ONX3248G035
A 3.5 inch OpenNextion ESP32-S3 development board with a larger 320x480 display for richer dashboards and interactive applications.
Wiki updated on 2026-06-16
Overview
Key Features
ESP32-S3 Xtensa 32-bit LX7 dual-core processor up to 240 MHz, with 8 MB PSRAM and 16 MB Flash.
3.5-inch capacitive touch LCD with ST7796 panel driver and CST826 touch controller.
2.4 GHz Wi-Fi and Bluetooth 5 LE, onboard antenna, and reserved external antenna connector.
Camera, digital microphone, speaker, MicroSD, Grove I2C/UART, RTC, battery, and GPIO expansion interfaces.
USB-C supports power supply, firmware flashing, log printing, and automatic download mode.
Preview
Specifications
Model Name
ONX3248G035
Size
3.5 inch
Resolution
320x480
Color
262K
Brightness
300 nit
Touch Type
Capacitive
MCU
ESP32-S3R8
Flash
16 MB
PSRAM
8 MB
Panel Driver
ST7796
Touch Driver
CST826
Operating Voltage
DC 5V-1A
Working Temperature
-20~70 C
Storage Temperature
-30~80 C
Weight
Net 61g / Gross 115g
Interfaces
1.USB_UART
USB-CUSB to UART for firmware flashing, log printing, and power supply.
2.RTC BAT
MX1.25-2PRTC battery interface, 3V.
3.BOOT Button
Hold BOOT and press RESET once to enter firmware download mode.
4.RST Button
Reset button.
5.I2C
PH2.0-4P (Grove)Grove-standard I2C pinout.
6.UART1
PH2.0-4P (Grove)Grove-standard UART pinout.
7.External Antenna Connector
IPEX-1Can switch to an external antenna by desoldering a resistor.
8.Antenna
On-board antenna.
9.MIC_PDM
FPC-4P 0.5mm pitchDigital microphone interface.
10.GPIOs
FPC-24P 0.5mm pitchBreaks out 5V, 3.3V, GND, and 14 IO pins.
11.CAMERA
FPC-24P 0.5mm pitchSupports mainstream cameras such as OV2640 and OV5640.
12.SD
MicroSD slot.
13.SPK
MX1.25-2PSpeaker interface, supports speakers up to 2W.
14.UART0
XH2.54-4PSerial communication, firmware flashing, log printing, and power supply.
15.Power Switch
Power control switch.
16.Power Indicator
Power indicator. ON: Red; OFF: Off.
17.Charging Indicator
Charging indicator. No battery connected: Off; charging: Red; fully charged: Off.
18.BAT
MX1.25-2PLithium battery interface, 3.7V.
Product Dimensions
Pin Description
UART0
TXD(IO43), RXD(IO44)
Multiplexed with USB_UART TXD/RXD.
UART1
TXD(IO13), RXD(IO12)
I2C
SCL(IO7), SDA(IO8)
MIC_PDM
CLK(IO19), DATA(IO20)
CAMERA
VSYNC(IO17), PWDN(EXIO3), HREF(IO18), XCLK(IO38), PCLK(IO41), D0-D7(IO45/47/48/46/42/40/39/21)
24pin GPIOs
IO12, IO13, IO20, IO19, IO17, IO18, IO21, IO38, IO39, IO40, IO42, IO45, IO47, IO48
Multiplexed with UART1, MIC_PDM, and CAMERA interfaces.
SPK
I2S_CTRL(EXIO0), I2S_LRCLK(IO16), I2S_BCLK(IO14), I2S_SDIN(IO15)
SD
SDCS(EXIO6), MISO(IO9), MOSI(IO10), SCLK(IO11)
RTC
RTC_INT(EXIO1), I2C_SCL(IO7), I2C_SDA(IO8)
Backlight
LCD_BL(IO6)
Resources
FAQ
Buttons
The board includes RESET, BOOT, and POWER keys. Hold BOOT while pressing RESET to enter firmware download mode.
Waterproofing
The product itself is not waterproof; a custom waterproof enclosure is required.
External antenna
An external antenna connector is reserved, and the board can be switched to an external antenna by desoldering a resistor.
Microphone accessory
The compatible accessory is the Nextion Dual MIC Board, which includes two digital microphones.
Speaker power
The external speaker interface supports up to 2W.
Download mode
USB-C supports automatic download mode; UART0 does not.
UART multiplexing
USB_UART and UART0 TXD/RXD signals are multiplexed and cannot be used at the same time.
GPIO multiplexing
GPIO pins are multiplexed with MIC_PDM, UART1, and CAMERA interfaces and cannot be used simultaneously.
Compatibility
This development board can run OpenNextion firmware examples and works with supported OpenNextion accessories.