Bluetooth LE 5.3 and security in a wireless MCU

STMicroelectronics has created a 40nm Bluetooth LE 5.3 wireless microcontroller family centred around a 100MHz Arm Cortex-M33 core – that's the security-enabled version of the Cortex-M3, which has TrustZone virtualisation.

Called STM32WBA52, the ICs are similar to the company's earlier Cortex-M4-based STM32WB wireless microcontrollers, and have a +10dBm 2Mbit/s 2.4GHz transceiver (10.6mA at 0dBm TX, 7.4mA Rx) that can support up to 20 simultaneous connections.

"STM32WBA52 targets Arm PSA Certified Level 3 and SESIP3 IoT security standards", according to ST. "The boost to cyber-protection comes from the PSA security program based on security isolation, memory protection, tamper protection, and Arm TrustZone. The platform is delivered with secure software based on Trusted Firmware for Arm Cortex-M."

This security software, it went on to explain, meets the PSA Certified security framework, with PSA immutable root-of-trust including secure boot and secure firmware update, cryptography, secure storage and attestation at runtime. The company has also included side-channel resistantant, it claimed, symmetric and asymmetric cryptographic accelerators and a hardware-unique key.

There are two parts so far, STM32WBA52CG with 1Mbyte of flash and 128kbyte of ram, then the …CE with 512k of flash and 96k of ram. For data integrity, both flash and ram get ECC (error code correction), and both devices come in a 7 x 7mm exposed pad UFQFPN48 package.

M33 100MHz (CoreMark = 407) operating power is 50µA/MHz ( 1.8V LDO 25°C), and there are 10 power modes all the way down to 140nA stand-by with everything off.

For development, there is a STM32CubeWBA package with a certified Bluetooth Low Energy 5.3 protocol stack for the STM32Cube tool-set. A dedicated dev board, Nucleo-WBA52CG, is planned.

The STM32WBA product page can be found here, and the data sheet here (which hints at similar parts in 5 x 5mm UFQFPN32 packaging).

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