Display Technology


Tired of traditional CAN/Modbus displays? Try a ready-made STM32 display solution


By Keith Wong, technical development manager, Inelco Hunter I


n industrial automation, vehicle systems, and smart energy devices, CAN and Modbus protocols are widely used for communication between controllers, sensors, and user interface displays. These displays often rely on third-party, proprietary HMI modules that act as passive endpoints, rendering values received over CAN bus or Modbus RTU/TCP. While widely adopted, these typical HMI displays come with trade-offs: limited customisation, outdated graphics, high cost, and closed firmware. Today, powerful ready-made display solutions based on the STM32 processor ecosystem offer an affordable, flexible and modern alternative – capable of directly handling both CAN and Modbus protocols while delivering rich, interactive GUIs.


This article looks at how (and why) to replace traditional CAN/Modbus displays with STM32-based display platforms, and how developers can streamline development using STMicroelectronic’s ecosystem.


The problem with traditional CAN/ Modbus displays Basic LCD/TFT display with limited resolution Serial interface (CAN or RS-485) Predefined GUI screens (fixed layout) Firmware closed to the developer/supplier Proprietary configuration tools or scripting


The challenges of CAN/Modbus displays Minimal UI flexibility Hard to scale or customise  Firmware bug fix/upgrade highly depends on the developer/supplier


 Limited/no animations, touch interaction, or real-time responsiveness


Why use ready-made STM32 display solutions?


STM32-based displays are available from many third-party suppliers to power a wide range of HMI-ready kits with built-in display, touch interfaces and free BSP. These boards can typically directly handle both CAN (via Classic/FDCAN) and Modbus RTU/TCP (via UART or Ethernet), removing the need for a separate HMI module.


 Full protocol support (CAN & Modbus)


 Use FDCAN peripheral to receive/send CAN messages


 Use UART or Ethernet to communicate over Modbus RTU/TCP


Rich, interactive GUI


Integrated logic and UI  Replace the split architecture (controller + HMI) with a single STM32 board


 UI, logic, data parsing, and even logging handled on one device


Field upgradable & scalable


 Add SD card or Ethernet for future firmware updates


 Easily switch between UART/RS232/ RS485, CAN, or Ethernet protocols


 Port GUI projects across STM32 series with minimal code change


Cost-effective


 Reduce BOM: one MCU, one display, fewer external components


14 February 2026 Components in Electronics


Step 4: Test and validate – connect to a real or simulated CAN/Modbus master and ensure messages are received and that the GUI reflects real-time updates


Conclusion


With the support of tools like TouchGFX and STM32CubeMX, moving from rigid legacy displays to dynamic STM32-based HMIs is easier and more cost-effective than ever. Ready-made STM32 display solutions present a powerful alternative to traditional CAN and Modbus HMI displays. By combining protocol support, rich GUIs, and embedded control in one platform, developers can create highly customised and scalable interfaces for industrial and embedded systems. Inelco Hunter’s STM32 displays provide the flexibility, performance, and time-to- market advantages that today’s embedded projects demand.


www.inelcohunter.co.uk www.cieonline.co.uk


 No licence fees for graphics tools or runtime software


Replacing a typical CAN/Modbus Display: step by step


Inelco Hunter offers a range of STM32 display solutions which make product development very simple:


Step 1: Select a suitable ready-made STM32 Display from Inelco Hunter, based on: screen size, touch requirements and numbers of GPIO or interface (e.g. UART, CAN or Ethernet)


Step 2: Design GUI using TouchGFX – use TouchGFX Designer to create a graphical user interface. Add widgets for indicators, input fields, graphs, or alarms. Bind data points to variables representing CAN/ Modbus registers


Step 3: Implement CAN/Modbus protocol stack – select the appropriate stack and then parse incoming data and update GUI in real time


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