With the rapid development of Industrial Internet of Things (IIoT), more and more sensors need to be used in industrial application environments to detect the operating conditions of equipment. These sensors can use the new Bluetooth® Low Energy (BLE) microcontroller (MCU) that features both security and low power to improve the networking capability and operational efficiency of sensors. This article will show you the BLE microcontroller introduced by onsemi to understand its functional characteristics and application fields.
Wireless Connection Technology with Low Power and Security
From beacons used for contact tracking to traceable asset tags, millions of connected devices around the world use small batteries to operate. The power consumption requirements of the devices are particularly high, and low-power BLE wireless connection technology is required to improve the operating efficiency of the devices. BLE is a personal area network technology designed and promoted by Bluetooth Technology Alliance. Compared to Classic Bluetooth, BLE aims to significantly reduce power consumption and cost while maintaining the same communication range.
BLE technology uses the same operating frequency as Classic Bluetooth technology (2.400GHz-2.4835GHz, ISM band), but uses another set of channels. Different from the Classic Bluetooth 79 1-MHz channels, BLE uses 40 2-MHz channels. Within a channel, the data is transmitted using Gaussian frequency shift modulation, similar to Classic Bluetooth’s basic rate scheme, with the bit rate of 1Mbit/s and the maximum transmission power of 10mW.
In IIoT applications, the ability to defend against cyber threats is an important consideration when manufacturers choose wireless MCU. Advanced system-level security feature can provide well-established device security, avoid the device being hacked and affecting the information security of enterprises, and reduce the probability of system downtime. Security guarantees must be provided at the hardware, application and software levels.
New Secure BLE Wireless MCU Leading the Industry
onsemi, as the leader in intelligent power supply and sensing technology, has introduced a new type of secure RSL15 wireless MCU, which can provide the lowest power consumption in the industry, support BLE wireless connection capability, and meet the increasing security requirements of IIoT applications without sacrificing power consumption.
In order to validate energy efficiency, RSL15 has been certified by the Embedded Microprocessor Benchmark Alliance (EEMBC). The organization’s ULPMark™-CoreMark benchmark program can measure the energy efficiency of MCU used in embedded system during activity. RSL15 leads similar products with the "performance" score of 60.5. In the ULPMark-CoreProfile benchmark test for calculating MCU deep sleep efficiency, onsemi also remained in the top two with RSL10 and RSL15 respectively. Through certified energy efficiency performance, RSL15 will help industrial applications and many other applications to achieve longer battery life than expected.
While maintaining its state-of-the-art power consumption, RSL15 is designed with Arm® TrustZone® technology to establish a device root of trust, and Arm CryptoCell™-312 technology to protect the authenticity, integrity and confidentiality of codes and data. This PSA level 1 certified design is part of the Bluetooth protocol, which can enhance the security of the device and provide guarantee at the application and software level. With its advanced system-level security features and first-class energy efficiency, RSL15 can provide a comprehensive wireless solution that OEM and consumers can trust.
High Performance MCU Designed for Industrial Smart Device Applications
The RSL15 launched by onsemi is an ultra-low power security BLE 5.2 wireless MCU based on Arm® Cortex®-M33 processor, which is specially designed for connecting smart devices in industrial and medical applications. onsemi provides a comprehensive and easy-to-use software development kit (SDK) for RSL15, and sample applications that demonstrate the hardware functions of enabling security using the network security platform, and can obtain sensor data in Smart Sense mode, configure built-in power management, and take advantage of BLE technology features.
The built-in Arm Cortex-M33 of RSL15 is a 32-bit processor designed for Internet of Things and deeply embedded applications that require high performance, power efficiency and security. The processor has many features to perform high-performance applications, such as floating point unit (FPU), DSP extension and memory protection unit (MPU).
The Cortex-M33 processor of RSL15 supports TrustZone Armv8-M security expansion and forms the basis of the security platform. Arm CryptoCell-312 allows the use of Secure Boot with root of trust, security lifecycle management, security key management, and application and data encryption using symmetric or asymmetric cryptography to achieve end-to-end product security. Arm TrustZone can realize secure software access control and a variety of cryptographic services, such as SHA1, SHA256, keyed-hash message authentication code (HMAC) and true random number generator (TRNG), and allow the development of customized proprietary security solutions.
The RF architecture of RSL15 RF subsystem is based on 2.4 GHz RF front-end, which can realize BLE 5.2 standard physical layer and other proprietary or custom protocols. RF operation of RSL15. Bluetooth 5.2 certified baseband and protocol stack has features such as 2 Mbps RF link, Angle−Of−Arrival (AoA), Angle−Of−Departure (AoD), and Coded PHY (“Long Range”). The hardware supports the implementation of custom protocols and RSSI with enhanced localization capability.
The RSL15 has a built-in DC-DC converter with buck and LDO modes, which requires few external passive components that enable a broad voltage supply range. Any voltage in the range of 1.2 V to 3.6 V can be used directly without the need for external power conversion allowing for simple use of common coin cell batteries such as 3 V coins cells and 1.5 V silver oxide cells.
RSL15 has a variety of power modes to reduce power consumption while still maintaining system responsiveness. Each mode can be configured with RAM retention and wakeup sources. Smart Sense mode allows some digital and analog peripherals to remain active, monitoring and acquiring data from external sensors at a very low system-level power consumption.
Provision of complete peripheral configuration and system architecture
Two crystal oscillators and two internal RC oscillators are available on RSL15 to offer a variety of clocking configurations. The primary oscillator is based on a 48 MHz crystal, which is necessary for any connected RF operation. The secondary oscillator is based on a 32 kHz crystal, which can be used for precision timing even in low power modes. When precision timing is not required, the internal fast RC oscillator can be used in place of the 48 MHz crystal oscillator for general non-RF processing. Likewise, for some use cases, the internal 32 kHz RC oscillator can be used in place of the 32 kHz crystal oscillator. In addition, 48 MHz and 32 kHz external clocks can be driven into RSL15 from external clock sources.
Additionally, RSL15 has two analog-to-digital converters (ADCs), a high-speed 12-bit SAR ADC for fast conversion of analog inputs up to 2 Msps and Low Speed ADC for slower conversion up to 50 ksps. There is also an integrated temperature sensor that can be read by the Low Speed ADC.
RSL15 also has a flexible I/O interface. General I/O can be mapped to GPIO, SPI, QSPI, I2C, UART, PWM, PCM, pulse counter, clock input/output and analog functions. The RSL15 also has a built-in analog comparator, as well as a DAC for generating bias voltages for external components, and a current source output.
The memory architecture of RSL15 is centered around Arm Cortex-M33, and the flash memory contains application code and protocol stack. RSL15 has a built-in 80 kB RAM and provides flash memory options 284 kB or 512 kB. Its RAM architecture is very flexible allowing for powering only the amount of memory needed for the application. A total of 64 kB user RAM is available, implemented as 8 times 8 kB. An additional 16 kB is available for the digital baseband hardware. A DMA controller is available for easy data streaming between peripherals/interfaces and memories.
onsemi also launched a software development kit that supports RSL15, containing the Eclipse-based onsemi IDE installer, as well as support for other industry standard development environments, Bluetooth protocol stacks, sample applications, libraries, RSL15 firmware packages, and many other software components and tools to enable rapid application development. onsemi provides RSL15 Central and RSL FOTA apps that can be used on iOS®and Android™.
The RSL15 is packaged in the miniature 40-pin QFN package and is RoHS compliant. It can be used in various industrial automation and sensing fields, including interconnected asset tracking, smart retail and IoT edge nodes, and can also be applied to connected medical sensors, wearable devices, electronic tags and access control, data loggers, smart appliances, energy harvesting switches and other products.
Conclusion
BLE technology can meet the low power and security requirements of IIoT sensing applications. The RSL15, a ultra-low-power secure BLE 5.2 wireless MCU, introduced by onsemi has industry-leading energy efficiency performance and rich security features, and will be one of the best device choices for IIoT related product design.