LVGL + ESP32 + TFT_eSPI (ILI9341)

Minimal Working Example — Custom Display & Touch Drivers

This project demonstrates a clean and stable setup for running LVGL 9.4.0 on an ESP32 Mini1 with an ILI9341 TFT display + resistive touchscreen, using TFT_eSPI as the only SPI manager.

LVGL's built-in ILI9341/TFT_eSPI and touch drivers are intentionally not used due to:

• Unreliable SPI handling
• Impossible / incorrect touchscreen calibration
• Rotation conflicts

A custom display driver and input driver are implemented instead.

The minimal implementation is in /LVGL_example.

An implementation with WiFi and FreeRtos is also provided in /LVGL_FRTOS_WIFI (needed to setup your wifi SSID and Password)

📌 Environment

Component	Version / Notes
Board	Wemos D1 Mini ESP32
Display	ILI9341 + resistive touch
Libraries	LVGL 9.4.0, TFT_eSPI 2.5.43
IDE	Arduino IDE
Compilation Target	Wemos D1 Mini ESP32

📡 Hardware Wiring

The TFT and touch controller share the SPI bus (MISO / MOSI / SCLK).
Only CS pins differ.

ESP32 Mini1   →   TFT / Touch
-----------------------------------
19  (MISO)    →   MISO
23  (MOSI)    →   MOSI
18  (SCLK)    →   SCLK

15  (TFT_CS)  →   TFT CS
2   (TFT_DC)  →   TFT DC
RST (shared)  →   TFT_RST (-1)

17  (TOUCH_CS) → Touch CS

➡️ No pull-ups or pull-downs required.

⚙️ TFT_eSPI Configuration

Edit:

Documents/Arduino/libraries/TFT_eSPI/User_Setup.h

Use these settings:

#define ILI9341_DRIVER

#define TFT_MISO 19
#define TFT_MOSI 23
#define TFT_SCLK 18

#define TFT_CS   15
#define TFT_DC    2
#define TFT_RST  -1   // uses ESP32 reset

#define TOUCH_CS 17

#define SPI_FREQUENCY       27000000
#define SPI_READ_FREQUENCY  20000000
#define SPI_TOUCH_FREQUENCY  2500000

⚙️ LVGL Configuration

1. Copy lvgl template configuration file from:

C:/Users/USER_NAME/Documents/Arduino/libraries/lvgl/lv_conf_template.h

to: (renaming it)

C:/Users/USER_NAME/Documents/Arduino/libraries/lv_conf.h

2. Enable with:

   #if 1
   

No additional changes are required except disabling LVGL’s incorrect touch rotation logic.

🛠 Required Patch: Disable LVGL Touch Rotation

TFT_eSPI already provides correct coordinates with rotation applied.
LVGL applies additional transformations, causing misaligned touch input.
These must be removed.

Edit:

C:/Users/USER_NAME/Documents/Arduino/libraries/lvgl/src/indev/lv_indev.c

Comment out the block around lines 693–703:

// if(disp->rotation == LV_DISPLAY_ROTATION_180 || disp->rotation == LV_DISPLAY_ROTATION_270) {
//     data->point.x = disp->hor_res - data->point.x - 1;
//     data->point.y = disp->ver_res - data->point.y - 1;
// }
// if(disp->rotation == LV_DISPLAY_ROTATION_90 || disp->rotation == LV_DISPLAY_ROTATION_270) {
//     int32_t tmp = data->point.y;
//     data->point.y = data->point.x;
//     data->point.x = disp->ver_res - tmp - 1;
// }

After this fix:

• Touchscreen calibration works
• Coordinates match LVGL rotation
• No flipping / mirroring issues

✅ Summary

This project provides:

• Stable LVGL rendering on ESP32
• Accurate, rotation-correct touchscreen input
• A single, clean TFT_eSPI instance for both display and touch
• No dependency on LVGL’s broken internal drivers