Smart display module with on-board controller (serial HMI and MCU display modules)
Intelligent displays · on-module MCU or serial HMI controller, flash for images, UART command link, supply current
A smart display module puts a controller behind the panel: either a serial HMI controller that stores fonts, images and screen pages in its own flash and takes commands over a UART, or a microcontroller such as an ESP32 that runs the whole user interface and talks to the rest of the product over Wi-Fi, Bluetooth or serial ports. Ask three things first: which side runs the interface logic, how much flash and RAM the module has for graphics, and what link, voltage and current it needs.
Display modules with an on-board processor and firmware: serial (UART, RS232 or RS485) HMI displays and microcontroller display modules such as ESP32-based TFT boards. Bare TFT and character LCD modules driven over RGB, LVDS, MIPI, SPI or parallel pixel interfaces are covered on the LCD module page. LED video-wall modules, AMOLED microdisplays and complete panel PCs are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 3 sources
Nextion describes its serial HMI as a control and visualisation interface between a person and a machine. Its 3.5-inch NX4832T035 lists 480 × 320 pixels (settable to 320 × 480), 65,536 colours in 16-bit 5-6-5 format, resistive touch rated above 1 million touches, 16 MB flash to store fonts and images and 3,584 bytes of RAM for variables; a microSD socket is used only to upgrade firmware and HMI designs. [1]
GUITION's 2.8-inch ESP32-2432S028R instead uses an ESP32 module as the main controller: a dual-core MCU at up to 240 MHz with 520 KB SRAM, 448 KB ROM and 4 MB flash, integrated Wi-Fi and Bluetooth, a 240 × 320 resistive touch display, a TF card slot, a serial interface and reserved I/O, programmable in Arduino IDE, ESP-IDF, MicroPython and Mixly. [2]
Espressif's ESP32 datasheet confirms 448 KB ROM and 520 KB on-chip SRAM, Xtensa single- or dual-core LX6 processors, and CoreMark scores of 539.98 for one core and 1079.96 for two cores at 240 MHz, with full 802.11 b/g/n Wi-Fi. [3]
Editorial calculation: a full 240 × 320 frame at 16 bits per pixel is 240 × 320 × 2 = 153,600 bytes, about 29% of the ESP32's 520 KB SRAM (153,600 ÷ 532,480), so a single frame buffer fits on chip while leaving room for the application. [2][3]
Tell the supplier who writes the interface (you on the MCU, or a page design downloaded to the serial HMI), screen size and resolution, touch type, the host link, firmware update path, and expected production volume.
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Check the command link, memory and supply current
For the NX4832T035, Nextion lists a TTL 3.3 V serial port with a standard baud rate of 9600 bps and a range of 2400 to 921600 bps, an operating voltage of 4.75–7 V (5 V typical), 145 mA at 5 V and full brightness, 15 mA in sleep mode, a recommended 5 V, 500 mA supply, and a 180 nit backlight adjustable in 1% steps with average life above 30,000 hours. [1]
Its working temperature is −20 to 70 °C, storage −30 to 85 °C and working humidity 10–90% RH. In Nextion's comparison, the 5-inch 800 × 480 Basic model NX8048T050 draws 410 mA with 16 MB flash and a 48 MHz MCU, while the Intelligent model NX8048P050-011R draws 210 mA with 128 MB flash, 512 KB SRAM and a 200 MHz MCU. [1]
Editorial calculation: 145 mA × 5 V ≈ 0.73 W at full brightness and 15 mA × 5 V = 0.075 W in sleep for the 3.5-inch model. At 115200 bps with 10 bits per byte (8N1, assumed), a UART moves about 11,520 bytes per second; one raw 480 × 320 × 2-byte frame (307,200 bytes) would take about 27 seconds, which is why a serial HMI keeps images in its own flash and the host sends only short commands. [1]
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Nextion serial HMIs and a GUITION ESP32 module: controller, panel and memory
Ask each supplier for the controller, flash and RAM, supported design tools, host link and voltage levels, and the operating temperature of the complete module.
Resolution, brightness, UART speed, supply current and temperature range for a display module
Contrast ratio and viewing angle are not given for any reviewed module, and bare modules carry no ingress rating, so ask for these with the front bezel you plan to use.
3 companies list this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Shenzhen Jingcai Intelligent Co., Ltd.
Manufacturing site to be confirmed for the order
Lists ESP32, ESP32-P4 and HMI display modules, including a 2.8-inch ESP32 display module.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What is the difference between a smart display module and an LCD module?
A smart display module carries its own controller and memory: a serial HMI stores images and pages in flash (16 MB on one Nextion model) and takes UART commands, while an ESP32 module runs the interface itself. [1][2]
What baud rates does a serial HMI display use?
Nextion lists 9600 bps as standard and 2400 to 921600 bps as the range for its 3.5-inch model. [1]
How much memory does an ESP32 display module have?
The ESP32 has 520 KB SRAM and 448 KB ROM; one 2.8-inch module adds 4 MB flash. [3][2]
Sources and what still needs a direct check
Sources checked 2026-10-12. Nextion (ITEAD) and GUITION are makers publishing data for their own serial HMI and ESP32 display modules; Espressif publishes the datasheet of the ESP32 chip used on such modules.
