SSD1306_SETCONTRAST, 0x7F, // contrast level 127
SSD1306_SETPRECHARGE, 0xF1, // pre-charge period (1, 15)
SSD1306_SETVCOMDETECT, 0x40, // vcomh regulator level-
SSD1306_SETCONTRAST, 0x7F, // contrast level 127
SSD1306_SETPRECHARGE, 0xF1, // pre-charge period (1, 15)
SSD1306_SETVCOMDETECT, 0x40, // vcomh regulator level-