RN4871-I/RM128 Bluetooth Low Energy Module Data Sheet and Design Guide
Introduction
The RN4871-I/RM128 from Microchip Technology is a highly integrated, feature-rich Bluetooth Low Energy (BLE) module designed to streamline the implementation of wireless connectivity in a wide range of applications. This module combines a Bluetooth 5-compliant radio with a powerful onboard microcontroller, offering a compact and certified solution that significantly reduces development time, complexity, and cost. Targeting applications from consumer electronics and medical devices to industrial IoT sensors, the RN4871 provides a robust and reliable wireless link.
Key Features and Specifications
The core of the RN4871 module's appeal lies in its comprehensive set of features:
Bluetooth 5 Support: It supports the latest BLE 5.0 features, including 2x the speed (2Mbps PHY), 4x the range (Coded PHY with Forward Error Correction), and 8x the advertising capacity compared to Bluetooth 4.2.
Integrated Stack and Profiles: The module comes pre-loaded with Microchip's proven BLE stack and supports various GAP and GATT-based roles (Central, Peripheral, Broadcaster, Observer). It includes standard UUIDs for common services like UART Transparent, Device Information, and Battery, enabling rapid prototyping.
Simple UART Interface: The primary method of communication with a host microcontroller is through a simple ASCII-based UART command interface. This allows developers to send AT-style commands to configure the module and exchange data without deep knowledge of the BLE protocol.
Compact Form Factor: The RM128 package is extremely small, making it ideal for space-constrained designs.
Comprehensive Security: It features AES-128 encryption for secure connections, ensuring data integrity and confidentiality.
Low Power Consumption: Optimized for battery-operated devices, it offers very low power consumption in various operational modes, including deep sleep.
Design Considerations and Integration Guide
Integrating the RN4871 into a product requires attention to several key areas outlined in its design guide:
1. Power Supply: A stable and clean 3.3V power supply is critical for proper operation. The design guide emphasizes the use of appropriate decoupling capacitors close to the module's pins.
2. Antenna Design: The module includes an integrated PCB antenna. For optimal RF performance, it is crucial to follow the layout guidelines provided, particularly regarding the keep-out area beneath and around the antenna section to prevent detuning and performance degradation.
3. Host Controller Interface (HCI): The UART interface (TXD, RXD) must be connected to the host processor's UART pins. The module's Configurable I/O Pins can be repurposed for functions like waking the module from sleep or indicating connection status, adding flexibility to the design.
4. Firmware Updates: The design guide details methods for updating the module's firmware over the UART interface (DFU - Device Firmware Update), ensuring products in the field can be upgraded with new features or security patches.
5. Regulatory Certifications: The RN4871 module is pre-certified for major regulatory regions (e.g., FCC, IC, CE), which dramatically simplifies the end-product certification process. Designers must still ensure their final product complies with relevant regulations, but the module certification reduces the scope and complexity of testing.
Applications
The versatility of the RN4871 module makes it suitable for numerous applications, including:
Medical and Healthcare Devices (e.g., glucose meters, pulse oximeters, patient monitors)
Consumer Electronics (e.g., remote controls, toys, smart home devices, wearables)
Industrial IoT (IIoT) (e.g., sensor nodes, asset tracking, condition monitoring)
PC Peripherals (e.g., wireless mice, keyboards, presentation tools)
ICGOOODFIND
The RN4871-I/RM128 stands out as a premier solution for engineers seeking to add robust, certified, and high-performance Bluetooth Low Energy connectivity to their products with minimal development overhead. Its integrated protocol stack, simple UART command interface, and pre-certified status make it an excellent choice for accelerating time-to-market for a vast array of IoT and connected device applications.
Keywords: Bluetooth Low Energy, RN4871-I/RM128, UART Interface, IoT Module, BLE 5.0
