AVR Freaks

Can retrofit most any MCU.

Advanced Examples | Getting Started with Configurable Custom Logic (CCL)

E5's XCL doing 2Mbps(!!!) FSK, appnote to follow | AVR Freaks

AT01084: XMEGA E Using the XCL Module | Application Note | Microchip Technology (page 31 for Manchester)

Quadrature | GreenPAK Application Notes | Dialog

edit :

Split-phase Manchester to Split-phase Mark code in GreenPAK | AN-CM-264 Serial Line Coding Converters | Dialog

Full wave rectify with a schottky bridge into an opto-isolator?

Edit: would only work with single ended signal.  True differential would be a no go.

such that the incoming signal can be either polarity, ie idle line is high or low

You request doesn't quite make sense....if you are making code for both ends (manchester, spi, pwm, whatever)  wouldn't you control the polarity?  Why/how would it change?  Is there a possibility of an inverting  buffer box being used?

Is there an idle time that is long enough to identify unambiguously that it is the idle? For example, if start conditions immediately follow stop (with no more than 1 bit time between), then, with async serial, you cannot tell idle from possible valid characters. This would push you to some coding that is inherently polarity insensitive. One of many possible transmission methods that might satisfy this is AFSK (though a bit difficult at 5Kbyte/second and which would likely require additional hardware at each end). 

I am, I admit, a bit puzzled about the fixation on an unpolarized connector. Is it because of legacy equipment? If so, do you have a way to modify the encoding used by that legacy equipment? To me, updating firmware in legacy equipment in the field has always been much harder and more costly than replacing a bit of hardware, like a connector, that any journeyman industrial "mechanic" could handle. I spent 15 years in the security industry so I've dealt with similar challenges. The only trick is finding a connector that is simple enough to install in the field without many tools besides a hammer and a pair of channel-locks. They ARE out there!

Jim

Why would you do that?

If you have to, could you make the connector symmetrical - so the polarity doesn't  change with changed orientation ?

eg, a 3-pin header:

• centre = GND;
• both outside pins are signal.

 +-------+--------> signal
 |       |
 |       |
 O   O   O
     |
     |
     +------------> GND

I skimmed through this thread, and saw nothing mentioned by the OP that the remote device is to be powered by the opposite side.  I also saw nothing to lead me to believe that this is bi-directional data so my misguided thoughts shall focus on a two wire, unidirectional interface.

As ghrote mentioned an optocoupler would be the ideal solution.

This one:

https://www.mouser.com/ProductDe...

Can support up to 10MBaud so thats way over the range needed for the project and had the ability of non polarised input with the back to back LED's in the input stage.

Digikey had another one that supported up to 10KBaud, but I am having a tough time finding it and it was darlington output not logic.

So, if the non polarised connector is simply feeding SIGNAL, and SIGNAL COMMON, go with Ghrotes suggestion and you should be good to go.

Now, if your data is bi-directional and the connector is non polarised, THEN it gets a little sticky.

Jim

The op say he needs to definitely correct for an electrical polarity issue, rather than a logical issue, but perhaps still wants an option to control logic polarity??  Unless using differential signals one is not the same as the other!  So perhaps a combination of these solutions (electrical & encoding) is in order. 

avrcandies wrote:

 

such that the incoming signal can be either polarity, ie idle line is high or low

You request doesn't quite make sense....if you are making code for both ends (manchester, spi, pwm, whatever)  wouldn't you control the polarity?  Why/how would it change?  

Non-polarised connectors on the interconnecting cable. 

Ouch, that made my head hurt.  I guess I have nothing to offer here.

Once I realised what Brian is working with I too got nuttin'.  Hence my reference to TORBY as he has done all sorts of stuff with AVR's and that communications system.

Jim

why don’t you just click the link instead of being lazy about it?  Asking for a friend.

jim

I think you are missing my point.  The OP has provided a link to the system they are interfacing with, and it’s not a simple as many here think.  So, rather than make this a longer than already is thread, trying to explain the system, you can click on the link and review the schematics and read the documentation explaining the operation.  Much more efficient than the OP trying to explain things over and over.

lazy is asking for schematics and information, yet not following a link that the OP provides to the requested info.

cheerio,

jim

Differential Manchester is in 10BASE-T1L auto-negotiation; can supply at least 1 watt to the remote over 1 kilometer.

Microchip Technology has 100BASE-T1 PHY (automotive use case); don't know the current status of their 10BASE-T1L PHY.

The New 10BASE-T1L Standard—Has Anything Changed? | Analog Devices

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Can I Also Implement the Power Supply to the Devices via the “Two Wires”?

Single-pair Ethernet PHY Offers the Industry’s Leading Ultra-low TC10-compliant Sleep Current and is Functional Safety Ready | Microchip Technology

LAN8670/1/2 Family of 10BASE-T1S PHYs (Microchip Technology)

GitHub - Microchip-MPLAB-Harmony/net_10base_t1s: Harmony 10base T1s solutions