SSD1306 128x64 SPI OLED Display

Hardware

These displays use the SSD1306 controller: https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf

The following is from the SSD1306.pfd document:

8.1.3 MCU Serial Interface (4-wire SPI)
The 4-wire serial interface consists of serial clock: SCLK, serial data: SDIN (MOSI), D/C#, CS#.
In 4-wire SPI mode, D0 is used for SCLK signal, D1 is used for MOSI. For the unused data pins, D2 should be left open.
The pins from D3 to D7, E and R/W# (WR#)# can be connected to an external ground.

Table 8-4 : Control pins of 4-wire Serial interface
Function        E(RD#)	  R/W#(WR#)   CS#    D/C#   D0
Write command  Tie LOW   Tie LOW      L      L      ↑
Write data     Tie LOW	  Tie LOW      L      H      ↑
Note
(1) H stands for HIGH signal
(2) L stands for LOW signal

RES#   This pin is reset signal input. When the pin is pulled LOW, initialization of the chip is executed.
       Keep this pin HIGH (i.e. connect to VDD) during normal operation.
D/C#   This is Data/Command control pin. When LOW, it indicates a command to be sent to the command register. 
       When HIGH, it indicates data.
       In I2C mode, this pin acts as SA0 for slave address selection.
       When 3-wire serial interface is selected, this pin must be tied low (connected to VSS).
CS#  This pin is the chip select input. (active LOW).

NOTE: This device uses SPI mode 0.

For this exercise, I used the SPI (4 wire) Hardware interface, with reset (RES#) added. (I don't believe MISO is used.)
According to the datasheet, the maximum SPI clock frequency is 10MHz.

Connections
Board	       MOSI    MISO	SCK	RES#	CS#	D/C#
Arduino UNO	11	12	13	8	7	6

Software

For Arduino, the Adafruit SSD1306 library, version 2.4.2, works very well.  

Additional Resources

https://learn.adafruit.com/monochrome-oled-breakouts/wiring-128x32-spi-oled-display