OLED 4pin I2C (GND VDD SCK SDA) with Photon [SOLVED]

[ScruffR]

SPI would at least require three lines (CS, SS, MOSI)
And these are A2, A3, A5 on the HW SPI interface.

And as it happens very similar questions where asked before

Adafruit SSD1306 [SOLVED]

The Adafruit_SSD1306 library that can be found in Particle Build (Web IDE) does work for the display coming with the kit. If building in Particle Build (Web IDE) you need to change the includes in the demos to // e.g. ssd1306-128x64-spi.ino #include "Adafruit_SSD1306/Adafruit_GFX.h" #include "Adafruit_SSD1306/Adafruit_SSD1306.h" If building with Particle Dev or CLI just leave them as they are For all IDEs do the wiring like this // use hardware SPI // OLED_D0 -> A3 (SPI CLK) // OLED_D1 -> …

But if you only have four pins you are not dealing with SPI but with I2C I'd say and that would be D0/D1 for SDA/SCK.

Providing a link to a datasheet for your exact board would remove all need for guesses.