Nextion NX4832K035 3.5“ HMI TFT LCD TOUCH Display module

Pinout & Connection Guide

The module uses a simple 4-pin, 2.54mm pitch header for all communication and power. The pinout is clearly marked on the back of the PCB.

Pin Definitions

Wiring Diagrams

Arduino Uno / Mega (5V logic):

NX4832K035              →    Arduino Uno
──────────────────────────────────────────────
VCC                     →    5V
TXD                     →    RX (Pin 0)
RXD                     →    TX (Pin 1)
GND                     →    GND

ESP32 (3.3V logic):

NX4832K035              →    ESP32
──────────────────────────────────────────────
VCC                     →    External 5V Supply (not from ESP32)
TXD                     →    GPIO16 (RX2)
RXD                     →    GPIO17 (TX2)
GND                     →    GND

Note: Power the Nextion from a stable external 5V supply capable of delivering 500mA. The ESP32’s 3.3V pin cannot power the display .

Raspberry Pi:

NX4832K035              →    Raspberry Pi
──────────────────────────────────────────────
VCC                     →    Pin 2 (5V) or external 5V supply
TXD                     →    Pin 10 (RXD / GPIO15)
RXD                     →    Pin 8 (TXD / GPIO14)
GND                     →    Pin 6 (GND)

USB-to-TTL Adapter (for PC debugging):

NX4832K035              →    USB-to-TTL Adapter
──────────────────────────────────────────────
VCC                     →    5V
TXD                     →    RXD
RXD                     →    TXD
GND                     →    GND

Development & Usage Guide

1. Nextion Editor Software

Design your HMI interface using the free Nextion Editor software, available for download from the official Nextion website . The software features:

• Drag-and-Drop Components: 25+ built-in components including buttons, text boxes, sliders, progress bars, gauges, timers, and more

• Font Creator: Generate custom fonts with specific encoding (UTF-8 support for international characters)

• WYSIWYG Interface: See exactly how your GUI will look while you design it

• Free Simulator: Debug your HMI project without hardware—test interactions and commands in real-time

• Text-based Instruction Set: Simple ASCII commands for programming interactions

2. Creating Your First HMI Project

Basic Workflow:

1. Launch Nextion Editor and click “New”

2. Select “Enhanced” as the series and choose “NX4832K035” as the model

3. Drag components from the toolbox onto the page canvas

4. Configure component properties (colors, text, size, position, etc.)

5. For interactive components, enable “Send Component ID” in the Event pane to allow your host MCU to detect touch events

6. Set communication baud rate—add bauds=115200 (or your desired rate) to the Preinitialize Event of the first page

7. Press F8 to compile the project and generate a .tft firmware file

3. Uploading Firmware to the Display

Method 1: microSD Card (Recommended)

1. Format a microSD card as FAT32 (maximum 32GB)

2. Copy the compiled .tft file to the root directory of the SD card

3. Ensure the card contains only one .tft file

4. Power off the Nextion display

5. Insert the microSD card into the display’s slot

6. Power on the display—firmware uploads automatically

7. After “Update Successed!” message appears, power off

8. Remove the microSD card before powering on again

Method 2: USB-to-TTL (Alternative)

• Upload via serial using the 4-pin interface, though SD card method is faster and more reliable

4. Power Supply Considerations

Critical Power Requirements:

• The NX4832K035 requires a stable 5V DC power supply capable of delivering at least 500mA

• Operating current is 145mA at 100% brightness, with higher peaks during startup

• Do not power the display from your microcontroller’s 3.3V pin

• The power test board included in the package allows you to verify your power supply can meet the requirements

5. Host MCU Communication (Arduino Example)

Once your GUI is loaded, control the display from your microcontroller using simple print statements. Important: Every command sent to the Nextion must end with three bytes of 0xFF (the command terminator) .

// Nextion NX4832K035 Basic Control Example

void setup() {
  // Initialize Serial (for Nextion) at 115200 baud
  Serial.begin(115200);
  
  // Wait for display to boot
  delay(3000);
}

void loop() {
  // Example 1: Update text component named "t0"
  Serial.print("t0.txt=\"Hello World\"");
  Serial.write(0xFF); Serial.write(0xFF); Serial.write(0xFF);
  
  delay(2000);
  
  // Example 2: Update number component named "n0"
  static int counter = 0;
  counter++;
  Serial.print("n0.val=");
  Serial.print(counter);
  Serial.write(0xFF); Serial.write(0xFF); Serial.write(0xFF);
  
  delay(1000);
}

6. Using the Iteadlib Arduino Library

The ITEADLIB_Arduino_Nextion library simplifies communication by handling the 0xFF terminators automatically.

Installation:

1. Download the library ZIP from GitHub

2. In Arduino IDE: Sketch → Include Library → Add .ZIP Library

Basic Library Example:

#include "Nextion.h"

// Declare components matching your HMI design
NexText t0 = NexText(0, 1, "t0");
NexNumber n0 = NexNumber(0, 2, "n0");

void setup() {
  nexInit();  // Initializes Serial at 115200 baud
}

void loop() {
  t0.setText("Hello");  // Update text component
  n0.setValue(42);      // Update number component
  delay(1000);
}

7. ESP32 Setup Notes

When using the ESP32, configure the library for hardware Serial2:

In NexConfig.h, modify:

#define nexSerial Serial2

Additionally, comment out #include <SoftwareSerial.h> and the NexUpload files as SoftwareSerial is incompatible with the ESP32.

8. RTC Battery Installation

The Enhanced series includes a built-in Real-Time Clock. To keep time when main power is off:

• Install a CR1220 lithium battery in the battery socket on the back of the display

• The battery does NOT power the display—it only maintains RTC operation

9. GPIO Usage

The NX4832K035 provides 8 digital GPIO pins (IO0-IO7) that can be used as:

• Digital inputs: Read external sensor states

• Digital outputs: Control external devices (limit current to 1mA recommended)

• PWM outputs: IO4-IO7 support PWM for dimming LEDs or controlling servos

These GPIOs can be controlled directly from the Nextion Editor using component events, without involving your host MCU.