07 Display

Link to Source: samples/07_display_cfb

Overview

This sample demonstrates the use of Zephyr’s Character Frame Buffer (CFB) subsystem to display text on a monochrome display.

This sample is useful for:

  • Understanding the Character Frame Buffer subsystem

  • Learning to write text to displays

  • Working with different font sizes

  • Display control and initialization

Key Features:

  • Multiple font support

  • Text positioning on display

  • Kerning control for character spacing

  • Display parameter querying

Requirements

  • A board with CFB-supporting display (e.g., reel_board@2)

Supported Boards:

  • reel_board@2 (has onboard passive display)

Building

host:~$ west build -b reel_board@2 samples/07_display_cfb -p
host:~$ west flash

Sample Output

*** Booting Zephyr OS build v4.3.0 ***
Initialized display@0
idx: 0, font width 10, font height 16
idx: 1, font width 15, font height 24
x_res 128, y_res 296, ppt 2, rows 32, cols 64

Display Output

The display will show:

  • “Zephyr Workshop”

  • “CFB Demo”

  • “<name>” (placeholder for your name)

Customization

Edit samples/07_display_cfb/src/main.c to change the displayed text:

cfb_print(dev, "Your Text", x_position, y_position);

Resources