Generic $5 128x64 OLED SPI display with Arduino Pro Micro

I bought a couple of ~$5 generic 128x64 graphic OLED displays on eBay to play with. It took some trial and error to figure out how to get the Arduino Pro Micro to talk to them, and there's lots of different information on the net about doing so (probably owing to the wide variety of implementations of these displays and generic controller chips.) This particular one uses the SD1306 controller and is wired for a 4-wire SPI interface. I used the u8glib library to talk to it. The "gallery" page on the library repo provides lots of examples of people's various combinations to make these work. This particular one wasn't shown, but by perusing through the different examples I was able to find a combination that worked. Wiring: I'm using the SW SPI function of u8glib, so I don't have to use the ARM chip's native SCK or MOSI pins. I found that this device will accept data without the CS pin connected (pulled low instead), so I left that out to s...