32-Bit MCUs for Servo Control with Dedicated Hardware Accelerators

Renesas Electronics Corporation introduced the RX72T Group of 32-bit motor control, microcontroller units (MCUs).

The MCUs are equipped with dedicated hardware accelerator IP to perform the complex, high-speed computations needed for motor control in robots and other industrial equipment. The company also offers a Starter Kit for the RX72T. (See image above).

The RX72T Group delivers achieves an 1160 CoreMark score as measured by EEMBC® Benchmarks--the highest level for a 5V MCU operating at 200MHz. CoreMark is a benchmark test designed specifically for evaluating CPU core performance by the Embedded Microprocessor Benchmark Consortium (EEMBC^®) of the United States.

"The RX72T Group brings leading performance to our extensive lineup of MCUs optimized for industrial robotics and motor control, with built-in IP, safety and security functions, and advanced control," said Akira Denda, Vice President, Industrial Automation Business Division, Renesas Electronics Corporation. "The new MCU group extends an easy migration path across the RX family that creates new possibilities for extremely low-cost designs in compact industrial robots, and we are excited to accelerate the deployment of these applications to improve manufacturing efficiencies in industrial environments."

Features

The demand for compact industrial robots is rising. Implementing the complex motions of industrial robots requires high-precision control of a motor's position, direction, speed, and torque.

Dedicated accelerator hardware enables the high-speed position control and speed control calculations needed for implementing this precise servo motor control. The dedicated accelerator hardware allows the current control loop calculation to be performed in less than 1.5µs.

This hardware offers a new option for users to independently develop servo systems. Previously engineers could only purchase existing servo systems.

Implementing calculations in software can demand excessive computing time.

On the other hand, using completely hardware-based calculations can adversely affect the flexibility to implement custom user control operations.

The RX72T MCUs implement just the single-precision floating point trigonometric function (sin, cos, hypot, and arctan) and a register bank save function in hardware as dedicated IP. These basic functions enable the MCU to retain the design flexibility while increasing the calculation speed. Also, the register bank save function boosts the speed and precision of interrupt handling, enhancing the device's computation performance.

The MCUs include 200MHz PWM inverter control timers. These inverter control timers have up to 4 channels of 3-phase control, 2 channels of 5-phase control, or 10 channels of single-phase control.

The company's Failure Detection e-AI Solutions for motors to improve production and productivity can be coupled with the new RX72T MCUs.

Characteristic data such as current and speed values can be used directly to provide motor control and e-AI-based failure detection with a single MCU. Hardware-based system failsafe functions are included, and a hardware cryptography module can be used to encrypt/decrypt communications data.

Renesas offers programs that perform sensorless vector control and encoder vector control. The company provides the Renesas Motor Workbench 2.0 for real-time debugging and an RX72T CPU card that supports the 24V motor control evaluation kit.

The new RX72T MCUs offer a smooth migration path from the company's new high-end MCUs out to the RX66T (160MHz), RX23T (40MHz), and RX24T (80MHz) MCUs, giving design flexibility within the company's RX MCU environment.

Noteably, the RX72T Group is fully compatible with the RX66T Group incorporating the RXv3 core.

Starter Kit for RX72T

The company also offers the Starter Kit for RX72T for developers who are new to the RX72T(Code Flash 1MB, Pin Count 144-pin).

The kit includes an LCD display module and an on-chip debugging emulator. The integrated development environment is provided by Renesas Web, allowing users to start evaluating RX72T immediately after opening the box.

Key Features

• 32-bit RXv3 CPU core
  • Maximum operating frequency: 200MHz
  • Capable of 1160 CoreMark in operation at 200MHz
  • JTAG and FINE (one-line) debugging interfaces
  • A function for collectively saving the values of registers is available.
• Low-power design and architecture
  • Operation from a single 2.7V to 5.5V supply
  • Four low-power modes
• On-chip code flash memory
  • Supports versions with 1MB/512KB
  • No wait cycles at up to 120MHz or when the ROM cache is hit
  • User code is programmable by on-board or off-board programming.
• On-chip data flash memory
  • 32KB, reprogrammable up to 100,000 times
  • Programming/erasing as background operations (BGOs)
• On-chip SRAM, no wait states
  • 128KB of SRAM (no wait states)
  • 16KB of RAM with ECC (with wait)
• Data transfer
  • DMACa: 8 channels
  • DTCa: 1 channel
• ELC
  • Module operation can be initiated by event signals without using interrupts
  • Linked operation between modules is possible when the CPU is in sleep mode
• Reset and supply management
  • Power-on reset (POR)
  • Low voltage detection (LVDA) with voltage settings
• Clock functions
  • Frequency of resonator for main clock oscillator: 8MHz to 24MHz (this can be used as the PLL reference clock)
  • High-speed on-chip oscillator: 16MHz/18MHz/20MHz (this can be used as the PLL reference clock)
  • Low-speed on-chip oscillator: 240kHz
• Independent watchdog timer
  • 120kHz IWDT-dedicated on-chip oscillator clock operation
• Useful functions for IEC60730 compliance
  • Oscillation-stoppage detection, functions for self-diagnosis and detection of disconnection for the A/D converter, clock frequency accuracy measurement circuit, independent watchdog timer, RAM test-assisting function by DOC, and CRCA, etc.
  • Register write protection function can protect values in important registers against overwriting.
• External bus
  • Bus clock at 40MHz (max)
  • Four CS areas
  • 8- or 16-bit bus space is selectable per area

Pricing and Availability

Beginning in Q4 of 2019, the MCUs will be available in mass production quantities beginning. The 512KB flash, 100-pin R5F572TFBDFP device will be priced at US$4.06 in 10,000-unit quantities. Additional pricing will depend on the memory and pin-count configuration. Pricing and availability of the new MCUs is subject to change without notice.