FREE SIMULATOR EXAMPLE · INTERMEDIATE

STM32: SSD1306 OLED Display (I2C)

This example drives a 128×64 SSD1306 OLED over the STM32 Blue Pill’s I2C1 bus (SCL=PB6, SDA=PB7), showing “Hello sensbench!” with a live counter that ticks every second. It is the standard display bring-up test for the F103.

Board	STM32 Blue Pill (STM32F103C8, Cortex-M3, 72 MHz)
Difficulty	intermediate
Category	displays
Libraries	Adafruit SSD1306, Adafruit GFX Library
Runs in	Sensbench browser simulator — free, no account

The exact circuit you get when you open this example — already wired, ready to run.

The sketch

// STM32 Blue Pill (F103) — SSD1306 128x64 OLED over I2C1
// Wiring: SDA -> PB7  |  SCL -> PB6  |  VCC -> 3V3  |  GND -> GND
// Requires: Adafruit SSD1306, Adafruit GFX Library

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

int counter = 0;

void setup() {
  Serial.begin(115200);
  Wire.begin();        // I2C1: SCL=PB6, SDA=PB7
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 not found!");
    while (true) delay(10);
  }
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Hello");
  display.println("sensbench!");
  display.display();
  Serial.println("OLED ready");
}

void loop() {
  counter++;
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Hello");
  display.println("sensbench!");
  display.setTextSize(1);
  display.setCursor(0, 48);
  display.print("Count: ");
  display.print(counter);
  display.display();
  Serial.print("Frame: ");
  Serial.println(counter);
  delay(1000);
}

How it works

The sketch initializes the STM32’s I2C1 as Wire (SCL=PB6, SDA=PB7 on the Blue Pill), then display.begin(SSD1306_SWITCHCAPVCC, 0x3C) starts the 128×64 panel at the standard address. The fail-fast loop prints “SSD1306 not found!” and hangs if the display does not answer — a deliberate trap so wiring errors surface immediately.

Every second the loop clears the framebuffer, redraws the header in 2x text and the incrementing counter in 1x text, then calls display.display() to blit the framebuffer to the panel in one atomic write. The Serial Monitor mirrors the frame number, so you can verify the sketch is alive even with the display out of sight.

Before you build it for real

Get the parts

Related examples

FAQ

Why does the OLED need both SSD1306 and GFX libraries?

The Adafruit SSD1306 library talks to the display controller, but it builds on Adafruit GFX for all the drawing primitives — text, pixels, shapes. The stack is the de-facto standard for SSD1306 panels and is identical on Arduino, ESP32 and STM32, so code transfers between boards without changes.

How does the counter stay visible while the text is redrawn?

The loop clears the display, redraws the static “Hello sensbench!” header, then draws the counter line and calls display.display() to push the whole framebuffer to the panel in one shot. Because the OLED holds a 1 KB framebuffer internally, there is no flicker — the panel updates atomically, not line by line.