void LCD_DrawImage(uint16_t x, uint16_t y, uint16_t w, uint16_t h, const uint16_t *data) // Step 1: Set column address register (0x2A) LCD_WriteReg(0x2A, x); // Start column LCD_WriteReg(0x2A, x + w - 1); // End column // Step 2: Set row address register (0x2B) LCD_WriteReg(0x2B, y); // Start row LCD_WriteReg(0x2B, y + h - 1); // End row
// RGB565, 50x50 pixels, little-endian const unsigned short icon_data[2500] = 0xF800, 0xF800, 0xE800, ... ; Now, how does this work with registers on an actual MCU? Here is a typical ARM Cortex-M function that sends image data to the LCD via SPI: image2lcd register code work
Introduction In the world of embedded systems, displaying a crisp image on a small LCD screen is a deceptively complex task. Microcontrollers (MCUs) like the STM32, Arduino, or ESP32 do not natively understand BMP, JPEG, or PNG files. Instead, they communicate with display drivers (such as the ILI9341, SSD1306, or ST7789) through a series of hardware registers. Microcontrollers (MCUs) like the STM32, Arduino, or ESP32
Example:
static uint16_t framebuffer[320*240]; // Back buffer // Load initial splash from Image2LCD memcpy(framebuffer, splash_image, sizeof(splash_image)); // Modify some pixels framebuffer[100] = 0xFFFF; // white pixel // Send entire buffer to LCD via data register LCD_WriteCmd(0x2C); for (int i=0; i<320*240; i++) LCD_WriteData(framebuffer[i]); Consider an ESP32-based weather station with a 240x240 ST7789 display. By understanding how the tool generates its output,
By understanding how the tool generates its output, how to map that output to an LCD’s command set (especially register 0x2C ), and how to optimize for DMA or double buffering, you unlock professional-grade display performance on even modest microcontrollers.