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onsemi RSL15 Bluetooth® 5.2 Secure Wireless MCU

Ultra-low power secure Arm® Cortex®-M33 processor-based BLE 5.2 wireless MCU

RSL15 is an ultra-low power secure Arm® Cortex®-M33 processor-based Bluetooth Low Energy 5.2 wireless MCU designed for connected smart devices in industrial and medical applications. With built-in power management, a wide supply voltage range, flexible GPIO and clocking scheme and an extensive set of peripherals, the RSL15 offers maximum design flexibility for high performance and ultra-low-power applications. The RSL15 includes 80 kB RAM and is available in 284 kB or 512 kB Flash options.

  • Industry leading general-purpose microcontroller (MCU)
  • Industry’s Lowest Power Flash-based Secure Bluetooth Low Energy MCU
  • Latest in Embedded Security with Root of Trust
  • Bluetooth Low Energy 5.2 with Long Range and Localization

The comprehensive, yet easy-to-use Software Development Kit (SDK) provides sample applications that demonstrate the hardware capabilities to enable security with the Cybersecurity Platform, acquire sensor data in Smart Sense mode, configure the built-in power management and utilize Bluetooth Low Energy features.

Key Features

  • Bluetooth Low Energy 5.2 Certified with Key Features
  • Ultra-low Power Operation
  • Rx Sensitivity (BLE Mode, 1 Mbps): -96 dBm
  • Rx Sensitivity (BLE Mode, 2 Mbps): -94 dBm
  • Configurable Tx Power: -17 dBm to +6 dBm
  • Data Rate of 62.5 kbps to 2000 kpbs
  • Arm Cortex-M33 processor clocked up to 48 MHz
  • Cybersecurity Platform with Arm CryptoCell™-312 for End-to-end Product Security with Secure Boot, Root of Trust, Lifecycle Management, Secure Key Management, and Application and Data Security
  • Arm TrustZone® to enable secure execution zones
  • Two Flash Memory Sizes Available, 284 kB Flash
  • (NCH-RSL15-284-101Q40-ACG) or 512 kB Flash (NCH-RSL15-512-101Q40-ACG)
  • 80 kB RAM (64 kB user RAM, 16 kB RAM for Baseband)
  • Flexible Power Management: 1.2 V - 3.6 V VBAT.
  • Directly connect 1.5 V Silver-oxide or 3 V Coin Cells without any external active components
  • Two SPI ports with QSPI capability


  • Industrial automation and sensing
  • Connected medical sensors
  • Wearables
  • Asset tracking
  • Electronic tags and access control
  • Electronic labels
  • Data loggers
  • Smart appliances
  • Energy harvesting switches


RSL15 Power Consumption Evaluation Guide

Discover this spreadsheet tool by onsemi designed to allow those using the RSL15 for its Ultra-Low Power BLE capabilities to generate an estimated average current/power consumption and battery life, given the user’s specific operating conditions and our models, created using samples captured from a functional RSL15 firmware implementation.

This tool will allow users to specify the Operating Mode, Advertising/Connection Interval, VBAT Voltage, Tx Payload, and Tx Power, which will then be fed into our models to generate an estimate of the average current and power consumption that will be observed during firmware execution.


High-Level Block Diagram


RSL15-EVB: RSL15 Evaluation and Development Board

The RSL15 Evaluation and Development Board (EVB) is designed to be used with the RSL15 Software Development Kit. It is intended for evaluating the performance and capabilities of RSL15, and for developing, demonstrating and debugging software applications for this device.

onsemi — RSL15-EVB Evaluation and Development Board
Eval Board User’s Manual

Key Features:

  • RSL15 wireless MCU with 512 kB Flash
  • Easy code download and debugging with SEGGER® J-Link® on-board technology
  • JTAG debug port accessible via 10-pin header
  • Automatic power supply switching between battery and USB
  • Access to all RSL15 interfaces and GPIOs via standard 0.1 inch headers
  • 2 push button switches - 1 dedicated to resetting the device via the NRESET pin - 1 connected to a GPIO


The comprehensive yet easy to use Software Development Kit (SDK) contains drivers, libraries, sample code, development tools and mobile apps: