03.08.2026

Building a Dual-MCU System Using Ai-Thinker BW20 Modules

BW40 Project: A Dual-MCU Embedded System Using Ai-Thinker BW20

The BW40 Project is a work-in-progress embedded system built around the Ai-Thinker BW20 () platform. The goal of this project is to create a dual-MCU architecture capable of handling multiple wireless technologies, peripherals, and user interface operations simultaneously.

Instead of relying on a single microcontroller, the BW40 design uses two BW20 modules working together. This architecture allows better task distribution, improved performance, and a more flexible firmware platform for future expansion.

Prototype Preview

Below are early prototype builds of the BW40 system currently under development. These prototypes are used to test firmware features, hardware integrations, and communication between the dual microcontroller system.

Why a Dual-MCU Architecture?

As embedded systems grow more complex, a single microcontroller often struggles to handle multiple real-time tasks such as wireless operations, graphical interfaces, data logging, and sensor processing.

To address this limitation, the BW40 platform distributes workloads across two BW20 processors.

Main MCU – Handles the graphical interface, menu system, and user interaction.
Secondary MCU – Manages peripherals, sensors, and external modules.
UART Communication – Both modules communicate using a custom command protocol.

This architecture allows the system to remain responsive even when multiple features are running simultaneously.

User Interface and Control

The BW40 prototype currently uses a small SPI display driven by a custom interface built with the LVGL graphics library. The interface provides a simple grid-style navigation system that allows users to switch between different features quickly.

Some of the modules currently visible in the interface include:

WiFi
Bluetooth (BLE)
NRF wireless module
Infrared tools
File browser
GPS integration
NFC support

Navigation is handled through physical buttons connected through the hardware interface, allowing the device to operate as a portable embedded tool.

Hardware Platform

The project is built around the Ai-Thinker BW20 module, which is based on the Realtek RTL8720DN chipset.

Key capabilities of the BW20 platform include:

Dual-band WiFi support (2.4GHz and 5GHz)
Bluetooth Low Energy
High-performance MCU cores
Flexible GPIO and peripheral interfaces
RTOS firmware support

These features make it a strong platform for building compact wireless development tools and experimental embedded systems.

Peripheral Support

The BW40 system is designed to support multiple peripherals that extend its capabilities beyond a standard microcontroller board.

SPI display modules
MicroSD storage for logging
GPS modules for location data
NRF wireless modules
I2C expanders for button input
UART devices for external communication

This flexible hardware design allows the platform to evolve into a versatile embedded experimentation environment.

Firmware Development

Firmware for the BW40 project is currently developed using the Realtek Ameba SDK. The firmware focuses on modular architecture, efficient task scheduling, and reliable communication between the two processors.

Current development areas include:

Dual-MCU communication protocol
Peripheral integration
Wireless feature testing
Graphical interface improvements
Data logging and storage

Current Status

The BW40 system is still in the prototype and experimentation phase. Hardware revisions and firmware improvements are continuously being tested as new features are added.

These early builds help validate the architecture and ensure that the system can scale to support more advanced capabilities in the future.

Looking Ahead

Future development plans for the BW40 platform include expanding wireless tools, improving the graphical interface, and integrating additional sensors and modules.

The long-term vision is to create a powerful yet compact embedded system that can serve as a flexible platform for experimentation, firmware development, and wireless technology exploration.

This project is currently under active development. More updates and progress will be shared as the BW40 platform continues to evolve.