and saved me a lot of agony!

As for parts availability, those TI parts where a problem ever since the component shortages. digikey/mouser should have better availability I've been told. But I prefer to at least put all BOM parts as LCSC parts for now. Don't thin it's useful to use internal part number for each vendor :(

As for tying both EN and !EN to 3v3, the datsheet has a truth table, where it states that if EN is high, !EN is a 'irrelevant', and I wanted the pin to be a well defined value and not floating. But on second thought, might as well tie it to GND instead.

oliv3r:
So, https://climbers.net/sbc/clone-pla2216-logic-probe-analyzer/ is where I got the sn65lvds idea from. The only 'problem' is the termination resistors. Which now sit close to the sender, rather then the receiver. But we can't put them near the receiver for obvious reasons.

What's confusing me right now, is that Nikki's pinout of the SN65LVDS doesn't match what's in the datasheet. His pinout is much 'easier' to use, all diff pairs on one side ...
   C354139 is the SN65LVDS391PWR, TSSOP with a nicer pinout. C3239334 is the one I've used, SN65LVDS31D, with the alternating pinout. So .. I'll do it again, this time with the right part :)

So I've reworked it, but didn't do the whole '2 footprints' solution. A, because it makes routing harder, and B, hopefully the shortage issue is less of a problem.

Besides, doing a SOIC variant of the PCB is always an option.

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