SSD1306 i2c OLED display - not able to show images properly

Question

So I am using this 0.96" i2c yellow/blue OLED display: https://www.makerhero.com/produto/display-oled-0-96-i2c-azul-amarelo/ and an Arduino UNO clone. I have generated an image using this site https://javl.github.io/image2cpp/ and adapted the sketch below from the Adafruit official example in the Arduino IDE (ssd1306_168x64_i2c.ino)

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define OLED_RESET -1
Adafruit_SSD1306 display(OLED_RESET);
#define LOGO16_GLCD_HEIGHT 44 
#define LOGO16_GLCD_WIDTH  50 
static const unsigned char PROGMEM drawing[] =
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7e, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xf0, 0x07, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x80, 0x00, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x7c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xf0, 0x00, 0x00, 0x0f, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xc0, 0x00, 0x00, 0x03, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0x80, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0x80, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0xc0, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x01, 0xc0, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x03, 0xc0, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x03, 0xc0, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x07, 0xe0, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x03, 0xff, 0xff, 0xc0, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x01, 0xff, 0xff, 0x80, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x7f, 0xff, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x3f, 0xfc, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x1f, 0xf8, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x1f, 0xf8, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x1f, 0xf8, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x80, 0x1f, 0xf8, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x80, 0x1f, 0x7c, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc0, 0x3c, 0x1c, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x38, 0x1c, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x20, 0x06, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x40, 0x02, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x38, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x80, 0x01, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xc0, 0x03, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x78, 0x1e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x07, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void setup() {
  // put your setup code here, to run once:
  // by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  // initialize with the I2C addr 0x3D (for the 128x64)
  // init done
// Show image buffer on the display hardware.
  // Since the buffer is intialized with an Adafruit splashscreen
  // internally, this will display the splashscreen.
  display.display();
  delay(2000);
// Clear the buffer.
  display.clearDisplay();
}
void loop() {
display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);

  display.println("Botafogo");
  // put your main code here, to run repeatedly:
  display.clearDisplay();
// miniature bitmap display
  display.drawBitmap(0, 10,  drawing, 128, 50, 1);
  display.display();
  delay(2000);
}

The image I am obtaining (and have tried other images with similar results) is below, it gets trimmed in its lower part (it is supposed to be a full star, a soccer team crest).

The intended image is this one:

So what am I doing wrong or missing?

timemage · Accepted Answer · 2024-06-23T22:42:48.613

Change this line:

Adafruit_SSD1306 display(OLED_RESET);

to

Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);

The problem is not that you were sold a 32 row display labeled as 64 row. You just aren't configured for the 64 row display that you actually have. The pixels are pretty much always square on these displays. An actual 32-row display will look roughly like the top-half of your display.

Without being explicitly during construction of the display object, the Adafruit library assumes displays configured for I2C address 0x3C are 32 row and those with I2C address 0x3D are 64 row. However the configured driver I2C address and row are not strictly related. They're just guessing incorrectly for you. SSD1306 with 64 rows where the driver is configured for I2C address 0x3C are just not uncommon. Adafruit probably choose this attempted at auto-detection based on what they themselves had configured their displays for or whatever was most common in the wild at the time they wrote library.

As shown above, you can be explicit about row count, overriding their guessing. When you specify the correct row count manually will see the entire image without the unused rows between used ones that are present in both your question and own answer. And this is done without resizing the image content.

Here is a XIAO Expansion board that provides a 64 row display but configured 0x3C running. It is your code unmodified on the left and your code with only the constructor changed on the right:

Your display, like the one I've shown on the XIAO expansion board, just happens to violate Adafruit's default assumption/guess by using I2c address 0x3C and 64 rows.

I go over some of this here where someone was attempting to instruct the library to change screen resolution but not in a correct way.

SSD1306 i2c OLED display - not able to show images properly

1 Answers1