RN4020 Overview

The RN4020 is a fully-certified, Bluetooth® Version 4.1 low energy module. The small form factor surface mount module has the complete Bluetooth stack on-board and is controlled via simple ASCII commands over the UART interface. The RN4020 also includes all Bluetooth SIG profiles, as well as MLDP (Microchip Low-energy Data Profile) 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 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 Bluetooth Low Energy applications. Additional features include:

  • Fully-certified Bluetooth® version 4.1 module
  • On-board embedded Bluetooth low energy stack
  • Simple ASCII command interface over UART
  • Multiple IOs for control and status
  • Secure AES128 encryption
  • GAP, GATT, SM, L2CAP and integrated public profiles
  • Create custom services using command API
  • Data streaming with Microchip's Low Energy Data Profile (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, ADC
  • 64KB internal serial flash
  • Castellated 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 interface 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 Bluetooth® Low Energy Module Data Sheet.


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

Please visit the RN4020 MCU Interface wiki 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: www.microchip.com/wirelessfirmware

© 2020 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.