Today’s 32-bit microcontrollers are practically everywhere, doing everything in the embedded space. Vendors continue to add more functionality, including advanced wireless connectivity, security, powerful motion control engines and more.
The term system-on-chip could arguably have been applied to 32-bit microcontrollers (MCUs) long before the term SoC ever emerged. For years, these MCUs have provided a mix of processing, memory and I/O on a single chip. And, as embedded systems have evolved, so too have 32-bit MCUs. The most sweeping trend in recent years has been the addition of wireless connectivity to these devices.
Driven mostly by the blossoming IoT phenomenon, today’s crop of MCUs includes many product offerings that include on-chip wireless connectivity. This has taken the form of support for Bluetooth Low Energy (BLE), Wi-Fi and other technologies. With MCUs embedded in systems across a wide diversity applications and industries, it’s hard to make any general statement about how they are used Aside from IoT, the leading MCU application areas include automotive, industrial systems, smart city, smart home, wearable devices and medical gear.
In an example of a 32-bit MCU application, the all-student Stanford Solar Car Project, from Stanford University, chose STMicrolectronics’ 32-bit STM32F4 MCUs for various applications in their solar car, Arctan. The Arctan was built to compete in the 2015 World Solar Challenge (Figure 1). That competition started in Darwin, Australia, crossed the Outback and ended 3,000km away in Adelaide one week later. In their Arctan vehicle, the Arm Cortex-M core-based STM32F4 MCUs monitored battery life and solar-panel efficiency and managed the electric motor and driver-control functions. According to ST, the Arctan was the fourth Stanford solar car with ST components. The STM32 MCUs optimize car performance based on real-time analysis of vehicle and environmental conditions.
One of the most recent trends in 32-bit MCUs is the strategy of taking a particular functionally that used to be its own IC and combining it with a 32-bit MCU on one chip. One example is Infineon Technologies’ IMC301A-F064, a motion controller and an Arm Cortex-M0 MCU in one device. Each of the leading vendors have a variety of 32-bit MCU product lines in a myriad of versions. With that in mind, the MCUs in the product gallery displayed on the next couple of pages are a representative sampling the most recent MCU technologies available today.
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • APRIL 2020 #357 – Get a PDF of the issue
Low-Power MCU Supports Bluetooth Mesh Networking
The CYW20819 from Cypress Semiconductor is a Bluetooth 5.0-compliant, standalone baseband processor with an integrated 2.4GHz transceiver with support for BLE, BLE 2Mbps, EDR 2Mbps and 3Mbps, synchronous connection-oriented (SCO) and extended SCO (eSCO). The device is intended for use in audio, IoT, sensors and HID markets.
• 32-bit 98MHz Arm Cortex-M4 CPU
• Complies with Bluetooth 5.0
• Support for BR, EDR 2Mbps and 3Mbps, eSCO,
• BLE and LE 2Mbps
• 256KB on-chip secure flash; 176KB on-chip RAM
• AES-128 and TRNG
• Up to 40 GPIOs; I2C, I2S, UART and PCM interfaces
• Two Quad-SPI interfaces
• Auxiliary ADC with up to 28 analog channels
Motor Controller Features
Arm Cortex-M0-Based MCU
Infineon Technologies’ IMC301A-F064 combines the Motion Control Engine (MCE 2.0), scripting and Arm Cortex-M0 MCU in QFP-64 package. The motor controller performs sensor less field-oriented control (FOC) for a variable speed drive based on a permanent magnet synchronous motor (PMSM). The integrated MCU is based on a 32 bit Arm Cortex-M0 core and is used to implement customer functionality.
• 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
• Internal oscillators and external oscillator support
• Window watchdog; real-time clock
• Pseudo random number generator
IoT MCU Provides 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 the most 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
Arm Cortex-M7 MCUs are Rad-Tolerant
Microchip Technology’s SAMV71Q21RT 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
PSA Certified MCU Provides Secure Flash Solution
Nuvoton Technology’s NuMicro M2351SF chip is based on M2351 IoT security MCUs and Winbond TrustME W77F Secure Flash. The M2351 Series is the first Arm Cortex-M23 based MCU that has been both PSA Certified Level 1 and PSA Functional API Certified, according to Nuvoton. The M2351SF is enhanced for its secure storage inside by stacking the Winbond W77F Secure Flash solution.
• Secure Storage Security
• 4MB flash memory density
• LQFP-128, LQFP-64 and QFN-33 packages
• Countermeasures against several kinds of attacks
• TrustZone Security and Low Power
• TrustZone for Armv8-M based on Cortex-M23 CPU
• Low-power consumption with LDO or DC-DC power supply
• Execute only memory (XOM)
• Cryptographic hardware accelerators
NuMicro M2351SF datasheet
Zigbee/Thread Wireless MCUs Embed 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
MCU Blends Advanced Security and Bluetooth 5
The RX23W MCUs from Renesas Electronics incorporate security functions that are vital for Bluetooth 5.0 Low Energy (BLE) and IoT devices, as well as a wealth of peripheral functions such as touch keys, USB and CAN, enabling system control and wireless communication with devices using a single chip. RX23W MCUs have full function support for Bluetooth 5.0 Low Energy long range and mesh networking.
• RXv2 core 54MHz (4.33 CoreMark/MHz)
• 1.8V to 3.6V operation
• Operating temperature -40°C to 85°C
• Flash max. 512KB, SRAM Max. 64KB
• Bluetooth Low Energy x1 ch.
• Built-in Bluetooth 5.0-compliant RF transceiver and link layer
• 1x CAN, 1x SD Host interface
• Capacitive touch sensing
• 12-bit ADC x14 ch., 12-bit DAC x2 ch.
• Trusted Secure IP Lite (AES/TRNG)
IoT MCUs Boast Security and Ultra-Low Power
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
• 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 from -40°C to +125°C
MCU Family Adds EtherCAT, Ethernet and CAN FD
The TMS320F2838x from Texas Instruments is a 32-bit floating-point MCU designed for advanced closed-loop control applications. The integrated analog and control peripherals with advanced connectivity peripherals like EtherCAT and Ethernet let designers consolidate real-time control and real-time communications architectures, reducing requirements for multi-controller systems.
• Dual-core 200 MHz C28x architecture
• IEEE 754 double-precision (64-bit) FPU
• 512KB of flash on each CPU
• 44KB of local RAM on each CPU
• EtherCAT slave controller (ESC)
• 10/100 Ethernet 1588 MII/RMII
• USB 2.0 (MAC + PHY)
• 2x CAN modules (pin-bootable)
• 4x ADCs, 8x windowed comparators with 12-bit DAC references
Plus1 Linux IIoT SoC
Plus1 is a revolutionary SoC featuring the power of a Linux-grade processor combined with the integration simplicity of a microcontroller. Unlike competing chips repurposed for IoT applications, Plus1 provides ample general-purpose I/O lines while remaining easy to integrate. Its LQFP package facilitates the use of two or four-layer PCBs.
• Quad-core 1GHz Cortex-A7
• A926 real-time core
• 8051 low-power core
• Single 3.3V power supply generates all additionally required voltages
• 512MB embedded DDR DRAM
• 72 GPIO lines with 3.3V logic level and 5V tolerance
• Dual Ethernet MACs support daisy-chaining
• LQFT form factor simplifies design, fabrication and repair
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.