The new product line comprises a total of six new devices with pin counts ranging from 80 to 100 pins and on-chip flash memory capacities from 128 kilobytes (KB) to 256 KB. The RX24T Group enables simultaneous inverter control of multiple motors with a single chip and is suitable for permanent magnet AC (PMAC) motor control (Note 1) in various applications.
The RX24T Group offers up to 160 DMIPS, including dedicated analog functions to optimize the inverter bill of materials (BOM), and further increases arithmetic operation and expands the peripheral motor control functions of the cost-optimized RX23T.
In addition, Renesas plans to offer a 24V motor control evaluation kit (Note 2), which can support both single motor control (RX23T) and multi-motor control (RX24T).
Recently, many countries have imposed legal requirements mandating improved motor efficiency (Note 3), in addition to regulations aimed at reducing energy consumption. This has increased the demand for high-efficiency inverter control.
The main features of the new RX24T MCU group:1) With FPU chip functionality for faster code execution, the RX24T supports control of multiple high-performance engines for platform development with a wide range of products
The RX24T incorporates the RXv2 CPU core with a five-stage pipeline, a floating-point unit (FPU, Note 4), and DSP functions, performing 32-bit multiplication within a single instruction to improve the accuracy of algorithm calculations. In effect, the RX24T running at 80 MHz has performance levels similar to a 100 MHz MCU. The FPU chip functionality provides faster implementation of computationally intensive algorithms with a wide dynamic range.
The FPU allows the global code to be reduced, and global software implementations to run much faster, without saturation occurring.
Furthermore, the FPU ensures faster calculation times for PI controllers and estimators. The FPU simplifies debugging and can reduce development time by approximately 30 percent.
Furthermore, the RX24T Group of MCUs maintains excellent compatibility with the RX23T Group, enabling the reuse of existing hardware and software assets, increases CPU performance from 40 MHz to 80 MHz and Flash capacity from 128 KB to 256 KB, and doubles the power of the related chip's motor control peripheral functions (timers, A/D converters, and operational amplifiers) to enable the control of multiple permanent magnet AC motors by a single chip.
The RX24T also integrates fail-safe mechanisms in the hardware that allow for rapid implementation and execution of the automatic verification class B routines, which are mandatory for compliance with IEC60730-1 safety.
2) Renesas' flexible motor control development solution and tools allow for the evaluation of a sensorless vector control day.
Developing new motor systems capable of meeting the demands of a rapidly growing market requires short application development cycles and specialized expertise. Renesas has developed a 24V Flexible Motor Control Evaluation Kit (Note 2) for use with the RX23T and RX24T. This kit enables developers to quickly begin evaluating motor control applications. The kit includes a CPU board, a low-voltage inverter, a PMAC motor with the sensorless vector control driver software (Note 5), and sample demonstrations.
The kit also includes an ICS (In-Circuit Scope), a variable RAM waveform visualization tool that is indispensable for reducing development workload, providing safe debugging, and substantially reducing evaluation time. An intuitive auto-tuning tool allows users to fine-tune their engine in under a minute, greatly simplifying development and eliminating typical trial-and-error methods. Software and evaluation tools include support for CS+ and Studio e2 development environments, a code generation tool, C compilers, debuggers, and flash memory programmers.
In addition, the RX24T Starter Kit (Note 6) will also be available to provide a complete development environment for initial implementation, including an RX24T reference board and an MCU evaluation environment.
3) Fewer external components for smaller printed circuit boards
As applications become more compact, printed circuit board (PCB) sizes are shrinking, resulting in strong demand for microcontrollers (MCUs) that integrate the functions of external components. The RX24T integrates onto the chip the external circuitry required by the inverter control systems, such as operational amplifiers that support simultaneous amplification of four channels of three-shunt and single-shunt currents, comparators capable of detecting overcurrent in amplified current, sample-and-hold circuits that can handle up to five channels simultaneously, such as three-shunt currents, and DataFlash for storing registers and configuration files. This drastically reduces the required PCB footprint. The RX24T and RX23T also incorporate automatic PWM signal shutdown to ensure the protection of the three-phase bridges; this module, called "Port Output Enable" (PoE), sets the signals to a high-impedance state to protect the inverter.
