Renesas delivers new motor control MCUs with high-speed networking interfaces
Renesas has introduced the RA8T2 microcontroller (MCU) group for high-end motor control. Based on a 1 GHz Arm Cortex-M85 processor with an optional 250 MHz Arm Cortex-M33 processor, the RA8T2 devices deliver an unmatched level of performance to address real-time control of high-end motors in industrial equipment, robots, and other systems where high-speed precision operation is required. The optional Cortex-M33 processor enables customers to combine real-time control with communication functions and non-real-time operations on a single chip, saving cost, power and board space.
The RA8T2 MCUs take advantage of the high performance of the Arm Cortex-M85 processor and Arm’s Helium technology to offer a significant performance boost for digital signal processor (DSP) and machine learning (ML) implementations. This added performance enables AI functions that can predict maintenance requirements for motors, reducing costly downtime.
In addition to their processing power, the RA8T2 MCUs provide high-speed networking support through multiple communications interfaces, including two Gigabit Ethernet MACs with DMA, a two-port EtherCAT slave, and many others. High-speed communication is critical in factory automation, where each device is linked to a network within the factory, and is constantly synchronised with other machines to send and receive commands and data.
RA8T2 devices are equipped with up to 1MB of high-speed MRAM (Magnetoresistive Random Access Memory) non-volatile memory with 100 MHz access. MRAM offers faster write speeds along with higher endurance and retention compared with Flash. In addition, RA8T2 is equipped with a TCM (Tightly Coupled Memory) with 256KB for Cortex-M85 and 128KB for Cortex-M33. TCM provides users with high-precision real-time performance with less jitter and can provide stable performance in motor control processing with many interrupts and branches.
The new RA8T2 devices include a timer function that supports PWM functionality up to 300 MHz and enables easy handling by control software and efficient waveform generation for driving inverters. The complementary PWM function of the GPT timer, optimised for inverter drive, makes it easy to implement control algorithms, such as the output of complementary PWM for multiple phases (including single-phase and three-phase), automatic insertion of dead time, generation of asymmetric PWM, and linkage with AD and comparators. The timer is also equipped with a phase-counting function, making it possible to control AC servos that require axis position information using a two-phase pulse encoder. The RA8T2’s ADC has 16-bit resolution and a channel-specific sample and hold function (three channels), enabling high-precision simultaneous sampling of three-phase current values. This eliminates the need for correction processing, reducing the software load and contributing to improved control precision. Equipped with two units, it is possible to simultaneously sample three-channel currents of two motors. The Port Output Enable (POEG) and high-speed comparator function allows the PWM output to be quickly shut off when an overcurrent is detected. The shutoff state can be selected (Hi-z, Hi, Low) according to the inverter specifications.
