IoT is drastically changing how you interact with objects, devices in your home, at work and the world around you. The rapid increase of electronic content and connectivity in automobiles, increasing demands for networking bandwidth, connected industrial and medical electronics, connected homes and the proliferation of smart mobile devices are all driving technology innovation and security leadership at leading industries to help you develop smart, connected solutions. Meeting all the stated requirements requires wireless µController based solutions. Here is an exclusive study by EM Media. Here we go …
Today’s semicons offer a portfolio of low-power, cost effective wireless solutions for embedded devices. These solutions address a number of monitoring and control applications for the internet of Things, including consumer, smart energy, industrial and healthcare. Convenience, security, reliability and power efficiency drive low-frequency RF application requirements. Today’s available wireless microcontrollers help you design cost-effective, highly reliable RF products. Latest wireless technologies enable innovative, scalable and dedicated designs that fit small footprints, consume very little power, and operate in rugged environments—indoors or outdoors. In an increasingly connected world, wireless connectivity is more essential than ever. Consumer’s demands are escalating as wireless extends from PC peripherals and home entertainment applications to the Smart Grid and beyond. To support these sophisticated applications, market players offers a complete line of IEEE 802.15.4-compliant, IPv6/6LoWPAN based, ZigBee certified wireless solutions. To ease development and speed time to market, Atmel offers a variety of free software stacks, reference designs, wireless modules and development kits. Together, Atmel solutions and tools provide everything you need to meet the unique needs of low-cost, low-power, wireless control and sensor network applications. Regulation and lifestyle are driving the change: the need to conserve energy, increase efficiency and use technology to work for us and improve how we live. These trends push connectivity in applications such as:
Wearable devices: smart wrist and arm bands, watches, fitness and healthcare devices
Smart Home: smart lighting, appliances, energy-control and home-security devices
Smart City: smart metering, asset tracking, etc.
Smart Car: connectivity in the car and smart electric-vehicle charging stations
Challenges with designing wireless µProcessors
The biggest challenge by far has been the age old trade-off between efficiency and linearity. To date, despite all of the advances made in area of linearization, we are simply in a situation where we cannot end up with the efficiency of a compressed amplifier when amplifying modulated waveforms with appreciable peak to average ratios at frequencies and bandwidths typically employed for satellite communications. The biggest challenge facing a designer of wireless applications is not necessarily the RF part of the design. That’s what some people call the “Black Magic” portion of wireless devices. The most challenging part of designing a wireless device is definitely programming. The RF circuits in the SynthHD USB-based RF signal generator are serially programmed by an onboard microprocessor that needs to do 64-bit math. There are 15- 32-bit registers that need to be calculated for the RF circuit, plus some D/As for controlling circuit gain. The processor also needs to communicate via USB to a personal computer. Therefore, you can select a 32-bit ARM microcontroller from Freescale.
Speed, range, product design, efficiency and reliability from mobile phones to Wi-Fi and the Internet of Things are key challenges designers face for wireless applications and devices. Multiple use cases with mobile devices continue to develop driving advances in technology. These devices must support a wide range of other services that consumers have become dependent upon such as text messaging, MMS, email, Internet access, short-range wireless communications like Bluetooth and Wi-Fi, business applications, gaming and photography. Wireless application design must adapt to the changing environment. Video streaming has become more popular with applications such as YouTube and video integrated into everything, furthering the demand to deliver high quality video to maximize the user experience. Continuous design improvement is needed in order to limit disruption, improving overall wireless performance. In terms of product design, the demand to have consumer devices maintain a thin, sleek profile has increased, causing the space inside smartphones and devices to decline 25 percent annually. This trend compounds the challenge of finding room for all of the antennas required to support Multiple Input Multiple Output (MIMO) and multiple bands, especially the lower frequencies preferred by operators (700MHz), which require physically larger antennas. LTE devices such as smartphones also need antennas for GPS, Wi-Fi, Bluetooth and NFC, plus 2G/3G fallback. A thin form factor places constraints on the functionality and performance due to wireless capacity limitations. The challenge becomes identifying performance requirements, as well as application usage and connectivity to help determine the volume of the application before designing.
Security requirements are very application dependent, but good off-the-shelf solutions exist for both encryption and authentication. It’s important to consider key management in the whole lifetime of the product through production/programming, initial connection to its network and eventual re-commissioning to a new network.
Designers of wireless applications for the Smart Home are facing a bevy of challenges. How do you make it small enough, how do you make it secure enough and maintenance free, how do you ensure that your new application will communicate with other wireless applications – both those currently available as well as what may appear in the future. How do you create a smart home device that will be successful? To solve these questions, one need to understand what customers really want – what the industry is truly looking for. Many companies today are making the mistake of thinking that simply connecting a device is good enough – it is not. They need to understand that Smart Home customers want services – not just connected devices. They are looking for services that make their live safer, more secure, and more convenient, and more efficient. To be successful, wireless device developers need to create a network of devices, actuators and controllers – often called sentrollers – that incorporates intelligence and the ability to learn. It is no longer enough to be connected, it has to be smart.
Wireless Microcontrollers Enable the Smart Home
With the advent of IPv6, the availability of unique Internet addresses is, for all practical purposes, now limitless. How they are applied, therefore, has yet to be fully defined, but suffice it to say the word ‘smart’ will play a key role. The smart home, for example, presents the ideal environment for addressable nodes; it is entirely likely that every device in the home will become ‘smarter’ in the near future, and that means our homes will be smarter as a result. The idea of managing your home environment from afar is only the beginning. Conceptually you may not even need to manage things in the conventional sense; your home will be able to make its own decisions. This will take the form of intelligent lighting, security systems that recognize individuals or environmental settings that adapt to the season, the time of day and occupancy level. All of this will be possible, thanks to nodes empowered by microcontrollers, communicating predominantly wirelessly over secure channels to gather and exchange data. There are many opportunities for improving the way everyday activities are carried out in the future, which could include secure access. ‘Smart locks’ are now available that can be programmed with individual codes to help the homeowner remain aware of who is in the house and when, for example. The smart home will be enabled by a plethora of sensors, controlled and connected through low cost, ultra-low-power microcontrollers and it represents a massive opportunity for OEMs targeting this exciting and potentially profitable new sector.
Integrated solutions from NXP
While the low-level protocol remains IEEE 802.15.4, the higher levels are numerous and varied, as are the devices that implement them. The JN516x family of wireless microcontrollers from NXP Semiconductors integrates a proprietary 32-bit RISC core alongside a wireless transceiver that comprises a 2.45 GHz radio, a modem, a baseband controller and a security co-processor, as well as a dedicated output for direct control of an external power amplifier if increased range is required. The security co-processor provides hardware-based 128-bit AES-CCM modes as required in the IEEE 802.15.4 2006 standard, while the transceiver block provides both MAC and PHY functionality under the control of a protocol stack running on the CPU, alongside the high-level protocols and application software. While the modem provides all the necessary modulation and spreading functions required for the digital transceiver at 250 kbit/s in compliance with the IEEE 802.15.4 standard, the baseband processor provides all the time-critical functions of the MAC layer, using dedicated hardware to ensure precise timing for the air interface. This hardware/software partitioning allows the software to implement the sequencing of events required by the protocol to schedule timed events with millisecond resolution, while the hardware is able to implement specific events with microsecond timing resolution. Software handles higher-layer features of the protocol, such as sending management and data messages between endpoint and coordinator nodes using the services provided by the baseband processor. The security co-processor can be accessed by the application software to perform encryption/decryption operations. The hardware-based implementation of the encryption engine significantly accelerates the process.
Wireless Microcontrollers and Solutions by Nordic Semiconductor
Sebastien Mackaie- Blanchi (FAE & Customer Engineering Manager – APAC, Nordic Semiconductor
Wireless MCU are becoming more and more popular. The already well-documented reason is that they enable any device to become part of the IoT.
The other main reason is that, outside of IoT, a wireless MCU supporting a wireless standard available in mobile phones/tablets/PCs allows millions of devices (very often simple sensors/actuators) to use the human interface of such phones/tablets/PCs. The success of Bluetooth Smart is directly linked to this fact, and moving from a MCU to a wireless MCU gives access to controlling the device using, for instance, a mobile phone, which can lead to removing any display from the device and thus save cost. It also adds the capability to upgrade the device firmware wirelessly from the phone, possibly removing the need for cables & connectors which is another cost saving. The phone can then be used as a control terminal, removing the need to use a specifically-designed terminal. The main requirement is to support the most common wireless standards. Currently Bluetooth Smart is supported by all recent mobile phones, tablets and PCs, offering a very low current consumption and supporting the IPv6 (6LowPAN) protocol, making this technology a very good fit for devices with low data throughput requirements. Another common wireless technology is Wi-Fi, offering high data throughput but at the cost of a high current consumption. The 802.15.4 radio is another option, running Google Thread for example (6LowPAN-based as well). The next requirement is low current consumption, as many devices using Wireless MCUs are battery-based, sometimes even coin cell-based. It is thus critical to use the right wireless technology and the right wireless MCU to minimize the current consumption and provide an acceptable battery lifetime. The last requirement is for a Wireless MCU to offer as much memory (RAM, Flash), interfaces (SPI, I2C, UART…) and processing power (ARM Cortex-M4 for instance) as non-wireless MCUs do allow a complete replacement of the existing non-wireless MCU. If this requirement is not met, solutions with two chipsets (a MCU and a wireless connectivity chipset) have to be designed, incurring a higher cost and in most cases a higher current consumption.
Wi-Fi and ZigBee are two popular wireless standards but they are not the only ones sharing the 2.4GHz spectrum. Any wireless MCU needs to offer good radio performance to resist interferences from surrounding devices. If a wireless MCU offers multiple protocols, such as Wi-Fi and ZigBee or the more common Wi-Fi/Bluetooth combination, coexistence protocols offer ways to avoid interference by having only one protocol running at a specific time, or by splitting frequencies between protocols.
Wireless protocols have different requirements in terms of memory (some protocol stacks are more complex than others), a multi-protocol wireless MCU must accommodate for multiple protocol stacks being used concurrently.
Nordic Semiconductor has designed a unique protocol stacks architecture which separates the protocol stacks from the main application, allowing for easy replacement (for instance through Over The Air update) of either the protocol stack, the application or both.
Another major requirement of modern architecture design is “Low power and Small footprints”. Low power is driven by two factors: the wireless standard being used and the radio performance. The wireless standard is the key factor. Some wireless protocols offer less current consumption since they have been designed for that goal. The critical factor is to find the best low-power protocol that fits the product specification, which is driven by the data throughput required by the product. Small footprint: The chipset must be as small as possible in size to allow for a small design. This is achieved by using a modern node manufacturing process (such as 55nm), which allows complex wireless MCUs to fit into 6x6mm QFN packages, or smaller 3x3mm chip scale packages (like Nordic Semiconductor’s nRF52 series chipsets).
Nordic Semiconductor offers multiple System-on-chip solutions. nRF51 series and nRF52 series are the latest products, both supporting multiple 2.4GHz protocols that can be used concurrently: Bluetooth Smart, ANT and proprietary protocols. Both series support a large choice of interfaces (UART, SPI, I2C, ADCs, GPIOs, and even audio interfaces such as PDM and I2S for nRF52 series). nRF51 series are SoCs with ARM Cortex-M0 processor @16Mhz, up to 256KB of embedded Flash and 32KB of RAM. nRF52 series are SoCs with ARM Cortex-M4 processor @64MHz, currently 512KB of embedded Flash and 64KB of RAM.
