Renesas Adds Motor Control-Focused Variant to High-End MCU Line

Renesas has announced the newest addition to its RA microcontroller line, the RA8T2. The newest MCU adds enhanced motor control and high-speed networking to the series, along with robust security features.

The new RA8T2 motor-control-targeted MCU. 

The RA8T2 is built around a 1-GHz Cortex-M85 with a 250-MHz Cortex-M33 for support tasks in some group variants. It adds high-precision, high-performance motor control in manufacturing, robotics, and other top-tier motor control applications. The Cortex-M85 includes Arm’s Helium technology, which is designed to help with digital signal processing (DSP) and machine learning (ML) functionality. 

High-Performance Motor Control

Renesas designed the RA8T2 with a focus on advanced motor control capability and real-time responsiveness. Its timer function supports pulse width modulation (PWM) at up to 300 MHz for motor control and power inverter applications. The higher PWM frequency delivers quieter (less audible noise) operation, lower motor temperatures, and reduced power losses. The MCU is capable of multi-phase, asymmetric, and complementary PWM drive. It automatically inserts dead time and quickly shuts down the PWM if it detects overcurrent. The timer comes with hardware phase counting capability for easier encoder development. 

RA8T2 block diagram (page 7 of the datasheet).

The MCU’s two 16-bit ADC units come with three channels, each with sample and hold functionality, enabling hardware monitoring of three-phase current. Users can also simultaneously manage two three-phase motors.

Memory Configuration

The RA8T2 includes 2 MB of SRAM, 256 KB of CM85 tightly coupled memory (TCM), 128 KB of CM33 TCM, 2 MB of SRAM, 2 x 64K cache, and up to 8 MB of flash. TCM is tightly coupled to the processor for low-latency operations. It gives a speed boost similar to cache. However, unlike cache, TCM is accessed as a part of the physical memory map and is not duplicated elsewhere. TCM allows the developer to specifically put critical routines closer to the CPU and keep them there based on priority of need rather than frequency of use. These might be interrupt-related, exception handling, or real-time routines. Data can also be placed in TCM if needed for extra fast access. TCM will typically have a single cycle capture or store time.

The MCU also holds up to 1 MB of magnetoresistive RAM (MRAM). MRAM is a nonvolatile memory with performance in line with conventional SRAM. It isn’t a new technology, having been developed in the 1980s. However, only recently has it been developed to a state where it is practical to integrate into mainstream applications. In the RA8T2, the MRAM has a 100-MHz access speed.

Communications and Security

Communications support includes two Gigabit Ethernet MACs with DMA and a two-port EtherCAT slave for both synchronous and asynchronous Ethernet. It supports a broad set of other popular protocols as well.

The chip is equipped with a robust set of security features to allow it to survive in today’s threat-prevalent world. It includes Renesas Security IP in hardware, Arm Trustzone security, privileged control, secure boot, and decryption on-the-fly (DOTF). Encryption support includes AES (128/192/256), RSA 4K, ECC, TRNG, SHA-2 (224/256/384/512), and SHA-3. 

RA8T2 feature set.

The RA8T fits into the top-tier motor control and analog notch of Renesas’ RA family lineup. The part comes in three package options: 11 mm x 11 mm (224-lead BGA), 12 mm x 12 mm (289-lead BGA), and 24 mm x 24 mm (176-lead QFP). It is available for purchase now, along with Renesas' flexible software package (FSP) and flexible motor control development kit.

All images used courtesy of Renesas.