Focused Feature Sets
Unlike microprocessors, microcontrollers (MCUs) tend to be used for specific applications. But even among MCUs, there’s a trend toward MCUs that are designed with features suited for very specific application segments, or even sub-segments.
While most MCUs are aimed a general market, a class of MCUs has emerged that provides tailored feature sets aimed at targeted application needs. These application-specific MCUs give embedded systems developers right-sized solutions with the feature sets, packaging or performance levels tailored to fit their system requirements.
Among MCUs, there’s distinct difference between general purpose MCUs and MCUs that are designed for very specific application segments or sub-segments. These application-specific MCUs usually have carefully selected on-chip IP cores and peripherals that meet the requirements unique to an application need.
To keep pace with the demands of embedded systems developers, over the past 12 months MCU vendors have continued to roll out these MCUs that address application needs in motor control, security, locking systems and even space. For their part, automotive MCUs are a particularly large and extremely active segment of application-specific MCUs. That said, those automotive MCUs are not addressed in this article. For a recent look at technology and product trends in automotive MCUs, check out our recent August Special Feature “Diverse IC Types Drive Automotive Innovations” (Circuit Cellar 361).
An example of an application-specific MCU is Microchip Technology’s SAM3X8ERT radiation-tolerant MCU (Figure 1). The device embeds the widely-deployed Arm Cortex-M3 core processor, delivering 100 DMIPS performance from the same ecosystem as Microchip’s industrial variant of this MCU.
This MCU provides up to 512KB of dual bank flash, 100KB of SRAM, ADC, DAC and dual CAN controller on top of Ethernet capability. This space-qualified MCU features ceramic and hermetic packages, extended temperature range -40°C to 105°C and extended qualification flow equivalent to QML-V or QML-Q space grade. Radiation performance for the SAM3X8ERT is specified as SEL LET > 62MeV.cm2/mg (at 105°C), and TID up to 30Krad (Si).
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • SEPTEMBER 2020 #362 – Get a PDF of the issue
Arm Cortex-M0-Based MCU for Motor Control
TheIMC301A-F064 from Infineon Technologies combines the Motion Control Engine (MCE 2.0), scripting and Arm Cortex-M0 MCU in QFP-64 package. The motor controller performs sensorless field-oriented control (FOC) for a variable speed drive based on a permanent magnet synchronous motor (PMSM).
• iMOTION Motion Control Engine (MCE 2.0)
• Integrated MCU with 32-bit Arm Cortex-M0 core
• High speed interface between MCE and Arm processor
• 128KB flash memory with ECC
• 3.3V to 5.5V supply with power-on-reset
• Internal oscillators and external oscillator support
• Window watchdog; real-time clock
• Pseudo random number generator
IoT Security MCU Embeds PUF Key Protection Tech
Maxim Integrated’s MAX32520 ChipDNA is a secure Arm Cortex-M4 MCU with built-in physically unclonable function (PUF) technology for financial and government-grade security. Maxim’s PUF technology allows for multiple layers of protection to provide advanced key-protection technology in a cost-effective format for use in IoT, healthcare, industrial and computing systems.
• Arm Cortex-M4F with FPU up to 120MHz
• 2MB PUF encrypted flash memory with cache
• Low latency on-the-fly decryption of flash execution
• 136KB SRAM + 34KB ECC
• 8KB user-programmable OTP
• Secure boot loader with PSA and serial flash emulation
• AES, SHA, and ECDSA accelerators
• Single 3.3V/2.5V/1.8V supply
• Down to 3.2μA backup mode
• 15μs wake-up time from standby mode
MAX32520 ChipDNA datasheet
Space-Qualified MCU With Arm Cortex-M7 Core
The SAMV71Q21RT from Microchip Technology is the radiation tolerant version of the Microchip SAMV71Q21 based on the high-performance 32-bit Arm Cortex-M7 processor with a double precision FPU. These devices operate at up to 300MHz and feature up to 2,048KB of flash, and up to 384KB of multi-port SRAM which is configurable.
• Arm Cortex-M7 running up to 300MHz
• No single event latch-up below a LET threshold of 60 MeV.cm2 /mg at 125°C
• Total ionizing dose of 30 krad(Si)
• 16KB of ICache and 16 KB of DCache with ECC
• Single- and double-precision HW FPU
• Memory protection unit (MPU) with 16 zones
• DSP instructions, Thumb-2 instruction Set
• Embedded Trace Module (ETM) with instruction trace stream
• Trace Port Interface Unit (TPIU)
• Temperature range -55°C to 125°C
Wireless MCUs Provide Zigbee, Thread and NFC
The JN5189 and JN5188 are IEEE 802.15.4 wireless MCUs from NXP that provide ultra-low power connected intelligence for Zigbee 3.0 and Thread applications. The JN5189 and JN5188 provide an integrated NFC NTAG while supporting a wide operating temperature range (-40°C to +125°C). They also include MCU peripherals for smart home, building automation, sensor network and other battery powered applications.
• Up to 48MHz Cortex-M4
• Up to 640KB flash, up to 152KB RAM, 128KB ROM
• NFC NTAG Option with EEPROM
• Quad-SPI for execute in place or data storage in NVM
• 2.4 GHz IEEE 802.15.4 compliant
• AES256 with hardware protected key
• Hash engine (SHA256), Code readout protection
• UART/SPI/I2C up to 2
• ISO7816 interface for Secure Access Module
• 8 ch. 12-bit ADC, 1 analog comparator
MCUs Enable Efficient
Inverter Control in Motors
The RX13T Group of MCUs from Renesas Electronics are equipped with the RX Family RXv1 core operating at 32MHz, a floating-point unit (FPU), an inverter control timer and a 12-bit ADC, allowing high-efficiency inverter control of brushless DC motors with one device. They are highly compatible with existing RX devices so it is easy to convert hardware and software from previous designs.
• RXv1 core operating at 32MHz operation (3.12 CoreMark/MHz)
• Floating Point Unit (FPU)
• 2.7V to 5.5V operation
• Operating temperature range:
-40°C to 105°C
• Memory resources: 128KB flash, 12KB SRAM and 4KB data flash
• Inverter control timer
• 12-bit, 8-channel ADC
with 3 channel simultaneous sample and hold circuit
• 3-channel comparator and a 3-channel PGA
• High-speed clock oscillator (HOCO) with 1% accuracy
RX13T Group datasheet
Ultra-Low Power MCUs Target IoT Security
STMicroelectronics’ ultra-low-power STM32L5x2 MCUs emphasize security to assure better protected IoT-connected applications. Operating at clock frequencies to 110MHz, the STM32L5- series MCUs start from the Arm Cortex-M33 32-bit RISC core with Arm TrustZone hardware-based security. The chips’ proprietary security builds on Arm TrustZone technology to achieve PSA Certified Level 2 certification.
• 110MHz Arm Cortex-M33 32-bit RISC core
• Arm TrustZone hardware-based security
• AES 128/256-bit key hardware acceleration
• Public key acceleration (PKA)
• AES-128 On-The-Fly Decryption
• 512KB dual-bank flash with ECC; 256KB-SRAM
• Standard temperature grade:
-40°C to +85°C
• High temp grade specified at
-40°C to +125°C
Jeff served as Editor-in-Chief for both LinuxGizmos.com and its sister publication, Circuit Cellar magazine 6/2017—3/2022. In nearly three decades of covering the embedded electronics and computing industry, Jeff has also held senior editorial positions at EE Times, Computer Design, Electronic Design, Embedded Systems Development, and COTS Journal. His knowledge spans a broad range of electronics and computing topics, including CPUs, MCUs, memory, storage, graphics, power supplies, software development, and real-time OSes.