Accelerate Embedded Wireless IoT Development with an Out-of-the-Box Embedded Linux Multicore Platform

Advanced industrial, medical, transportation, and agricultural Internet of Things (IoT) applications require more complex embedded system designs. In this case, despite facing tighter schedules and shrinking budgets, developers have no choice but to build their own development boards to meet performance, connectivity and peripheral requirements. Even though off-the-shelf development boards are possible, factors such as performance, power consumption, size, form factor, and functionality limit their applicability.

Author: Stephen Evanczuk

Advanced industrial, medical, transportation, and agricultural Internet of Things (IoT) applications require more complex embedded system designs. In this case, despite facing tighter schedules and shrinking budgets, developers have no choice but to build their own development boards to meet performance, connectivity and peripheral requirements. Even though off-the-shelf development boards are possible, factors such as performance, power consumption, size, form factor, and functionality limit their applicability.

However, in the age of the ubiquity of the Internet of Things and the Industrial Internet of Things (IIoT), even the most efficient custom development teams can be delayed by regional certification requirements for wireless subsystems, slowing delivery and losing market opportunities.

This article will discuss the making and buying of wireless embedded development boards. It then introduces a turnkey development platform from Digi that provides a comprehensive software environment and an optimized hardware platform with pre-certified wireless modules. This article also shows how the kit can be used to help developers deliver more powerful embedded system solutions quickly and easily.

Comparison of self-made and outsourced embedded development boards

With end-user product expectations and market competition pressures, embedded system developers need to deliver more functionality in ever-shrinking time-to-market windows. Users prefer systems that are easier to connect, use, and maintain. As a result, developers face growing challenges in many ways. For wireless connectivity, short-range and long-range wireless solutions come with associated design certification requirements; implementing suitable Display capabilities increases design complexity and cost; ensuring the continued reliability and long-term availability of these systems poses challenges for developers Challenges, they need to find solutions that can withstand harsh conditions and remain usable over the long life cycles commonly found in industrial or medical applications.

For some applications, the appropriate solution relies heavily on a custom design approach to optimize each subsystem to meet the requirements. However, an increasing number of off-the-shelf design solutions provide a platform that can be easily extended to support the unique requirements of various application areas. However, development teams sometimes decide to build a custom solution rather than buy a pre-built system purely from a development cost perspective, calculating that it is cheaper to build a custom design from scratch than to buy an off-the-shelf design.

In fact, development teams will find that other considerations, including wireless certification, availability, maintainability, and other lifecycle issues, add to the overall cost. In a rapidly evolving market, delays in implementing custom designs can further erode market share and revenue timelines, ultimately limiting the profitability of new products.

To address these issues, Digi has introduced the CC-WMX8MN-KIT ConnectCore 8M Nano Development Kit, an efficient alternative to custom development, providing a turnkey platform capable of meeting the performance and cost requirements of various applications (Figure 1 ).

Accelerate Embedded Wireless IoT Development with an Out-of-the-Box Embedded Linux Multicore Platform
Figure 1: Digi’s CC-WMX8MN-KIT ConnectCore 8M Nano development kit provides everything needed to develop connected systems capable of meeting the growing demands of HMI design, audio/video processing, edge computing and machine learning. (Image credit: Digi)

How turnkey solutions meet different functional needs

The Digi CC-WMX8MN-KIT ConnectCore 8M Nano Development Kit provides a comprehensive hardware platform that reduces development time and system time-to-market. Using the kit, developers can easily implement scalable systems to support a variety of applications such as human-machine interface (HMI) design, audio/video processing, edge computing, machine learning, and more. In addition to the Digi ConnectCore 8M Nano development board, the kit includes a dual-band antenna, console port cable and power supply so developers can start creating connected applications right away.

Like Digi’s other CoreConnect development kits, the ConnectCore 8M Nano development kit leverages Digi’s highly integrated system-on-module (SoM) solution. Based on NXP semiconductor‘s i.MX processor family, Digi’s ConnectCore SOM integrates the functions required for typical embedded applications such as multimedia, security, wired connectivity and pre-certified wireless connectivity. Used in conjunction with an extensive software environment, these SoMs simplify the development of embedded systems, allowing product manufacturers to deliver more complex products faster and with less risk than the custom hardware approach typically used.

For the CC-WMX8MN-KIT development kit, Digi SOM combines the capabilities of NXP’s i.MX 8M Nano processors based on quad Arm® Cortex®-A53 and Arm Cortex-M7 cores with up to 8 gigabytes (GB) of flash memory , up to 1GB of low power double data rate (LPDDR) dynamic random access memory (DRAM), and a host of additional subsystems (Figure 2).

Figure 2: Based on NXP’s i.MX 8M Nano multicore processor, the Digi SoM integrates the memory, connectivity options, security, and power management functions required by a typical embedded system design. (Image credit: Digi)

In its subsystem, the SoM integrates Microchip Technology’s CryptoAuthentication family of security devices, complementing the Arm Cortex-A53 core’s TrustZone security capabilities. The CryptoAuthentication device, on the other hand, combines a dedicated cryptographic processor, high-quality random number generator, and protected key storage for high-speed secure execution of hashing and public key infrastructure (PKI) algorithms.

The SoM’s built-in connectivity options support Gigabit Ethernet (GbE) as well as pre-certified 802.11 a/b/g/n/ac Wi-Fi and Bluetooth 5. To meet WAN needs, developers can add cellular connectivity and other connectivity options simply by connecting Digi’s XBEE cellular module to the CC-WMX8MN-KIT board’s XBEE-compatible connector set.

In addition to a full set of standard peripheral interfaces, the SoM supports a variety of multimedia interfaces for audio, cameras and displays. The integrated graphics processing unit and liquid crystal display interface (LCDIF) controller allow developers to easily add optional LCD panels, such as Digi’s CC-ACC-LCDW-10, and quickly start creating HMI designs for their embedded applications.

Power Management in Advanced Processor-Based Designs

Power management of complex embedded systems can be a significant challenge, especially when the system design integrates an advanced processor like NXP’s i.MX 8M Nano. Like other processors in its class, NXP’s i.MX 8M Nano incorporates many different core processors (VDD_ARM and VDD_SOC), GPU (VDD_GPU), memory (VDD_DRAM, NVCC_DRAM), secure non-volatile storage (NVCC_SNVS_1P8, VDD_SNVS_0P8) and many more The subsystems are divided into independent power domains. Not only do developers need to provide each domain with the appropriate power rails, they also need to power up (and power down) each domain with specific timing (Figure 3).

Figure 3: Like most advanced processors, NXP’s i.MX 8M Nan divides its subsystems into separate power domains that require their respective power rails to be turned on with specific timing at startup. (Image credit: NXP Semiconductor)

In fact, Digi’s ConnectCore i.MX 8M Nano SoM requires only two power inputs and uses ROHM Semiconductor’s BD71850MWV Power Management IC (PMIC) to provide multiple supply voltage levels required by i.MX 8M Nano processors and other devices . Designed for NXP-enabled i.MX 8M Nano processors, the ROHM BD71850MWV integrates multiple buck regulators and low dropout (LDO) regulators to provide the complete power rail from the VSYS 5 V main supply (Figure 4) .

Figure 4: The ROHM BD71850MWV PMIC is designed to power the NXP i.MX 8M Nano processor, providing the full set of power rails required for this processor and other devices in a typical embedded system design. (Image credit: ROHM Semiconductor)

While the BD71850MWV manages the detailed power-up and power-down sequences required by the processor, Digi takes it a step further to optimize overall power consumption and maintain system reliability. The Digi Microcontroller Auxiliary (MCA) is integrated in the SoM and uses NXP’s dedicated Kinetis KL17 MKL17Z64VDA4 microcontroller (MCU) for system-level power management. NXP’s Kinetis KL17 MCUs feature an ultra-low-power Arm Cortex-M0+ core that consumes only 46 microamps (μA) per megahertz (MHz) in ultra-low-power run mode, while maintaining memory and real-time clock (RTC) functionality. In stop mode, only 1.68 μA is consumed.

The MCA remains active even when the system is in sleep mode, executing upgradeable firmware running on the KL17 MCU to provide multiple options for waking up NXP’s i.MX 8M Nano system processor. For example, Digi has adopted a default setting to disable the system processor’s RTC in favor of the low-power RTC feature implemented in the MCA firmware. Developers can use the MCA’s 12-bit analog-to-digital converter (ADC) to monitor external events and generate interrupts to wake up the system processor only when needed. In turn, the MCA firmware implements three multi-channel pulse width modulation (PWM) controllers for external operation. To help ensure overall system reliability, the MCA firmware also provides a watchdog timer feature that can prevent the software running on this processor from hanging, or if the software does not perform regular watchdog timer maintenance during normal software execution. This feature resets the entire system or just the system processor.

At system startup, the MCA starts running once power is applied. After a programmable delay, the MCA turns on the BD71850MWV PMIC, which performs the i.MX 8M Nano power-up sequence described earlier. A system reset or transition from a low-power sleep state occurs in much the same way that the MCA coordinates the PMIC and the processor to restore power.

Production-ready embedded Linux software environment

The Digi CC-WMX8MN-KIT Development Kit leverages its extensive hardware base to provide a production-ready software environment running the open source Digi Embedded Yocto (DEY). DEY expands on the Yocto Project’s popular embedded Linux distribution with additional Board Support Package (BSP) capabilities designed specifically to support Digi hardware platforms (Figure 5).

Figure 5: Digi Embedded Yocto extends the base Yocto Project Linux distribution with a Board Support Package (BSP) for Digi hardware. (Image credit: Digi)

In a BSP extension to the Linux kernel, Digi’s TrustFence provides a security framework for Linux devices. Leveraging its authentication and identity management capabilities, TrustFence Service extends from low-level access control of internal and external I/O ports to high-level support for secure network connectivity and secure boot with authenticated firmware images. While not initially supported by the ConnectCore 8M Nano module, Digi TrustZone will be available in a future DEY release.

In addition to security and management at the individual device level, large-scale IoT applications inevitably require the ability to monitor and manage a fleet of IoT devices. To support these requirements, Digi Remote Manager offers a cloud-based service designed to support device health monitoring, configuration management, and firmware updates. Using the mobile app or desktop software, developers can use Digi Remote Manager to display detailed operational information for fleets, including fleet health, alerts, connection status, and signal strength (Figure 6).

Figure 6: The Digi Remote Manager cloud service allows developers to monitor and manage large-scale IoT deployments from their desktop or mobile device. (Image credit: Digi)

In addition to monitoring capabilities, Digi Remote Manager enables developers to more proactively manage data, connectivity and device software using the command line interactively or programmatically using the service’s application programming interface (API). With these capabilities, developers can reboot devices and upload files, making it easy to perform the large-scale device fleet firmware and software updates required for typical interconnected devices, but often with logistical challenges when deploying at scale.


Increasingly complex application requirements in market segments such as industrial, medical, transportation, and agriculture are driving the need for more sophisticated IoT-oriented embedded system designs. Regional certification requirements for associated wireless subsystems also complicate matters and slow down design.

To address these issues, Digi offers a development kit that provides designers with a comprehensive software environment and optimized hardware platform with pre-certified wireless modules. As mentioned above, the kit makes it easier and faster for developers to deliver powerful connected embedded system solutions.

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