Main board rev 1

[jkominek]

Place to record necessary changes for rev 1 of the board:

Important

• [x] MicroSD card slot.
• [x] RS485 transceiver SO8 footprint appears to be wrong; awkwardly wide and difficult to solder.
• [x] Compress the board to <= 100x100mm.
• [x] Remove all ethernet
• [x] Expose a couple of carefully chosen GPIO to act as ~IRQ pins for external Qwiic boards. Bring them out on headers, kind of like the switches/LEDs/etc.
• [x] Change the FET footprints to SOT-23-3 to accomodate JLCPCB SMT basic parts library.
• [x] Swap USB D+/D- into the correct positions.

Noncritical issue

• [x] Scoot the +5V and GND silkscreen slightly further away from the power connector.
• [x] Add silkscreen to put the JLCPCB part number under a stack of RJ45 jacks.
• [x] The Qwiic headers will be hard to hand solder. Giving them some more space sort of contradicts the plan to narrow the board, but anything we can accomplish will help.
• [x] Increase the space between the 3.3V regulator, and the power/reset/status header, to ease rework.
• [x] Bump up the size of the electrolytic cap footprints by 1, to better match the cap selection you get in variety packs.

[jkominek]

First batch of changes made in b8bb4f2. It was basically a complete relayout. I stripped all the traces, repositioned everything, and then reconnected it all.

• RS485 transceiver footprint fixed
• Compressed board to 100x100mm exactly
• Removed ethernet
• Changed FET footprints to SOT-23
• Swapped USB D+/D- to correct positions
• Spaced out +5V and GND silkscreen on power input
• Added JLCPCB order number silkscreen
• Spaced out Qwiic headers
• Added some more space around 3.3V regulator.
• Slightly increased size of electrolytic caps.

[jkominek]

2efb067 finishes off the changes.