In this guide, you’ll learn how to use the 0.96 inch SSD1306 OLED display with an ESP32 or ESP8266 using MicroPython firmware. As an example, we’ll show you how to display a simple ‘Hello, World!’ message. Later, we’ll also show you how to use other useful functions to interact with the OLED display.
You might also like reading our dedicated guides for ESP with OLED display using Arduino IDE:
To follow this tutorial you need MicroPython firmware installed in your ESP32 or ESP8266 boards. You also need an IDE to write and upload the code to your board. We suggest using Thonny IDE or uPyCraft IDE:
- Thonny IDE:
- uPyCraft IDE:
- Getting Started with uPyCraft IDE
- Install uPyCraft IDE (Windows, Mac OS X, Linux)
- Flash/Upload MicroPython Firmware to ESP32 and ESP8266
Learn more about MicroPython: MicroPython Programming with ESP32 and ESP8266 eBook
Introducing the OLED display
In this guide we’ll use the 0.96 inch SSD1306 OLED display that is 128×64 pixels and uses I2C communication protocol.
For the I2C OLED display, these are the connections you need to make:
|SCL||GPIO 22||GPIO 5 (D1)|
|SDA||GPIO 21||GPIO 4 (D2)|
Here’s a list of parts you need for this project:
You can use the preceding links or go directly to MakerAdvisor.com/tools to find all the parts for your projects at the best price!
Schematic – ESP32
Follow the next schematic diagram if you’re using an ESP32 board:
Recommended reading: ESP32 Pinout Reference Guide
Schematic – ESP8266
Follow the next schematic diagram if you’re using an ESP8266 board:
Recommended reading: ESP8266 Pinout Reference Guide
SSD1306 OLED Library
The library to write to the OLED display isn’t part of the standard MicroPython library by default. So, you need to upload the library to your ESP32/ESP8266 board.
#MicroPython SSD1306 OLED driver, I2C and SPI interfaces created by Adafruit import time import framebuf # register definitions SET_CONTRAST = const(0x81) SET_ENTIRE_ON = const(0xa4) SET_NORM_INV = const(0xa6) SET_DISP = const(0xae) SET_MEM_ADDR = const(0x20) SET_COL_ADDR = const(0x21) SET_PAGE_ADDR = const(0x22) SET_DISP_START_LINE = const(0x40) SET_SEG_REMAP = const(0xa0) SET_MUX_RATIO = const(0xa8) SET_COM_OUT_DIR = const(0xc0) SET_DISP_OFFSET = const(0xd3) SET_COM_PIN_CFG = const(0xda) SET_DISP_CLK_DIV = const(0xd5) SET_PRECHARGE = const(0xd9) SET_VCOM_DESEL = const(0xdb) SET_CHARGE_PUMP = const(0x8d) class SSD1306: def __init__(self, width, height, external_vcc): self.width = width self.height = height self.external_vcc = external_vcc self.pages = self.height // 8 # Note the subclass must initialize self.framebuf to a framebuffer. # This is necessary because the underlying data buffer is different # between I2C and SPI implementations (I2C needs an extra byte). self.poweron() self.init_display() def init_display(self): for cmd in ( SET_DISP | 0x00, # off # address setting SET_MEM_ADDR, 0x00, # horizontal # resolution and layout SET_DISP_START_LINE | 0x00, SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0 SET_MUX_RATIO, self.height - 1, SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0 SET_DISP_OFFSET, 0x00, SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12, # timing and driving scheme SET_DISP_CLK_DIV, 0x80, SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1, SET_VCOM_DESEL, 0x30, # 0.83*Vcc # display SET_CONTRAST, 0xff, # maximum SET_ENTIRE_ON, # output follows RAM contents SET_NORM_INV, # not inverted # charge pump SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14, SET_DISP | 0x01): # on self.write_cmd(cmd) self.fill(0) self.show() def poweroff(self): self.write_cmd(SET_DISP | 0x00) def contrast(self, contrast): self.write_cmd(SET_CONTRAST) self.write_cmd(contrast) def invert(self, invert): self.write_cmd(SET_NORM_INV | (invert & 1)) def show(self): x0 = 0 x1 = self.width - 1 if self.width == 64: # displays with width of 64 pixels are shifted by 32 x0 += 32 x1 += 32 self.write_cmd(SET_COL_ADDR) self.write_cmd(x0) self.write_cmd(x1) self.write_cmd(SET_PAGE_ADDR) self.write_cmd(0) self.write_cmd(self.pages - 1) self.write_framebuf() def fill(self, col): self.framebuf.fill(col) def pixel(self, x, y, col): self.framebuf.pixel(x, y, col) def scroll(self, dx, dy): self.framebuf.scroll(dx, dy) def text(self, string, x, y, col=1): self.framebuf.text(string, x, y, col) class SSD1306_I2C(SSD1306): def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False): self.i2c = i2c self.addr = addr self.temp = bytearray(2) # Add an extra byte to the data buffer to hold an I2C data/command byte # to use hardware-compatible I2C transactions. A memoryview of the # buffer is used to mask this byte from the framebuffer operations # (without a major memory hit as memoryview doesn't copy to a separate # buffer). self.buffer = bytearray(((height // 8) * width) + 1) self.buffer = 0x40 # Set first byte of data buffer to Co=0, D/C=1 self.framebuf = framebuf.FrameBuffer1(memoryview(self.buffer)[1:], width, height) super().__init__(width, height, external_vcc) def write_cmd(self, cmd): self.temp = 0x80 # Co=1, D/C#=0 self.temp = cmd self.i2c.writeto(self.addr, self.temp) def write_framebuf(self): # Blast out the frame buffer using a single I2C transaction to support # hardware I2C interfaces. self.i2c.writeto(self.addr, self.buffer) def poweron(self): pass class SSD1306_SPI(SSD1306): def __init__(self, width, height, spi, dc, res, cs, external_vcc=False): self.rate = 10 * 1024 * 1024 dc.init(dc.OUT, value=0) res.init(res.OUT, value=0) cs.init(cs.OUT, value=1) self.spi = spi self.dc = dc self.res = res self.cs = cs self.buffer = bytearray((height // 8) * width) self.framebuf = framebuf.FrameBuffer1(self.buffer, width, height) super().__init__(width, height, external_vcc) def write_cmd(self, cmd): self.spi.init(baudrate=self.rate, polarity=0, phase=0) self.cs.high() self.dc.low() self.cs.low() self.spi.write(bytearray([cmd])) self.cs.high() def write_framebuf(self): self.spi.init(baudrate=self.rate, polarity=0, phase=0) self.cs.high() self.dc.high() self.cs.low() self.spi.write(self.buffer) self.cs.high() def poweron(self): self.res.high() time.sleep_ms(1) self.res.low() time.sleep_ms(10) self.res.high()
Follow the next set of instructions for the IDE you’re using:
- A. Upload OLED library with uPyCraft IDE
- B. Upload OLED library with Thonny IDE
A. Upload OLED library with uPyCraft IDE
This section shows how to upload a library using uPyCraft IDE. If you’re using Thonny IDE, read the next section.
1. Create a new file by pressing the New File button.
2. Copy the OLED library code into that file. The OLED library code can be found here.
Note: the SSD1306 OLED display library was built by Adafruit and will no longer
be updated. At the moment, it works fine. However, we’ll update this guide if we
find a similar library that works as well as this one.
3. After copying the code, save the file by pressing the Save button.
4. Call this new file “ssd1306.py” and press ok.
5. Click the Download and Run button.
The file should be saved on the device folder with the name “ssd1306.py” as
highlighted in the following figure.
Now, you can use the library functionalities in your code by importing the library.
B. Upload OLED library with Thonny IDE
If you’re using Thonny IDE, follow the next steps:
1. Create a new file in Thonny IDE and copy the library code. The OLED library code can be found here.
2. Go to File > Save as and select MicroPython device.
3. Name the file ssd1306.py and click OK to save the file on the ESP Filesystem.
And that’s it. The library was uploaded to your board. Now, you can use the library functionalities in your code by importing the library.
After uploading the library to the ESP32 or ESP8266, copy the following code to the
main.py file. It simply prints the ‘Hello, World!‘ message three times in the display.
# Complete project details at https://RandomNerdTutorials.com from machine import Pin, SoftI2C import ssd1306 from time import sleep # ESP32 Pin assignment i2c = SoftI2C(scl=Pin(22), sda=Pin(21)) # ESP8266 Pin assignment #i2c = SoftI2C(scl=Pin(5), sda=Pin(4)) oled_width = 128 oled_height = 64 oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c) oled.text('Hello, World 1!', 0, 0) oled.text('Hello, World 2!', 0, 10) oled.text('Hello, World 3!', 0, 20) oled.show()
How the Code Works
Start by importing the necessary modules to interact with the GPIOs and send data to the OLED via I2C communication. You need to import the Pin and SoftI2C classes from the machine module.
from machine import Pin, SoftI2C
You also need to import the OLED library that you previously uploaded to the board as ssd1306.py file.
The ESP32 default I2C pins are GPIO 22 (SCL) and GPIO 21 (SDA). The ESP8266 default I2C pins are GPIO 5 (SLC) and GPIO 4 (SDA).
Use the following line if you’re using an ESP32 board:
# ESP32 Pin assignment i2c = SoftI2C(scl=Pin(22), sda=Pin(21))
Comment the previous line and uncomment the following if you’re using an ESP8266 board:
#ESP8266 Pin assignment i2c = SoftI2C(scl=Pin(5), sda=Pin(4))
Define the OLED width and height on the following variables:
oled_width = 128 oled_height = 64
After that, create an SSD1306_I2C object called oled. This object accepts the OLED width, height, and the I2C pins you’ve defined earlier.
oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)
After initializing the OLED display, you just need to use the text() function on the oled object to write text. After the text() function, you need to call the show() method to update the OLED.
oled.text('Hello, World 1!', 0, 0) oled.text('Hello, World 2!', 0, 10) oled.text('Hello, World 3!', 0, 20) oled.show()
The text() method accepts the following arguments (in this order):
- Message: must be of type String
- X position: where the text starts
- Y position: where the text is displayed vertically
- Text color: it can be either black or white. The default color is white and this parameter is optional.
- 0 = black
- 1 = white
For example, the following line writes the ‘Hello, World 1!’ message in white color. The text starts on x = 0 and y = 0.
oled.text('Hello, World 1!', 0, 0)
The next line of code writes the text on the next line (y =10).
oled.text('Hello, World 2!', 0, 10)
Finally, for the changes to take effect, use the show() method on the oled object.
Upload the code to your board. Your OLED display should look as follows:
Other OLED functions
The library provides other methods to interact with the OLED display.
Fill the screen
To fill the entire screen with white, use the fill() function as follows:
To clear the screen use the fill() method as pass 0 as argument. (Sets all pixels to black):
Draw a pixel
To draw a pixel, use the pixel() method, followed by the show() method. The pixel() method accepts the following arguments:
- X coordinate: pixel location horizontally
- Y coordinate: pixel location vertically
- Pixel color: can be black or white
- 0 = black
- 1 = white
For example, to draw a white pixel on the top left corner:
oled.pixel(0, 0, 1) oled.show()
You can also invert the OLED colors: white with black and vice versa, using the invert() method:
To get back to the original colors, use:
Displaying data from sensors
The text() function only accepts variables of type String as a message. Sensor readings are usually stored in int or float variables.
If you want to display sensor readings and they are stored in int or float variables, they should be converted to a String. To convert the data to a string you can use the str() function:
temperature = 12.34 temperature_string = str(temperature)
Then, you can display the temperature_string variable on the OLED using the text() and show() methods:
oled.text(temperature_string, 0, 0) oled.show()
This quick guide showed you how to use the OLED basic functionalities: write text and draw pixels with the ESP32 and ESP8266 using MicroPython. Now, you can use the OLED in your own projects to display messages, or sensor readings.
We have other MicroPython tutorials that you might also like:
- MicroPython: ESP32/ESP8266 with DHT11/DHT22
- MicroPython: ESP32/ESP8266 with DHT11/DHT22 Web Server
- MicroPython: WS2812B Addressable RGB LEDs with ESP32 and ESP8266
If you want to learn more about programming the ESP32 and ESP8266 boards with MicroPython, take a look our eBook: MicroPython Programming with ESP32 and ESP8266.