Update EG4.md to include information for Raspberry Pi Can Hat

[Crash-GHaun]

Spent some time troubleshooting an issue I had with connecting my Raspberry Pi Zero. Turns out it was just user error / improper pin-out.

Figure I can save someone time next time by including this documentation :)

[HotNoob]

do you have a multi-meter?

RS485B is typically negative
RS485A is typically positive

it's counter-intuitive.

to best avoid confusion, if you could verify that the eg4 documentation is correct. that would be great.

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and then,
is this the specific can hat? just what shows up in google.
https://www.waveshare.com/wiki/RS485_CAN_HAT

and then for device specific instructions such as the raspberry pi can hat
define rxd / txd as B/A? or just document if rxd / txd should be positive/negative.

[Crash-GHaun]

EG4 documentation doesn't specify the other end, though looking at the cable they provide it is reversed on the other side.

The problem here isn't specifically EG4, it's the fact I was using a Raspberry Pi CanHat and it couldn't communicate unless I swapped wires.

[HotNoob]

cool. i just updated it to be a more general warning; to try not to confuse people too much.

[Crash-GHaun]

I think that's better wording for sure!