IoT Microcontroller Chip Selection
The IoT structure is comprised of the edge nodes, the gateway nodes/hubs, and the cloud/datacenter. The interface between the virtual, digital world of the Internet or local network, and the real, analog world is provided by the edge nodes. An edge node is the "thing" in the IoT. Based on the type of application, the edge node can gather and/or receive sensed data, process and transmit it to the network. Hence, the functionality of the edge node can be described in terms of its integrated microcontroller and the associated transducers, interfaces, processing and communication to the network.
The IoT microcontrollers(MCU) with Ultra Low Power (ULP) are the computing engines that powers the edge of the Internet of Things (IoT). The ‘things’ living on the edge utilize Microcontrollers (MCUs) to handle user interfaces, collect and transmit sensor data, and provide security features. Hence, the application developers are challenged with a number of optimization challenges to ensure the very low power operation over periods of years and decades.
The MCU market has a strong relationship with the IoT trend, as the small nodes used for connectivity, and sensor hubs to collect and log data, are primarily based on MCU platforms. The IoT related MCU market is predicted to reach US $2.8 billion in 2019.
Security – Inarguably a prime factor to consider!
According to a study, it’s found that 70 percent of popular consumer IoT devices are easily hackable. It’s strongly advised to design and develop IoT solutions by adopting a multilayer approach that integrates device and data security into IoT solutions irrespective of the IoT device’s intended field of operation (industrial, commercial, or consumer systems). Effective device security would require efficient security processes, solid isolation of the security code and keys, and protection against both remote and physical attacks.
Being at the center of the IoT hardware, the selection of IoT microcontrollers is of great importance and indeed a tedious task itself. Given the IoT application, the foremost considerations to make while choosing the semiconductor chip (microcontroller or MCU) are given below.
Features / Functions neede
1. Integrated security (tamper resistance, optional JTAG lockout, CRC-16 and AES- 128 routines in ROM, reserved flash space for UID, true random number generator, etc.,).
2. Power-efficient at the edge (battery powered).
3. Wider software market (access to internal registers, debugging capabilities, etc.,).
4. Internet protocols supporting latest wired and wireless connectivity technologies.
Microcontroller-specific Chip Parameters / Specifications:
1. Very low power (Radio, Standby, Operating)
2. Data bus width (4, 8, 16, 32 bits)
3. Clock and CPU speed (MHz)
4. Device core (ARM, PIC, STM8, MSP430, RISC, etc.,)
5. Memory type and size – Data RAM and Program(Flash, EPROM, ROMLess, etc.,)
6. Number of I/O’s (Debug interface, DC-DC converter, Transceivers, etc.,)
7. Number of Timers (Independent RTCs, Periodic interrupt timers, Programmable delays, etc/.)
8. Interface Type (WiFi, Bluetooth, I2C, CAN, CMT, SPI, LPUART, TSI, NFC, etc.,)
9. ADC and DAC Channels
10. Supply or Input Voltage
11. Operating Temperature Range
Sample list of IoT MCUs from Top Manufacturers:
|Manufacturer Name||Product Series||Product Family||CPU||Operating Voltage|
|Analog Devices||AduCM3027, AduCM3029||Ultra low Power||Cortex-M3||1.74 to 3.6 V|
|Atmel / Microchip||SAM4S||SMART SAM4S||Cortex-M4|
|Intel||D2000||Quark||2.0 to 3.3 V|
|NXP||LPC1100||Cortex-M0||1.71 to 3.6 V|
|Silicon Labs||EFM32||Pearl Gecko, Wonder Gecko||Cortex-M4|
|ST Micro||STM32||Ultra low Power||Cortex-M4||1.71 to 3.6 V|
|MSP432||Cortex-M4||1.62 to 3.7 V|
|Manufacturer Name||Memory and Clock Speed||Operating Temperature|
|Analog Devices||128kB or 256kB of Embedded Flash, 64kB SRAM, 4kB Cache||-40°C to 85°C|
|Atmel / Microchip||Upto 2MB Flash, 160kB SRAM, 120MHz|
|Intel||32kB Instruction Flash, 8kB SRAM, 4kB Data Flash, 32MHz|
|NXP||32-bit, 128-512kB Flash, upto 128kB SRAM, 48MHz||-40°C to 105°C|
|NXP||32-bit, 4kB SRAM, 16kB Flash, 50 MHz||-40°C to 85°C / 105°C|
|Qualcomm||32-bit, Quad core Krait 300 CPU, 1.5GHZ CPU Clock speed|
|Renesas||64 kB Data Flash, 4MB Code Flash, 640kB SRAM, 240MHz||-40°C to 105°C|
|Silicon Labs||32-bit, upto 256kB Flash, 40/48 Mhz|
|ST Micro||32-bit, upto 1MB Flash, 64kB/128kB SRAM, 80 MHz||-40°C to 85°C / 125°C|
|TI||32-bit, upto 256kB Flash, 64kB SRAM||85°C|
Some more analytical points on IoT Microcontrollers
This article is in continuation to other main article
Also read another related article: