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How does LoRa Benefit IoT?

Cycleo, a part of Semtech since 2012, has developed and patented a physical layer with a modulation type, with the name LoRA or Long Range, where the transmission utilizes the license-free ISM bands. LoRa consumes very low power and is therefore, ideal for IoT for data transmission. Sensor technology is one possible field of application for LoRa, where low bit rates are sufficient, and where the sensor batteries last for months or even years. Other applications are in the industry, environment technology, logistics, smart cities, agriculture, consumption recording, smart homes, and many others.

LoRa uses wireless transmission technology, and consumes very low power to transmit small amounts of data over distances of nearly 15 Km. It uses CSS or Chirp Spread Spectrum modulation, originally meant for radar applications, and developed in the 1940s, with chirp standing for Compressed High Intensity Radar Pulse. The name suggests the manner of data transmission by this method.

Many current wireless data transmission applications use the LoRa method, owing to its relative low power consumption, and its robustness against fading, in-band spurious emissions, and Doppler effect. IEEE has taken up the CSS PHY as a standard 802.15.4a for use as low-rate wireless personal area networks.

A correlation mechanism, based on band spreading methods, makes it possible for LoRa to achieve the long ranges. This mechanism permits use of extremely small signals that can disappear in noise. De-spreading allows modulation of these small signals in the transmitter. LoRa receivers are sensitive enough to decode these signals, even when they are more than 19 dB below the noise levels. Unlike the DSSS or direct sequence spread spectrum that the UMTS or WLAN uses, CSS makes use of chirp pulses for frequency spreading rather than using the pseudo-random code sequences.

A chirp pulse, modulated by GFSK or FM, usually has a sine-wave signal characteristic along with a constant envelope. As time passes, this characteristic falls or rises continuously in frequency. That makes the frequency bandwidth of the pulse equivalent to the spectral bandwidth of the signal. CSS uses the signal characteristic as a transmit pulse.

Engineers use LoRaWAN to define the MAC or media access protocol and the architecture of the system for a WAN or wide area network. The special design of LoRaWAN especially targets IoT devices requiring energy efficiency and high transmission range. Additionally, the protocol makes it easier for communications with server-based internet applications.

The architecture of the LoRaWAN MAC is suitable for LoRa devices, because of its influence on their battery life, the network capacity, the service quality, and the level of security it offers. Additionally, it has a number of applications as well.

The LoRa Alliance, a standardization body, defines, develops, and manages the regional factors and the LoRa waveform in the LoRaWAN stack for interaction between the LoRa MAC. The standardization body consists of software companies, semiconductor companies, manufacturers of wireless modules and sensors, mobile network operators, testing institutions, and IT companies, all working towards a harmonized standard for LoRaWAN. Using the wireless technology of LoRa, users can create wireless networks covering an area of several square kilometer using only one single radio cell.

Why Use a Multi-Layer PCB?

Although a multi-layer PCB is more expensive than a single or double-layer board of the same size, the former offers several benefits. For a given circuit complexity, the multi-layer PCB has a much smaller size as compared to that a designer can achieve with a single or even a double-layer board—helping to offset the higher cost—with the main advantage being the higher assembly density the multiple layers offer.

There are other benefits of a multi-layer PCB as well, such as increased flexibility through reduced need for interconnection wiring harnesses, and improved EMI shielding with careful placements of layers for ground and power. It is easier to control impedance features in multi-layer PCBs meant for high-frequency circuits, where cross talk and skin effect is more prominent and critical.

As a result, one can find equipment with multi-layer PCBs in nearly all major industries, including home appliances, communication, commercial, industrial, aerospace, underwater, and military applications. Although rigid multi-layer PCBs are popular, flexible types are also available, and they offer additional benefits over their rigid counterparts—lower weight, higher flexibility, ability to withstand harsh environments, and more. Additionally, rigid flex multi-layer PCBs are also available, offering the benefits of both types in the same PCB.

Advantages of a Multi-Layer PCB

Compared to single or double-layer boards, multi-layer PCBs offer pronounced advantages, such as:

Higher Routing Density
Compact Size
Lower Overall Weight
Improved Design Functionality

Use of multiple layers in PCBs is advantageous as they increase the surface area available to the designer, without the associated increase in the physical size of the board. Consequently, the designer has additional freedom to include more components within a given area of the PCB and route the interconnecting traces with better control over their impedance. This not only produces higher routing density, but also reduces the overall size of the board, resulting in lower overall weight of the device, and improving its design functionality.

The method of construction of multi-layer PCBs makes them more durable compared to single and double-layer boards. Burying the copper traces deep within multiple layers allows them to withstand adverse environment much better. This makes boards with multiple layers a better choice for industrial applications that regularly undergo rough handling.

With the availability of increasingly smaller electronic components, there is a tendency towards device miniaturization, and the use of multi-layer PCBs augments this trend by providing a more comprehensive solution than single or double-layer PCBs can. As these trends are irreversible, more OEMs are increasingly using multi-layer boards in their equipment.

With the several advantages of multiple layer PCBs, it is imperative to know their disadvantages as well. Repairing PCBs with several layers is extremely difficult as several copper traces are inaccessible. Therefore, the failure of a multi-layer circuit board may turn out to be an expensive burden, sometimes necessitating a total replacement.

PCB manufacturers are improving their processes to overcome the increase in inputs and to reduce design and production times for decreasing the overall costs in producing multi-layer PCBs. With improved production techniques and better machinery, they have improved the quality of multi-layer PCBs substantially, offering better balance between size and functionality.

What are Multi-Layer PCBs?

Most electronic equipment have one or more Printed Circuit Boards (PCB) with components mounted on them. The wiring to and from these PCBs determines the basic functionality of the equipment. It is usual to expect a complex PCB within equipment meant to deliver highly involved performance. While a single layer PCB is adequate for simple equipment such as a voltage stabilizer, an audio amplifier may require a PCB with two layers. Equipment with more complicated specifications such as a modem or a computer requires PCB with multiple layers, that is, a PCB with more than two layers.

Construction of a Multi-Layer PCB

Multiple layer PCBs have three or more layers of conductive copper foil separated by layers of insulation, also called laminate or prepreg. However, a simple visual inspection of a PCB may not imply its multi-layer structure, as only the two outermost copper layers are available for external connection, with the inner copper layers remaining hidden inside. Fabricators usually transform the copper layers into thin traces according to the predefined electrical circuit. However, some of the layers may also represent a ground or power connection with a large and continuous copper area. The fabricator makes electrical interconnections between the various copper layers using plated through holes. These are tiny holes drilled through the copper and insulation layers and electroplated to make them electrically conducting.

A via connecting the outermost copper layers and some or all of the inner layers is a through via, that connecting one of the outermost layers to one or more inner layers is the blind via, while the one connecting two or more inner layers but not visible on the outermost layers is the blind via. Fabricators drill exceptionally small diameter holes using lasers to make vias, as this allows maximizing the area available for routing the traces.

As odd number of layers can be a cause of warping in PCBs, manufacturers prefer to make multiple layer boards with even number of layers. The core of a PCB is an insulating laminate layer with copper foils pasted on both its sides—forming the basic construction of a double-layer board. Fabricators make up further layers by adding a combination of prepreg insulation and copper layers on each side of the double-layer board—repeating the process for as many extra layers as defined by the design—to make a multi-layer PCB.

Depending on the electrical circuit, the designer has to define the layout of traces on each copper layer of the board, and the placement of individual vias, preferably using CAD software packages. The designer transfers the layered design output onto photographic films, which the fabricator utilizes to remove the excess metal from individual copper layers by the process of chemical etching, followed by drilling necessary holes and electroplating them to form vias. As they complete etching and drilling for each layer, the fabricator adds it on to the proper side of the multi-layer board.

Once the fabricator has placed all layers properly atop each other, application of heat and external pressure to the combination makes the insulation layers melt and bond to form a single multi-layer PCB.

How do Surge Trap SPDs Work?

Surge trap Surge Protection Devices or SPDs are protection devices to absorb high-energy power spikes that could damage sensitive electronic equipment such as process controllers, instrumentation, and computers. They divert high-energy power away from an appliance by providing a low-impedance path to the common point earth ground. Frequently, panel boards use several metal oxide varistors or MOVs, connected in parallel, to act as surge suppressors or traps.

AC surge suppressors most commonly use an MOV comprising solid-state zinc oxide having multiple junctions. When conducting, MOVs offer a low impedance path, and come in packages for specific voltage and current handling capacities. Surge suppression devices found in DC applications mostly are single junction diodes and/or gas discharge tubes that ionize at preset voltages.

Installation of most AC surge traps are typically at the entrance to a utility service for protecting the entire facility, in distribution switchboards and panel boards for the protection of sensitive loads downstream, and/or in wall outlets for protecting an individual and specific piece of equipment such as a solid-state controller or a computer.

NEMA standards define the surge current capacity of a surge trap as the maximum level of current it can withstand for single transient event. The level indicates the protection capacity of the surge suppressor.

The suppressed voltage rating (SVR) or the clamping voltage of a surge trap is the voltage it permits passing on to the attached load during a transient event. The ability of the surge trap to attenuate a transient is its performance measurement and the clamping voltage provides this. The Underwriters Laboratories or UL confirms the clamping voltage during tests it conducts while evaluating surge traps.

The short circuit rating and the surge current capacity of a surge trap are the criteria a user should consider while selecting a device for its performance and safety. The user should make sure the surge device they have selected is not fuse limited, as many manufacturers use fuse limiting in front of the device for passing UL testing conditions.

Installing a surge trap SPD is always in parallel with the load. The surge trap SPD remains idle and does not conduct when the operating voltage is within the normal levels. The SPD turns on whenever the system experiences an overvoltage and conducts the extra current to the ground, while allowing the load to experience the correct voltage. The performance of a pressure relief valve in a steam system offers an operational similarity.

It is easy to retrofit an existing panel with a surge trap SPD, provided the panel has adequate space. Typical control panels in industries have a mains disconnect feeding a power distribution block, which then connects to individual loads. Users can mount the surge trap SPDs on the standard 35-mm DIN-rail that the panels typically use.

Manufacturers recommend mounting surge trap SPDs as close as possible to the power distribution block with #8-#14 AWG wires, not exceeding a length of 20 inches. Users must make sure of not twisting any wires together, and of not forming any loops, as these can result in higher voltages that the SPD let through.

Ethoscope with the Raspberry Pi

Although ethoscopes are very popular instruments for detecting or recording the real-time activity of fruit flies, they can potentially be used on other animals as well. The ethoscope platform is actually a collection of interconnected tools that biologists use when designing experiments, to capture and analyze huge amounts of behavioral data.

The ethoscope uses a free and open-source set of tools, both hardware and software. The hardware is a Raspberry Pi (RBPi) while the software is built on top of GNU/Linux and Python. The RBPi also has some custom printed parts.

The ethoscope is capable of real-time video tracking, allowing experimenters to deliver individual stimuli based on the behavior of the animal the biologist is tracking. Simultaneous and effective control of several devices is possible with a modern web-interface. The software package rethomics offers high-throughput and detailed post-hock analysis. The modular design of the ethoscope is straightforward enough to modify both the software and the device, thereby creating new paradigms for experiments. The RBPi based ethoscope is highly scalable and biologists can run multiple and inexpensive ethoscopes in parallel on the same platform.

Using computerized video tracking, the ethoscope uses as its base the small single-board computer, the RBPi, along with a high-definition camera to capture and process in infrared the video with a resolution of 1920×1080 pixels, at 30 frames per second.

Assembling ethoscopes requires a 3-D printed chassis with cables. This produces a footprint of approximately 10x13x20 cm. Although research grade ethoscopes need the 3-D printed chassis, those who simply want to try out can build a fully functional chassis from LEGO bricks or even from folded cardboard, following detailed instructions on the ethoscope website. The LEGOscope or the PAPERscope require only minor technical skills, and are therefore suitable for assembling ethoscope for education and outreach.

Although an RBPi will not help in performing complex brain surgeries, it does help scientists in working out how our minds work. That led researchers to select the low-cost single board computer for conducting experiments and studying neuroscience. The RBPi has the potential to be a machine the scientists use for making groundbreaking discoveries about the mannerisms of the human behavior.

In the Imperial College of London, Dr. Giorgio Gilestro and colleagues first used the RBPi to create the ethoscope. They designed the device to track animal behavior with open-source hardware and software. However, it has a profile for using machine-learning algorithms.

As fruit flies are similar to humans in behavioral and genetic terms, Dr. Giorgio used them for the primary studies. According to the researchers, they can use the ethoscope for studying mental and physical diseases in humans, and the instrument can provide insights into behaviors such as socializing and sleeping.

Earlier, the scientists could only watch the flies manually and score their movements. However, the addition of the RBPi has enhanced the features of the ethoscope and now they can record, process and analyze real-time video, thereby automating the time-consuming process. As the ethoscopes are small, cheap, and easy to maintain, the scientists can study hundreds of flies simultaneously. The RBPis give them enough computer power for analyzing behavior using video imaging.

Do It Yourself Blynk Board

Those who have some experience with Do It Yourself (DIY) electronic projects, and are just starting to test the waters in the Internet of Things (IoT), the Blynk Board from SparkFun is an activity filled challenging exercise. Both experienced users as well as beginners will find this fun to set up and learn—the kit comes with more than ten projects.

Of course, you can make this board work without the IoT Starter Kit from SparkFun, but then you will have to buy the sensors and other components separately to complete the projects. The Blynk Board, based on the ESP8266, runs on a 32-bit L106, a RISC microprocessor core running at a speed of 80 MHz. It has 1 MiB flash built-in, and allows single-chip devices to connect with Wi-Fi, IEEE 802.11 b/g/n. The board has the TR switch integrated, LNA, balun, power amplifier, matching network WPA/WPA2 or WEP authentication, and can connect to open networks. Other features include 16 GPIO pins, I2C, SPI, I2S, UART with dedicated pins, and a UART (transmit-only) capable of being enabled from GPI02. The board also has a 10-bit successive approximation ADC.

Blynk Boards, based on the ESP8266, come preloaded with projects that are ideal for those just beginning on the Internet of Things and concepts of basic electronics. Arduino boards used it originally for implementing Wi-Fi enabled hardware projects; the ESP8266 has built-in Wi-Fi, making it a cheap, Arduino-compatible, and standalone development board. Many other kits use this board in different shapes and sizes, and you will find it in SparkFun ESP8266 Thing, Adafruit HUZZAH, and NodeMcu.

As the ESP8266 is useful as an open source hardware, it is a useful device for starting with the Internet of Things. It makes the Blynk Board an ideal platform for controlling single board computers such as the Raspberry Pi, and Arduino. Basically, the Blynk consists of three components—a Blynk app for smartphones, the Blynk library, and the Blynk server. The library is compatible with a large number of maker hardware.

While the Blynk library and Blynk server are open source, anyone can use the Blynk app on iOS and Android smartphones. With the Blynk app, you can build a graphical interface for any IoT project—simply drag and drop the widgets. Blynk offers several widgets such as LC display, buttons, and joystick, with which you can start hacking and you need only an IoT development board.

After collaborating with SparkFun, Blynk created the ESP8266 based SparkFun Blynk Board. They offer it fully programmed for more than ten Blynk projects. That makes the IoT Starter Kit from SparkFun with the Blynk Board such a fun project, offering a wonderful introduction to the Internet of Things technology and you do not have to learn any difficult programming.

For those who already have other ESP8266 development boards, simply reprogramming them with the firmware will turn them into DIY Blink Boards. With these, you can easily run boot camps or conduct workshops. Just adding the sensors and a few other components will help you complete the built-in projects, and these you can buy from SparkFun.

A New Magnet for Electric Cars

The advent of electric cars is spawning innovations in almost every technology field including batteries, motors, wires, PCBs, electronics, and many more. Electric cars require powerful and efficient motors, and for that, magnets used in the motors must be stronger than usual.

Toyota Motor Corporation has developed a new magnet for electric motors, and they have reduced by 50% the use of critical rare-earth elements they were using so far. As the number of electric cars is set to increase rapidly in the future, Toyota is expecting this heat-resistant magnet, which uses less neodymium, will find increasing use in the electrified vehicles.

Neodymium, terbium, and dysprosium are rare-earth elements that industries popularly use when manufacturing strong magnets. Although the magnets made from these elements can operate in high-temperature conditions, they are expensive. Toyota has replaced a proportion of the neodymium in these magnets with lanthanum and cerium, as these are low-cost rare earth elements.

Manufacturers of magnets use neodymium as it provides their products with high heat resistance and coercivity—the ability to maintain magnetism at high temperatures. However, simply using less neodymium and using lanthanum and cerium instead would cause the motor to underperform. Therefore, Toyota had to adopt newer technologies to overcome the deterioration in motor performance. The result was a successful magnet with half the amount of neodymium, but equivalent levels of heat resistance and coercivity.

Toyota expects this new magnet to maintain a balance between the supply and demand of resources especially that of the valuable rare earth elements, while being useful in the expanding world of electric automobiles and robotics. Toyota is continuing in its efforts to enhance the performance further, and evaluate the use of the magnet in a greater number of products. They are also aiming to accelerate the development of technologies for mass-producing the magnets, so that different products can adopt them easily, including robots and vehicles.

Use of rare earth elements in magnets enables them to maintain magnetism even at high temperatures. For this, they require about 30% of the elements in the magnets to be of the rare earth types.

Adding neodymium in magnets makes them more powerful, but automotive applications require them to operate at high temperatures. Although adding terbium and dysprosium improves the high-temperature coercivity, it also makes the magnets more expensive. Toyota’s efforts at creating cheaper magnets with reduced use of neodymium have finally paid off.

Although at present, the production volumes of neodymium are adequate there are concerns that as the development of electrified vehicles picks up, the demand will outstrip supply. This is may become a bigger concern as electrified vehicles include hybrid electric as well as battery powered electric vehicles of all types are likely to become more popular in the future.

Toshiba uses three new technologies in their magnets to help maintain coercivity at high temperatures, even with reduced neodymium. For this, they had to refine the grains in the magnet, use two-layers of high-performance grain surfaces, and use an alloy with a specific ratio of lanthanum and cerium.

Things Gateway Ties IoT Devices Together

Project Things from Mozilla is a framework of software and services. It helps to bridge the communication gap between IoT devices. Project Things does this by giving each IoT device a URL on the web. The latest version of the Things Gateway, also from Mozilla, can directly let you control your home over the web, and manage all your devices through a single secure web interface. Therefore, if you have several smart devices in your home, you will not need different mobile apps to manage each of them. The best part of the Things Gateway is you can easily build one on a single board computer and use the power of the open web to connect off-the-shelf smart home products immediately, even if they are from different brands.

DIY hackers will find many exciting new features in the latest version. It even includes a rules engine, where you can set ‘if this, then that’ style of scenarios for making up rules of how things should interact. Other features include a floor plan view for laying out the devices on a map of your house, an experimental voice control, and it supports several new types of IoT devices. If you have a new device requiring new protocols, there is a brand new add-ons system. Third party applications that want to access your gateway can now do so, as there is a new way to authorize them safely.

On the hardware side, you will need a single board computer. Although Mozilla recommends a Raspberry Pi 3, any single board computer will do, as long as it has Wi-Fi and Bluetooth support built-in. Access to GPIO ports is also necessary, as you will require direct hardware access. Although a laptop or desktop computer will also work here, using the single board computer will provide the best experience.

If your smart home devices use other protocols such as Zigbee or Z-Wave, you will also need a USB dongle. Things Gateway supports Zigbee with Digi Xstick and for Z-Wave you will have to use a dongle compatible with OpenWave. You will need the proper device suitable for your region, as Z-Wave operating frequencies vary for different countries.

For the software part, you will need at least a 4 GB micro SD card to flash the software. The Gateway already has support for several different smart sensors, plugs, and smart bulbs from various brands, which may be using Wi-Fi, Z-Wave, or Zigbee. The Wiki mentions all the tested parts, and you can contribute if you have tested other new devices. However, if you are not yet ready with the actual hardware of IoT devices, and want to try out the Gateway software, the Virtual Things add-on us your friend. Simply install it and start adding virtual IoT things to your Gateway.

Mozilla offers the Things Gateway software image for the Raspberry Pi, which you can download and flash onto the micro SD card. The safest way to do this is to use Etcher, a cross-platform image writer software, useful for Linux, Windows, and the Mac OS.

Raspberry Pi Makes the Pac-Man Game Go 3D

Some avid gamers of today are not even aware of the video games that flourished in the seventies and the eighties. Those who have a collection of retro games may have given their children time to catch up with the old games. One such classic game from the 1980s, a very addictive one, was the pellet-guzzling arcade game with the name of Pac-Man, from Namco. One of the youngsters, Emanuele Coletta, has come up with a 3-D rendition of Pac-Man.

Emanuele wanted to make something funny, while at the same time learn and apply new technology. He decided to add new twist to the project. Therefore, his 3D-printed robots of the main character and the four ghosts, while replacing the dots in the maze of the original game with lights that turn off as the yellow chomper moved over them.

When playing the video game as a single player, Pac-Man must consume all the Pac-Dots, at the same time avoiding the ghosts, as they each move automatically. However, the 3-D Pac Robot Man works differently. Here, four players each control one of the ghosts. The main character, the Pac-Man, now has to escape from the others without being caught, while the others try to catch it. Therefore, this new 3-D Pac Robot Man is a five-player game.

Emanuele and his partners made the playing board from wood. They laser-cut the various pieces and formed the maze. A number of small boards with LEDs and reed switches then went under the gaming field, and they connected these to an Arduino Mini.

The five characters each had an Arduino Uno board underneath, with the main character holding a magnet under it. They connected each robot to 3d-printed joysticks and an Arduino Nano, which allowed the robots to be moved around in the maze. Each joystick communicates with its robot via radio frequencies at 2.4 GHz.

The Arduino Mini communicates with the Raspberry Pi (RBPi), informing it as the main character moves. The Arduino Mini also knows which reed switch the main character has activated, so it switches off the appropriate LED. Each LED the main character ‘eats’ represents points, an all such information, along with the state of the game, reaches the RBPi.

The RBPi projects the scores and the state of the game on a monitor screen, so all players can keep track. Emanuele says he used and open source library named RXTX and the tutorial Arduino Playground to establish a serial communication between the RBPi and the Arduino. The RBPi also plays the original sounds of the game, which give the whole arrangement a sense of being real. The players challenge each other—whoever is able to catch the main character, wins. If the main character escapes by ‘eating’ all the dots, the main character wins.

Pac-Man was one of the most recognized icons in gaming. The game basically involves eating dots, and amassing points, while avoiding four ghosts—Clyde, Pinky, Inky, and Blinky. With the effort Emanuele and his partners have put in, it has revived one of the most addictive games and turned it into a 3-D marvel.

LTM2893 μModule isolator for ADCs

Analog to digital converters (ADCs) need to float to the common mode of the input signal to absorb the harsh voltage conditions and transients. The best way to do this is to place an isolation barrier between the ADC and the external signal. Even applications that perform under moderate conditions can benefit from the presence of an isolator. The LTM2893 from Linear Technology provides such isolation, improving on system safety, especially when reading from high-resolution successive approximation register type of ADCs.

Ideally, the isolator for an ADC should be near invisible. Its function would be to manage the control and data signals, maximizing the sampling rate, and minimizing the effects of jitter on the performance of signal to noise ratio. The LTM2893 μModule isolator from Linear Technology meets all the above criteria, achieving these for ADCs with SPI interfaces, offers a 1 Msps range, while supporting a 6K Vrms isolation rating.

Options that are more traditional exist, but provide limited functionality, especially when reading data from high-resolution successive approximation register (SAR) ADCs. Most traditional high speed digital isolators work maximum up to 25 MHz, with a few special devices reaching 40 MHz On the other hand, the LTM2893 can easily read data samples at rates up to 100 MHz. Additionally, it is flexible enough to be able to handle multiple ADCs. This effectively solves timing issues and other limitations of the standard digital isolator interfacing that SAR ADCs face.

Test and process equipment need isolation so that their inputs are not damaged if accidentally misconnected or from overvoltage events. Usually, engineers use an isolator as a high voltage level shifter for extending the common mode range thereby reducing the ground noise. The LTM2893 is intelligent enough to ignore transients events of the common mode type up to 50K V/μs, as this provides a low-capacitance isolation barrier along with fully differential data communication.

When dedicated SPI isolators and other general-purpose digital isolators isolate ADCs, they use multiple digital isolators for supporting signals such as busy status or conversion start signals. In addition, they offer a 3- or 4-wire SPI port. They also suffer from signal propagation delays, as the isolated SPI port must wait for the return of the acknowledgement signal before the next data latching can occur. Adding all the propagation and the response delays from the ADC SPI port, a single read may suffer a delay of about 35 ns. Therefore, although the initially rating of a digital isolator may be at 150 Mbps, in reality, the delays reduce the effective frequency to 25 MHz or even less.

Linear Technology has provided the LTM2893 with a dedicated master SPI engine on its isolated side, and a dedicated slave engine and a buffer on the logic side. The master SPI engine of the LTM2893 monitors the status signals from the ADC, fetching the data as soon as its BUSY signal goes low. There is no interaction with the logic side once the conversion has started.

The buffer register on the slave SPI engine on the logic side receives data from the isolated side via the isolated barrier. The two sides therefore, operate independently of each other.