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Forum Index : Microcontroller and PC projects : UNIO Cfunction - quick question....

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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9610
Posted: 12:25am 10 Feb 2018
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Hello folks.

This is mainly for Geoff, unless anyone else knows the answer.

When using the UNIO, the PDF for the Cfunction says that the data line "Should be short and routed away from other signal lines."

How short?

Does anyone have a reference point for 'Short'?
Currently, I keep this track within 20mm pin-to-pin(shorter if possible) and I try to ensure a ground-plane on either side of this track for it's entire length, but some kind of standard length NOT to exceed would be helpful to know, as then I would know if I could put the device further from the MCU. Even at 20mm, I am wondering if this is too long a track.

I know that the UNIO is very sensitive, but just how much can you really get away with?
Smoke makes things work. When the smoke gets out, it stops!
 
TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283
Posted: 01:27am 10 Feb 2018
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My test setup had flying leads about 100mm long.


20mm should be OK

Jim
VK7JH
MMedit
 
Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3292
Posted: 02:34am 10 Feb 2018
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I don't have a clear answer. When I was developing the UNIO driver I had a very hard time getting a reliable response from the device and the driver now contains a number of measures to address that (like retrying multiple times).

I'm not sure what the actual problem was but, at the time, I suspected that noise on the signal line was the issue - hence my warning. I believe that the measures that you have taken is as good as it can be so you should be safe.

Geoff
Geoff Graham - http://geoffg.net
 
Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9610
Posted: 04:24am 10 Feb 2018
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@ Jim: Any problems at that length?

@ Geoff: Thanks, so noted.
Smoke makes things work. When the smoke gets out, it stops!
 
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