U8x8 Fonts -

Here's an example of how you might render a U8x8 font on a microcontroller:

#include <stdint.h>
// Define the font data
const uint8_t font_data[] = 
  // Font data for character 'A'
  0b00000000, 0b00000000, 0b00000000, 0b00000000,
  0b00000000, 0b00001110, 0b00001110, 0b00001110,
  0b00000000, 0b00010001, 0b00010001, 0b00010001,
  0b00000000, 0b00001110, 0b00001110, 0b00001110,
;
// Define the rendering function
void render_font_char(uint8_t char_code, uint8_t x, uint8_t y) 
  // Load the font data for the character
  uint8_t *font_ptr = &font_data[char_code * 8];
// Render the font bitmap on the screen
  for (uint8_t i = 0; i < 8; i++) 
    uint8_t bitmap = font_ptr[i];
    for (uint8_t j = 0; j < 8; j++) 
      if (bitmap & (1 << j)) 
        // Set the pixel on the screen
        lcd_set_pixel(x + j, y + i, 1);
// Render the character 'A' on the screen
render_font_char('A', 10, 10);

Cause: You are using a U8g2 font with a U8x8 constructor or vice versa. Fix: Ensure you use u8x8.setFont(u8x8_font_...); (note the u8x8_ prefix) not u8g2.setFont(...).

The U8x8 font format is a perfect example of an elegant constraint in embedded design. By sacrificing resolution and aesthetics, it delivers unmatched speed and memory efficiency. For anyone building a text-only user interface on a tiny microcontroller—whether it’s a sensor readout, a serial terminal, or a retro-style status display—U8x8 fonts remain the pragmatic, proven choice.

In the world of embedded systems, DIY electronics, and retro computing, screen real estate is often measured in millimeters and pixels. When working with small monochrome OLEDs, LCDs, or LED matrices, a specific format of typography reigns supreme: the U8x8 font. u8x8 fonts

Some display controllers rotate data differently. If your text appears mirrored or garbled, you may need to use the setFlipMode() function. U8x8 fonts are stored in a specific byte order; if your display uses a different page addressing mode, it will look like static.

U8x8 fonts are fixed-width (monospaced) pixel fonts designed for the U8x8 text-only rendering engine (part of the U8g2 graphics library).
Unlike U8g2 fonts (proportional, variable width), U8x8 fonts treat the screen as a grid of character cells (typically 8x8 pixels per character).

This is a confusing naming scheme. Wait—doesn't u8x8 require 8 pixels high? Yes. The 1x2 means the font is rendered using two 8x8 tiles stacked vertically. The physical character is 8 pixels wide and 16 pixels high, but the library treats it as two separate 8x8 blocks. This gives you high readability but cuts your available rows in half. Here's an example of how you might render

Using these fonts is shockingly simple compared to graphics mode.

#include <Arduino.h>
#include <U8x8lib.h>
// Initialize the display (example: SSD1306 OLED over I2C)
U8X8_SSD1306_128X64_NONAME_SW_I2C u8x8(/* clock=/ SCL, / data=/ SDA, / reset=*/ U8X8_PIN_NONE);
void setup() 
u8x8.begin();
u8x8.setFont(u8x8_font_artosserif_8x8); // Select your u8x8 font Cause: You are using a U8g2 font with
// No need to clear the screen; u8x8 handles it.
u8x8.drawString(0, 0, "Hello, World!");
u8x8.setCursor(0, 2);
u8x8.print("Row 3");

void loop() {}

Notice the key functions: drawString, setCursor (using row/column, not pixels), and print.

To change the font, you literally just change the pointer passed to setFont. The library handles the rest.