In https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf I see the following:
• Power supply
o VDD = 1.65V to 3.3V for IC logic
o VCC = 7V to 15V for Panel driving
I'm using my SSD1306 with an ItsyBitsy M0 (SAMD51) which operates at 3v3 but provides both a 3v3 and a 5v output. I've connected the pullups for the I2C communication (SDA & SCL on the SSD1306) to 5v via 4.7k ohms resistors. And I've connected VCC on the SSD1306 to the 5v pin also. Everything is working fine although I'm concerned about the longevity of the display.
With respect to how to do this correctly, i.e. within the specifications provided by the manufacturer in the datasheet, I'm thinking that the pullups should be connected to 3v3 output instead of the 5v output. And I'm scratching my head with respect to what I should be using for the SSD1306 VCC; is that 'panel driving'? 7v - 15v? Any thoughts are appreciated.