New Industry Products

Dual-Core Wireless MCUs Support Bluetooth 5, Thread, and Zigbee 3.0

February 26, 2019 by Scott McMahan

STMicroelectronics has introduced its STM32WBx5 dual-core wireless microcontrollers (MCU). The MCUs come with Bluetooth® 5, OpenThread, and ZigBee® 3.0 connectivity combined with ultra-low-power performance. According to ST, the dual-core MCUs bring together the features of ST's STM32L4 Arm® Cortex®-M4 MCUs and in-house radio managed by a dedicated Cortex-M0+. The MCUs boast real-time performance as well.

The line of MCUs feature power-conscious design yet are capable of concurrent wireless-protocol and real-time application execution. They are suited for applications including remote sensors, wearable trackers, building-automation controllers, computer peripherals, drones, and other IoT devices.

Security features strengthen the STM32WBx5's IoT credentials and include Customer Key Storage (CKS), Public Key Authorization (PKA), and encryption engines for the radio MAC and upper layers. Security managed by the Cortex-M0+, includes OTA secure firmware update for application and radio stack, protection of device integrity and intellectual property, and ensuring easy, robust product management.

Extensive feature integration allows minimization of bill-of-material costs and footprint. STM32WBx5 MCUs have up to 1MB of on-chip Flash and a Quad-SPI port for efficient connection to external memory if needed. Additional features include crystal-less Full-Speed USB, 32MHz RF oscillator with trimming capacitors, a touch-sense controller, LCD controller, analog peripherals, and multiple timers, and watchdogs. The balun for antenna connection is also integrated.

Using the ultra-low-power technologies of STM32L4 line, the STM32WBx5 MCUs feature multiple power-saving modes.

These power saving modes include a 13nA shutdown mode, adaptive voltage scaling, and the adaptive real-time ART Accelerator™ for maximizing energy efficiency and ensuring long-lasting performance in self-powered applications.

ST optimized the integrated radio transmitter for high RF performance and low power consumption to maximize battery runtime. The RF output power is programmable up to +6dBm in 1dB increments, and the MCU draws only 5.2mA when transmitting at 0dB. Receive sensitivity is -96dBm for BLE communication at 1mbps. Designed for a link budget of 102dB, the radio ensures robust communication over long connection distances and includes support for an external PA.

ST says that the rich STM32Cube ecosystem facilitates the development with the STM32WBx5 line. Developers not only get free access to an extensive set of tools but can also take advantage of the STM32CubeWB MCU package featuring peripheral drivers, middleware, and connectivity libraries, and the STM32WB55 Nucleo pack (P-NUCLEO-WB55). The dedicated STM32CubeMon-RF connectivity tool for RF testing and custom use-case scripting comes as a new addition to STM32Cube to further hasten time-to-market.

(Click on image to enlarge)

The STM32WBx5 comes in nine different variants with four package types. (See graph above). STM32WB55CG, STM32WB55RG, and STM32WB55VG have 1MB of flash memory and 256KB of RAM. STM32WB55CE, STM32WB55RE, and STM32WB55VE have 512KB of flash memory and 256KB of RAM. Whereas, STM32WB55CC, STM32WB55RC, and STM32WB55VC feature 256KB of flash memory and 128KB of RAM.

STM32WB55VG, STM32WB55VE, and STM32WB55VC come in a choice of two package types, a 100-pin WLCSP with a 0.4mm pitch and a 129-pin UFBGA with a 0.5mm pitch, and samples of these three are available.

STM32WB55RG, STM32WB55RE, and STM32WB55RC are available in a 68-pin VQFN package with a 0.4mm pitch. Whereas the STM32WB55CG, STM32WB55CE, and STM32WB55CC feature a 48-pin UQFN package with a 0.5mm pitch. These six variants are in production.

Key Features

Includes ST state-of-the-art patented technology
Radio
- 2.4GHz
- RF transceiver supporting Bluetooth® 5 specification, IEEE 802.15.4-2011 PHY and MAC, supporting Thread and ZigBee® 3.0
- RX Sensitivity: -96dBm (Bluetooth® Low Energy at 1Mbps), -100dBm (802.15.4)
- Programmable output power up to +6dBm with 1dB steps
- Integrated balun to reduce BOM
- Support for 2Mbps
- Dedicated Arm® 32-bit Cortex® M0 + CPU for real-time Radio layer
- Accurate RSSI to enable power control
- Suitable for systems requiring compliance with radio frequency regulations ETSI EN 300 328, EN 300 440, FCC CFR47 Part 15 and ARIB STD-T66
- Support for external PA
Ultra-low-power platform
- 1.71V to 3.6V power supply
- - 40°C to 85°C/105°C temperature ranges
- 13nA shutdown mode
- 600nA Standby mode + RTC + 32KB RAM
- 2.1µA Stop mode + RTC + 256KB RAM
- Active-mode MCU: < 53µA/MHz when RF and SMPS On
- Radio: Rx 4.5mA/Tx at 0dBm 5.2mA
Core: Arm® 32-bit Cortex®-M4 CPU with FPU, adaptive real-time accelerator (ART Accelerator™) allowing 0-wait-state execution from Flash memory, frequency up to 64 MHz, MPU, 80 DMIPS and DSP instructions
Supply and reset management
- High efficiency embedded SMPSstep-down converter with intelligent bypass mode
- Ultra-safe, low-power BOR (brownout reset) with five selectable thresholds
- Ultra-low-power POR/PDR
- Programmable voltage detector (PVD)
- VBAT mode with RTC and backup registers
Clock sources
- 32MHz crystal oscillator with integrated trimming capacitors (Radio and CPU clock)
- 32kHz crystal oscillator for RTC (LSE)
- Internal low-power 32kHz (±5%) RC (LSI1)
- Internal low-power 32kHz (stability ±500 ppm) RC (LSI2)
- Internal multispeed 100kHz to 48MHz oscillator, auto-trimmed by LSE (better than ±0.25% accuracy)
- High speed internal 16MHz factory trimmed RC (±1%)
- 2x PLL for system clock, USB, SAI and ADC
Memories
- Up to 1 MB Flash memory with sector protection (PCROP) against R/W operations, enabling authentic Bluetooth® Low Energy and 802.15.4 SW stack
- Up to 256KB SRAM, including 64KB with hardware parity check
- 20x32-bit backup register
- Boot loader supporting, USART, SPI, I2C and USB interfaces
- OTA (Over the air) Bluetooth® Low Energy and 802.15.4 update
- Quad SPI memory interface with XIP
Rich analog peripherals (down to 1.62V)
- 12-bit ADC 4.26Msps, up to 16-bit with hardware oversampling, 200µA/Msps
- 2x ultra-low-power comparator
- Accurate 2.5V or 2.048V reference voltage buffered output
System peripherals
- Inter processor communication controller (IPCC) for communication with Bluetooth® Low Energy and 802.15.4
- HW semaphores for resources sharing between CPUs
- 2x DMA controllers (7x channels each) supporting ADC, SPI, I2C, USART, QSPI, SAI, AES, Timers
- 1x USART (ISO 7816, IrDA, SPI Master, Modbus and Smartcard mode)
- 1x LPUART (low power)
- 2x SPI 32Mbit/s
- 2x I2C (SMBus/PMBus)
- 1x SAI (dual channel high quality audio)
- 1x USB 2.0 FS device, crystal-less, BCD and LPM
- Touch sensing controller, up to 18 sensors
- LCD 8x40 with step-up converter
- 1x 16-bit, four channels advanced timer
- 2x 16-bits, two channels timer
- 1x 32-bits, four channels timer
- 2x 16-bits ultra-low-power timer
- 1x independent Systick
- 1x independent watchdog
- 1x window watchdog
Security and ID
- Secure firmware installation (SFI) for Bluetooth® Low Energy and 802.15.4 SW stack
- 3x hardware encryption AES maximum 256-bit for the application, the Bluetooth® Low Energy and IEEE802.15.4
- Customer key storage/key manager services
- HW public key authority (PKA)
- Cryptographic algorithms: RSA, Diffie-Helman, ECC over GF(p)
- True random number generator (RNG)
- Sector protection against R/W operation (PCROP)
- CRC calculation unit
- 96-bit unique ID
- 64-bit unique ID. Possibility to derive 802.15.5 64-bit and Bluetooth® Low Energy 48-bit EUI
Up to 72 fast I/Os, 70 of them 5V-tolerant
Development support
- Serial wire debug (SWD), JTAG for the Application processor
- Application cross trigger with input and output
- Embedded Trace Macrocell™ for application
All packages are ECOPACK®2 compliant