SSD1306 — 128x64 Dot Matrix OLED/PLED Controller/Driver

Overview

The SSD1306 is a single-chip CMOS OLED/PLED driver with controller manufactured by Solomon Systech. It is designed to drive 128x64 or 128x32 dot-matrix graphic organic light-emitting diode (OLED) displays.

Commonly found on 0.96" and 0.91" monochrome display modules, the SSD1306 embeds an internal 1 KB Graphic Display Data RAM (GDDRAM), an onboard charge pump circuit to generate high OLED driving voltage ( $V_{CC} \sim 9\text{ V}$ ) from a low logic supply, contrast control, and an internal oscillator.

Quick reference


Module VCC	3.3 V to 5.0 V DC (onboard LDO & charge pump)
Logic voltage ( $V_{DD}$ )	1.65 V to 3.3 V
Display resolution	128 × 64 pixels or 128 × 32 pixels
GDDRAM capacity	1 KB ( $128 \times 64$ bits)
Communication interfaces	I2C (up to 400 kHz), 4-wire / 3-wire SPI
Default I2C address	`0x3C` (SA0 = LOW) / `0x3D` (SA0 = HIGH)
Display color	Monochrome (White, Blue, Yellow, or Yellow-Blue dual color)

Pinout

Standard 4-Pin I2C Breakout Module

Pin	Name	Type	Description
1	`GND`	Power	Ground (0 V)
2	`VCC`	Power	Power supply input (+3.3 V to +5.0 V DC)
3	`SCL` / `SCK`	Digital Input	I2C Serial Clock input pin
4	`SDA`	Digital I/O	I2C Serial Data line

7-Pin SPI / I2C Breakout Module

Pin	Name	Type	Description
1	`GND`	Power	Ground (0 V)
2	`VCC`	Power	Supply voltage (+3.3 V to +5.0 V)
3	`D0` / `CLK`	Digital Input	SPI Clock line
4	`D1` / `MOSI`	Digital Input	SPI Data line (Master Out Slave In)
5	`RES` / `RST`	Digital Input	Active-LOW Hardware Reset line
6	`DC` / `A0`	Digital Input	Data / Command control pin (`LOW` = Command, `HIGH` = Data)
7	`CS`	Digital Input	Active-LOW Chip Select line

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Chip Logic Voltage	$V_{DD}$	1.65	2.8	3.3	V	Core logic supply
Display Panel Voltage	$V_{CC}$	7.0	9.0	15.0	V	Generated via internal charge pump or external
Operating Current	$I_{CC}$	—	15	25	mA	128x64 display, 50% pixels ON
Sleep Current	$I_{sleep}$	—	1	10	µA	Display OFF / Sleep mode
I2C Clock Frequency	$f_{SCL}$	0	—	400	kHz	Fast Mode
SPI Clock Cycle	$t_{cycle}$	100	—	—	ns	Max 10 MHz SPI clock
Operating Temperature	$T_{OP}$	-40	—	85	°C

Addressing & Command set

I2C Framing & Control Byte

On the I2C bus, data bytes are preceded by a Control Byte containing the $D/\bar{C}$ (Data/Command) bit:

0x00 (Command byte): Following byte is interpreted as a setup/configuration command.
0x40 (Data byte): Following byte is written directly to GDDRAM.

Key Configuration Commands

Command Hex	Description
`0xAE`	Display OFF (Sleep mode)
`0xAF`	Display ON (Normal mode)
`0x20`	Set Memory Addressing Mode (`0x00` = Horizontal, `0x01` = Vertical, `0x02` = Page)
`0x81`	Set Contrast Control (followed by contrast value `0x00`–`0xFF`)
`0x8D`	Charge Pump Setting (followed by `0x14` to enable internal charge pump)
`0xA6` / `0xA7`	Set Normal (`0xA6`) / Inverse (`0xA7`) display

Wiring

SSD1306 I2C Module	Microcontroller (Arduino Uno / ESP32)	Notes
`GND`	`GND`	Ground
`VCC`	`5V` (or `3.3V`)	Power supply
`SCL`	`SCL` (A5 on Uno, GPIO22 on ESP32)	I2C Clock
`SDA`	`SDA` (A4 on Uno, GPIO21 on ESP32)	I2C Data

Common mistakes

Forgetting to enable internal charge pump: Without sending 0x8D followed by 0x14 during initialization, the internal high-voltage display supply ( $V_{CC}$ ) remains disabled and the screen remains completely black.
I2C address mismatch: Cheap 0.96" OLED modules alternate between 0x3C (default for 128x64) and 0x3D depending on how the hardware SA0 resistor jumper is populated on the back PCB.
RAM footprint on small MCUs: Storing a full $128 \times 64$ bit monochrome frame buffer requires 1024 bytes of SRAM. On ATmega328P (2 KB SRAM), this leaves only 1 KB of RAM for remaining application code.

Notes

Monochrome OLED pixels degrade over extended continuous display of static images. Implement a screen saver or pixel-shifting routine for long-running displays.

Interface	I2C, 4-Wire SPI, 3-Wire SPI, 8-bit Parallel
Package	COG / 0.96" and 0.91" OLED Breakout Board