My config for ssd1306_128x64_spi.ino

ssd1306-SPI-custom.ino

// If using software SPI (the default case):
#define OLED_MOSI  D4
#define OLED_CLK   D3
#define OLED_DC    D2
#define OLED_CS    D1
#define OLED_RESET D0
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);