Ethernet connection with straightthrough

Diabolus
 
Posts: 1
Joined: Sat Nov 15, 2014 11:58 pm

Ethernet connection with straightthrough

Sun Nov 16, 2014 12:12 am

Hi,

I wanted to test ethernet on my vocore without the dock.
I cut a ethernet cable and connected it to the vocore.

This is how i connected it.
wire 1 (White/orange) -- p4TP
wire 2 (Orange) -- p4TN
Wire3 (white/green) -- p4RP
wire6 (green) -- P4RN



Is that no enough or do i need to enable it somewhere else?

Pyrofer
 
Posts: 61
Joined: Tue Oct 21, 2014 11:35 am

Re: Ethernet connection with straightthrough

Sun Nov 16, 2014 10:48 am

You need Ethernet magnetics and a 1.8v pin on the centertap.

Look on RS/Digikey/Mouser/Farnell etc for an RJ45 with integrated magnetics. There will be 3 pins for Rx and TX. Each centertap pin goes to 1.8v then it all works. Without that you get nowhere.

Peter
 
Posts: 14
Joined: Sat Dec 06, 2014 6:00 am

Re: Ethernet connection with straightthrough

Tue Jan 06, 2015 7:49 am

What kind of minimum circuitry would I need for a PCB to PCB ethernet cable? (ca. 5cm in length)
I tried to wire it directly but no link is detected.

Peter H
 
Posts: 58
Joined: Wed Nov 12, 2014 10:24 pm

Re: Ethernet connection with straightthrough

Tue Jan 06, 2015 11:45 pm

Do you definitely need Ethernet? It would be very easy to make a serial connection at that distance.

Pyrofer
 
Posts: 61
Joined: Tue Oct 21, 2014 11:35 am

Re: Ethernet connection with straightthrough

Wed Jan 07, 2015 1:52 pm

As I said, if you want Ethernet then you need the magnetics with 1.8v on the center tap.

You can buy "magjack" RJ45 ports with the magnetics built in which is what I have used on all of my VoCore boards.

Peter
 
Posts: 14
Joined: Sat Dec 06, 2014 6:00 am

Re: Ethernet connection with straightthrough

Mon Jan 26, 2015 2:04 am

Did anybody successfully connected to ethernet without magneticks/rj45 jack yet?
(which should be possible - see TI application note www.ti.com/lit/an/snla088a/snla088a.pdf )

Greenwire-Elektronik
 
Posts: 101
Joined: Thu Dec 04, 2014 6:31 am

Re: Ethernet connection with straightthrough

Tue Jan 27, 2015 9:22 pm

Peter - this app note is only applicable for TI products - you really should think about using magnetics - at least for ground compensation current which could damage your circuit.
Buy now - breakout board for VoCore to easy adapting your idea!

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Ruphobia
 
Posts: 18
Joined: Fri Jan 30, 2015 4:07 pm

Re: Ethernet connection with straightthrough

Wed Feb 04, 2015 8:57 pm

I've wondered about doing this for years with various little Ethernet boards; This would be great for daisy chaining or cluster computing back plane, small robots, etc. Did you ever make this work?

SteeevO
 
Posts: 4
Joined: Wed Aug 26, 2015 5:09 pm

Re: Ethernet connection with straightthrough

Wed Aug 26, 2015 9:23 pm

I've also been having this same problem.
I didn't realize that more components were required.

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