Description
3.5 inch display for raspberry pi Introduction
The HTM-H035A31-MCU-A01, launched by HOTHMI, is a high-performance 3.5 inch display for raspberry pi and general-purpose embedded systems. This LCD module features a resolution of 320(RGB) x 480 pixels, adopting a Normally Black panel with IPS-level full-viewing-angle technology. With a 1200:1 high contrast ratio and 69% NTSC color gamut, it delivers vivid, finely restored, and outstanding visual performance. The built-in powerful ILI9488 driver IC natively supports the efficient I-80 System 16-bit parallel bus, while also being compatible with 8-bit bus and 4-wire SPI serial interfaces, offering great flexibility and convenience for development across different hardware and software platforms.
For hardware expansion, the 3.5 inch display for raspberry pi module provides multiple configurable options, including non-touch, resistive touch, and capacitive touch with the GT911 driver IC. The PCBA also integrates an LDO voltage regulator circuit and an optimized backlight driver circuit, achieving a brightness of 400 cd/m² in non-touch configuration. Moreover, this product features excellent industrial-grade reliability, supporting a wide storage temperature range from -30℃ to +80℃ and stable operation from -20℃ to +70℃, making it an ideal choice for upgrading display interfaces in various smart devices, industrial instruments, and handheld terminals.
Core Product Highlights
- Full-viewing-angle normally black technology, eliminating visual blind spots: With advanced IPS-level normally black panel technology, the viewing directions reach U80/D80/R80/L80. This ensures that colors remain true without distortion or graying from any angle, perfectly solving the viewing angle pain points common with traditional TN panels.
- 1200:1 ultra-high contrast ratio for stunning colors: The white color performance is excellent, with a contrast ratio as high as 1200:1, combined with a 69% NTSC wide color gamut. Blacks are deep, whites are bright, and image reproduction is highly accurate, meeting the display requirements of high-end medical and automotive instruments.
- Mainstream multi-interface full compatibility for extremely flexible development: The module natively supports 4-line 8-bit serial interface, I-80 system 8-bit parallel bus, and the default I-80 system 16-bit parallel bus, providing great convenience for engineers seeking versatile 3.5 inch display for raspberry pi solutions and general-purpose MCU/FPGA development schemes.
Pin Configuration
This module adopts a standard 30-Pin 2.54mm pitch pin header interface with well-defined signal assignments and intuitive hardware connections, making it an ideal choice for building 3.5 inch display for raspberry pi prototypes and general-purpose embedded mainboards.
Core Application Scenarios
- Industrial control terminals and automation HMI interfaces
The 3.5 inch display for raspberry pi module features excellent industrial-grade durability, supporting a wide storage temperature range from -30℃ to +80℃ and stable operation from -20℃ to +70℃, having passed rigorous thermal shock and vibration resistance tests. With native support for the 16-bit parallel bus, it is ideally suited for seamless connection to the FSMC interface of industrial-grade MCUs such as STM32, GD32. It serves perfectly as the core display component for CNC machine control panels, power monitoring instruments, smart charging station terminals, and industrial assembly line HMI machine interfaces. - Smart home control centers and IoT gateways
In high-end IoT applications, this 3.5 inch display for raspberry pi module is often integrated into smart multifunctional wall switches, central air conditioning control panels, and security alarm terminals. With the optional GT911 capacitive touchscreen and paired with ESP32-S3, Espressif series chips running the LVGL graphics library, it delivers extremely smooth 16-bit/18-bit true-color multi-touch gesture UI interactions on low-power microcontroller platforms, providing a premium touchscreen experience for whole-home smart ecosystems. - Portable medical devices and automotive measurement instruments
Benefiting from the 1200:1 ultra-high contrast ratio and 69% NTSC fine color reproduction, this 3.5-inch screen can accurately and clearly present complex medical waveform data and in-vehicle sensor metrics. It is well-suited for applications such as handheld oximeters, portable ECG monitors, automotive OBD multi-function diagnostic tools, and digital instrument clusters for agricultural machinery, where display reliability is critically demanding. - Raspberry Pi full-ecosystem maker and educational research projects
Beyond its core industrial applications, this product also enjoys strong popularity in the maker education market. For advanced engineers using this module as a 3.5 inch display for raspberry pi solution, whether it involves leveraging the PIO state machine of the Raspberry Pi Pico/RP2040 to maximize the 16-bit parallel bus refresh rate at the low-level, or adopting the 4-wire SPI serial mode on Linux mainboards (Raspberry Pi 4B/5) for cross-platform embedded display driver development and Device Tree teaching, this module serves as an ideal experimental and product development carrier.
Technical Q&A of 3.5 inch display for raspberry pi
Q1: Can this 3.5 inch display for raspberry pi module be directly plugged into the 40-Pin header of a Raspberry Pi 4B or 5?
A1: No, it cannot be directly plugged in, but it can be used via wiring or compatible configuration. Some 3.5-inch screens on the market are specifically designed for Raspberry Pi mainboards with full direct-plug pin headers. This module, however, adopts an industrial-grade pin header design to accommodate the 16-bit parallel interface needs of general-purpose industrial MCUs.
If you intend to use it with a Raspberry Pi 4B/5, we recommend switching it to 4-wire SPI serial mode and using jumper wires to connect VCI, GND, CS, RS(DC), WR(SCLK), SDA(MOSI), and RESX to the corresponding hardware SPI pins on the Raspberry Pi.
If you are using a Raspberry Pi Pico microcontroller, you can use the parallel mode for perfect wiring, easily building your own 3.5 inch display for raspberry pi development project.
Q2: What are the advantages of driving this screen with an STM32 chip via the 16-bit parallel bus (8080 interface) without using a Raspberry Pi?
A2: The advantages are achieving extremely high refresh rates and very low CPU usage.
When using the FSMC or FMC hardware bus interface of an STM32 (such as the STM32F407 or STM32H7 series) to drive this ILI9488 screen, the system directly maps the screen’s frame buffer into the MCU’s memory address space. Writing pixel commands to the screen only requires a simple C language pointer assignment instruction. With the 16-bit bidirectional data bus, the data throughput is dozens of times higher than that of a standard SPI serial interface, easily achieving full-frame rendering at 60Hz or above while consuming almost no MCU main frequency computing power, making it highly suitable for running complex industrial-grade animated GUIs.
