STMicroelectronics Stellar P3E quad-core Arm Cortex-R52+ automotive MCU features Neural-ART AI accelerator

STMicroelectronics has introduced the Stellar P3E, the first automotive MCU with an embedded Neural-ART AI accelerator, designed to simplify X-in-1 Electronic Control Units (ECUs) by consolidating powertrain functions like the inverter, on-board charger (OBC), and DC-DC converter into a single module. The MCU enables smart sensing, predictive maintenance, and virtual sensor applications without the cost and complexity of a separate SoC.

The microcontroller features four 500 MHz Arm Cortex-R52+ cores with 19.5 MB of xMemory, which is based on phase-change memory (PCM), offering roughly twice the density of embedded flash. The chip integrates multiple ADC channels for precise sensing, high-resolution PWM down to 102 ps for fine motor control, and 10 timer modules for deterministic real-time operation. Connectivity options include Gigabit Ethernet and CAN-XL, for high-speed, low-latency in-vehicle communication.

Stellar P3E (SR6P3EC4/SR6P3EC6) specifications:

• MCU – SR6P3EC4 / SR6P3EC6
  • CPU Cores – 4x Arm Cortex‑R52+ cores at up to 500 MHz; Can be set as 4 cores (2 in lockstep) or 3 cores (all in lockstep)
    • Single precision floating-point unit (FPU)
    • Hardware-based virtualization architecture for software isolation in SDV applications
    • 16KB I-cache / 8KB D-cache per core
    • 128KB TCM per core
  • AI accelerator – Neural-ART proprietary NPU (INT8)
  • 1x Arm Cortex-M4 multipurpose core running at 200 MHz in lockstep for low-power modes and COM acceleration
• Memory and Storage
  • Up to 19.5MB xMemory (PCM-based NVM)
    • Up to 19MB code NVM with A/B swap OTA support
    • 512KB HSM-dedicated NVM
  • Up to 1792KB SRAM
  • 384KB data NVM (256KB + 128KB HSM)
  • Built-in dual-image OTA mechanism
• Connectivity – Gigabit Ethernet with AVB, VLAN, and 10BASE-T1S (SPE).
• Peripherals
  • Up to 106x analog input channels
  • 12x 12-bit SAR ADCs
  • 10x 16-bit Sigma-Delta ADCs (with DSP)
  • 4x 9-bit SAR analog comparators
  • 1x 9-bit low-power ADC (standby mode)
  • 4x eDMA engines (4× 32 channels)
  • GTM4134 Generic Timer Module
  • High-resolution timers (2× 8 channels)
  • 1x 64-bit Global System Timer (GST)
  • 9x software watchdog timers
• Communication
  • 10x CAN FD modules, 8× CAN FD + 2× CAN FD / CAN XL modules
  • 8x LINFlexD (Local Interconnect Network)
  • 1x Dual-channel FlexRay (deterministic, time-triggered automotive bus)
  • 10x SPIQ (2 with LVDS)
  • 2x I²C
  • 2x PSI5 (Peripheral Sensor Interface 5)
  • 2x MSC (Microsecond Channel)
  • 2x SENT (Single Edge Nibble Transmission; 20 channels total)
  • 1x LFAST (Low-Latency Fast Automotive Serial Transmission; C2C interprocessor bus)
• Safety and Security
  • 2nd-gen Hardware Security Module (HSM)
  • 2× AES-Light cryptographic subsystem (lockstepped)
  • Secure network-on-chip with QoS and firewalling
• Debug
  • Main debug port (JTAG+SWD)
  • Secondary debug port (SWD)
  • 1× High-speed off-chip trace lane (multi-Gbit/s, Aurora protocol)
• Power
  • Should be 5V capable, as it’s built on 28nm FD-SOI (input voltage is not mentioned by the company)
  • Standby ultra-low power mode
  • Smart low-power mode (with Cortex-M4 subsystem active)
• Package
  • FPBGA292 (SR6P3EC4, 17×17 mm)
  • FPBGA476 (SR6P3EC6, 21.3×21.3 mm)
•  Certifications
  • AEC-Q100 qualified
  • ASIL-D capable (ISO 26262)
  • ISO/SAE 21434 cybersecurity support
• Temperature – Maximum junction temperature of 150°C (target 165°C for specific implementations)

Software support for the Stellar P3E is built around the ST Edge AI Suite and Stellar Studio IDE, enabling model optimization, quantization, validation, and deployment on the embedded Neural-ART NPU. The platform also provides AUTOSAR MCAL drivers, RTOS support, OTA A/B firmware management, and safety libraries aligned with ISO 26262 ASIL-D requirements. Developers can also use NanoEdge AI Studio and pre-optimized models from the Model Zoo, while third-party toolchains from Green Hills, IAR, and PLS support certified compilation, debugging, and tracing for automotive applications.

For debugging, the company also provides StellarLINK, a USB-to-JTAG debugger and programmer for Stellar (SR5/SR6) and SPC5 automotive MCUs. It enables firmware programming, run-control debugging, and UART communication via a virtual COM port, and integrates with StellarStudio and SPC5-STUDIO IDEs.

The company also designed the SR6PX-EVBC4000P evaluation board, which supports only the SR6P3EC4 MCU in the BGA292 package. The socket-based board exposes various interfaces such as Automotive Ethernet, CAN FD, CAN XL, FlexRay, LIN, SPI, I²C, and UART, along with debug connectors and user I/O, enabling rapid prototyping and evaluation using StellarStudio and StellarLINK.

Other automotive-grade MCUs with AI features include the Geehy G32R501 Cortex-M52 AI MCU and the Renesas RA8T2 Cortex-M85 MCU for motor control. The Stellar P3E adds another option with four 500 MHz Cortex-R52+ real-time cores (over 8,000 CoreMark) alongside a dedicated Neural-ART NPU delivering up to 69 times faster inference (compared to running it on the MCU cores) for specific automotive workloads.

STMicro mentions that engineering samples are available, with full automotive qualification and mass production targeted for Q4 2026. The StellarLINK sells for $109.45, and the SR6PX-EVBC4000P evaluation board goes for $1,089. More details may be found on the product page and press release.

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