Today was ethernet and some little touches here and there. Connecting stuff to the lattepanda mu, changing some usba ESD diodes, planning, etc.

First, ethernet. I do not understand ethernet. I tried hard to understand and use a TI IC for it and make my own circuit. I couldn’t figure it out. So, I made my own version of a circuit I found on an existing lattepanda mu carrier board - the lattepanda MOKA. https://github.com/piecol/lattepanda_MOKA
It’s a pretty cool project and has good examples of some high speed routing and schematic design.

This is what the MOKA has for ethernet.

And this is what I have. Similar, but I made a fair amount of changes. Notably:
Different ESD diodes, I like the TI ones.
Different AC coupling capacitors, the MOKA used the wrong ones? I guess it wasn’t an issue but they are supposed to be 220nf, not 100nf. Straight from lattepanda/intel, so I know it’s right.
DIfferent resistors to match datasheets better.
Different crystal.
Different pin names of course.

I think that’s it? And I made everything bigger and easier to see. At their core, the circuits are similar, but I made a fair amount of changes. Call it a Reference.
Oh, I also hooked up 3v3 VCC to the ethernet port. For some reason the moka just has a capacitor straight to ground?? Which is a silly mistake and probably a non issue but could affect the performance of your magnetics (if they even get power at all without that… datasheet isn’t very helpful.)

So that’s ethernet! This will be super nice. I am using an IC that supports ethernet evaluation and fancy debug stuff so I should be able to use this for debugging if I wanted to. Good cyberdeck ability.

Next.

I changed my USBA to use the TI ESD diodes from my other pages since they are much nicer than the weird cheapo chinese one that I had before.

Next again!

Some little touches here and there on wiring.

Look! USB has the keyboard wired in! That’s just an example of one little touch. Basically all pin mangement though. Double checking, triple checking, quadruple checking. I will never stop checking.

Anywho, I also mentioned planning. I am switching to Linux. Planning on windows initially was a little silly but I wanted to be able to use fusion360. I could maybe use proxmox with windows? Depends what ram version I get of the Mu. We will see!
This also means I shouldn’t need to run GPS and LORAWAN as USB devices, but rather straight to the mcu over i2c/spi/uart (haven’t decided). Technicallyyyy windows supports that but you need ring 0 level drivers which are incredibly annoying to deal with because of security shtuff. So, I just won’t deal with it! Linux to the rescue. This is probably the right choice for a lot of reasons I have yet to determine.

That’s all for today. Next is gonna be finally tacking GPS and Lorawan I think? Or maybe I put it off more by doing trackball stuff. Though I may just make the trackball a USB module so that I can move it…. We will see.
It’s funny, I am already past 24 hours of work on this… and I haven’t started any routing or cad. None. Zero.
Yippee.