I got some cheap perfboard and noticed how spoiled I was with the exact spacing on my mouse (2.54mm in both directions). None of my boards with pins fit, and I thought I was out of female headers. Then I found some baby 1x2 and 1x4 headers and decided to start a header farm.
The new sockets work fine.
I had this briefly working before, then when I set it up again, I got
nothing. I thought I had blew up a board and totally missed the blue
smoke. I checked everything with a meter a hundred times, and
re-soldered everything three times. This is what I came up with.
This doesn't work:
I am thinking its interference in the shape of the SPI wires, even though the boards are so close to each other. (Blue=3.3V, Green=Ground.)
Am I wrong?
- MISO crosses over MOSI
- SS goes around MISO on the Teensy side.
- SS crosses over MOSI
- MISO goes around SS on the USB Shield side.
(This makes more sense now that I see it on paper.)
This is very scary for me because I am just starting to play with KiCad, and would hate to order a board that had this problem.
Would a board with a ground plane and no “crossed wires” help so much that the shape wouldn't matter?
Are there board designs that are less SPI friendly than others?
I used LibreOffice Draw to map the pins and wires upside down.
Rotated diagram matches wiring pictures above:
I cut the VBUS jumper on the USB Host Shield that supplies power to the host connector, added a USB hub for power instead, and put in a 100uF cap, as recommended here:
Even though the Stickvise comes in handy most of the time...
but I prefer to get the spacing right for pins here first.