RN4020 Overview

The RN4020 is a fully-certified, Bluetooth® Version 4.1 Low Energy (BLE) module. The small form-factor surface mount module has the complete Bluetooth stack on-board and is controlled via simple ASCII commands over the Universal Asynchronous Receiver Transmitter (UART) interface. The RN4020 also includes all Bluetooth Special Interest Group (SIG) profiles, as well as Microchip Low-energy Data Profile (MLDP) for custom data. The scripting feature can be used to enable standalone operation without a host MCU or processor. The RN4020 can be remote-controlled by another module over a secure connection and can be updated via the UART interface or over-the-air.

Click image to enlarge.
RN4020 Top View

The RN4020 has a built-in high-performance Printed Circuit Board (PCB) antenna optimally tuned for long range, typically over 100 meters. Its compact size enables ease of integration in size-constrained applications. The RN4020 can be used with any low-cost microcontroller for intelligent BLE applications. Additional features include:

  • Fully-certified Bluetooth version 4.1 module
  • On-board embedded BLE stack
  • Simple ASCII command interface over UART
  • Multiple IOs for control and status
  • Secure AES128 encryption
  • Generic Access Profile (GAP), Generic Attribute Profile (GATT), SM, L2CAP, and integrated public profiles
  • Create custom services using command Application Programming Interface (API)
  • Data streaming with MLDP
  • Scripting for standalone module operation with analog and digital data collection
  • 7 dBm transit power for 100 meter+ range
  • Field-upgradeable via the UART interface or over-the-air
  • Software configurable role as peripheral or central, client, or server
  • Compact form factor 11.5 x 19.5 x 2.5 mm
  • Low power modes
  • UART interface, GPIO, Analog-to-Digital Converter (ADC)
  • 64KB internal serial flash
  • Castellated Signal Measurement Timer (SMT) pads for easy and reliable PCB mounting
  • Environmentally friendly, RoHS compliant
  • Certifications: FCC, IC, CE, QDID

Block Diagram


MCU Interface

The picture below illustrates the basic interfac between PIC® microcontroller and the RN4020 module. The minimum interface consists of UART TX/RX and WAKE_HW/WAKE_SW lines. This enables the microcontroller to communicate with the RN4020 module using ASCII command API. The command API can be found in section 6.0 of the RN4020 BLE Module Datasheet.


If the RN4020 is operated in a Hostless mode (without a microcontroller), set the UART_RX pin to high via a 10 K resistor to reduce power consumption in Deep Sleep mode.

Please visit the RN4020 MCU Interface DeveloperHelp page for a detailed description of the MCU interface.

Supported Services

The RN4020 firmware supports the following built-in public services which are enabled and serviced via Command API. In addition, this module also gives you the ability to create your own private services.

  • Device Information
  • Battery
  • Heart Rate
  • Health Thermometer
  • Glucose
  • Blood Pressure
  • Running Speed Cadence
  • Cycling Speed Cadence
  • Current Time
  • Next DST Change
  • Reference Time Update
  • Link Loss
  • Immediate Alert
  • TX Power
  • Alert Notification
  • Phone Alert Status
  • Scan Parameters

For the latest list of services refer to the firmware version on the RN4020 web page.


The following core documentation is required to work with the module:

Application Notes and various demos can be found at the product's home page at www.microchip.com/rn4020.

Module Firmware Revisions

For the latest firmware details and corresponding part numbers, please visit: the wireless firmware page.

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