SSD1306 OLED display 128×64 (I2C)

A 128 × 64 dot OLED screen whose dots light up on their own (no backlight). It talks to the ESP32 over I2C (only 2 data wires: SCL and SDA). The ssd1306.py driver does NOT come in the firmware: copy the file to the board first. You draw in memory (text, dots, rectangles) and it only shows on the screen with oled.show(). Careful: the pin order changes from maker to maker (VCC and GND swapped).

Pinout

Pin	Connect to	Note
GND	GND	check the order printed on YOUR module
VCC	3V3	on some modules VCC comes before GND
SCL	GPIO22 (wiring used in the example)	I2C clock
SDA	GPIO21 (wiring used in the example)	I2C data

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MicroPython example

# FIRST: copy ssd1306.py (micropython-lib) to the board — it does not come in the firmware.
from machine import Pin, I2C
import ssd1306
import time

# wiring used here (common on the DevKit): SCL on GPIO22 and SDA on GPIO21
i2c = I2C(0, scl=Pin(22), sda=Pin(21))
print(i2c.scan())  # the OLED answers at 60 (0x3C)

oled = ssd1306.SSD1306_I2C(128, 64, i2c)  # address 0x3C
oled.fill(0)  # clears everything (in memory)
oled.text("Hello, ESP32!", 0, 0)  # the 8x8 font has no accents
oled.rect(0, 16, 128, 48, 1)  # frame
oled.show()  # now it shows on the screen

n = 0
while True:
    oled.fill_rect(8, 32, 112, 8, 0)  # clears only the counter line
    oled.text("counter: %d" % n, 8, 32)
    oled.show()
    n += 1
    time.sleep(1)

Specifications

Item	Value	Source
Resolution	128 × 64 dots	PyPlaca component catalog
I2C address	0x3C (alternative 0x3D)	Typical datasheet values
Pin order	GND, VCC, SCL, SDA — varies by maker (variant with VCC and GND swapped)	Typical datasheet values
Driver	ssd1306.py — copy it to the board	Typical datasheet values; micropython-lib: micropython/drivers/display/ssd1306/ssd1306.py
Power supply	3.3 V in the simulator	PyPlaca component catalog — Under review: module VCC range (does it accept 5 V?)
Pull-up on SDA/SCL	there are modules with and without the resistors (a property of the part); without a pull-up I2C does not work	PyPlaca component catalog — Under review: check on the lab module
Screen color	white in the simulator	Under review: there are blue and yellow + blue modules — which one is in the lab?

Values marked "Under review" will still be checked against the parts in the lab.