Exploring the ESP32’s Peripheral Blocks

For IoT or Home Control

What makes an embedded processor suitable as an IoT or home control device? Wi-Fi support is just part of the picture. Brian has done some Wi-Fi projects using the ESP32, so here he shares his insights about the peripherals on the ESP32 and why they’re so powerful.

By Brian Millier

If you’re interested in IoT or home control devices, you’ve undoubtedly run across Espressif’s ESP8266. The embedded processor became ubiquitous in a very short time. The successor to the ESP8266 is the ESP32 and it’s much more powerful. Like the ESP8266, the ESP32 has on chip Wi-Fi. But it also includes Bluetooth Low Energy (BLE) and sports two high-power cores in place of the single one found on the ESP8266.

Having two main cores means one can run the wireless protocol stack on one core, leaving the other core free for the user application program. In fact, Espressif labels the cores “App” and “Pro”, with the latter referring to the Wi-Fi Protocol stack. This feature allows the application program to run without having to worry too much about how much execution time will be needed to handle the incoming/outgoing Wi-Fi data stream (which is hard to reliably predict, due to its asynchronous nature).

However, in addition to the dual cores, the ESP32 is also blessed with many unique peripheral blocks—most of which operate at a high level and thus require little or no MCU intervention during normal operation. This makes it much easier to write code for projects that have time-critical I/O operations. To appreciate the versatility of the ESP32’s peripheral function blocks, you have to dig into its Technical Reference Manual (TRM). At less than 600 pages, the ESP32’s TRM is somewhat leaner than most new 32-bit MCUs, so I didn’t mind studying it.

The ESP32 has been integrated into the Arduino IDE, and therefore Arduino
Wi-Fi, webserver, web client and UDP client libraries are available. I’ve done a few ESP32 Wi-Fi projects using these libraries, and found them to be straightforward. With all that in mind, in this article I am going to concentrate on three peripheral blocks that I consider to be very powerful and useful. I’ll present some code examples and custom libraries that I have written that make use of these peripherals—sometimes in ways that are different from their intended use).

The three peripheral blocks that I’ll be covering are:

  1. The Remote Control peripheral
  2. The Pulse Counter peripheral
  3. The LEDC controller peripheral

I’ll also briefly discuss the I2S and DAC/Cosine Generator blocks and provide some routines that enable you to generate some useful signals using these blocks.
The most serious work being done with the ESP32 centers on Espressif’s own IDF/C toolchain. But many people prefer to use the Arduino libraries developed for the ESP32, because they are accustomed to using it with many different MCUs—like AVR, ARM and ESP8266/32. Personally, I use the Visual Micro add-in to Visual Studio. It provides a much more professional development environment, while still using the Arduino tool-chain “under the hood.” All references to library files/folders or sample programs can be found on Circuit Cellar’s article materials webpage.

Figure 1
This is a simplified block diagram of the ESP32 Remote Controller peripheral.


Remote Controller Peripheral

This peripheral is rather unique among the MCUs that I have encountered. Its function is twofold:

  1. Transmitting IR signals such as used by IR remote controls
  2. Receiving IR signals from IR remote controls

IR remotes don’t send data in the same way that UARTs, SPI and I2C ports do. In other words, they don’t structure the data with each bit taking a specific amount of time. Instead, a “1” bit will consist of a burst of IR light for a specific time, followed by a specific period of no light. A “0” bit will define different periods of time for either the IR pulse, the space or sometimes both. To complicate matters, the IR light pulses are always amplitude modulated by some carrier frequency (in the 25-60 kHz range)..

Read the full article in the March 332 issue of Circuit Cellar

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Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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You’ll get your IoT Technology Focus newsletter issue tomorrow.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(2/27 Wednesday) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (3/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (3/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

March Circuit Cellar: Sneak Preview

The March issue of Circuit Cellar magazine is coming soon. And we’ve got a healthy serving of embedded electronics articles for you. Here’s a sneak peak.

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Here’s a sneak preview of March 2018 Circuit Cellar:

TECHNOLOGY FOR THE INTERNET-OF-THINGS

IoT: From Device to Gateway
The Internet of Things (IoT) is one of the most dynamic areas of embedded systems design today. This feature focuses on the technologies and products from edge IoT devices up to IoT gateways. Circuit Cellar Chief Editor Jeff Child examines the wireless technologies, sensors, edge devices and IoT gateway technologies at the center of this phenomenon.

Texting and IoT Embedded Devices
Texting has become a huge part of our daily lives. But can texting be leveraged for use in IoT Wi-Fi devices? Jeff Bachiochi lays the groundwork for describing a project that will involve texting. In this part, he gets into out the details for getting started with a look at Espressif System’s ESP8266EX SoC.

Exploring the ESP32’s Peripheral Blocks
What makes an embedded processor suitable as an IoT or home control device? Wi-Fi support is just part of the picture. Brian Millier has done some Wi-Fi projects using the ESP32, so here he shares his insights about the peripherals on the ESP32 and why they’re so powerful.

MICROCONTROLLERS HERE, THERE & EVERYWHERE

Designing a Home Cleaning Robot (Part 4)
In this final part of his four-part article series about building a home cleaning robot, Nishant Mittal discusses the firmware part of the system and gets into the system’s actual operation. The robot is based on Cypress Semiconductor’s PSoC microcontroller.

Apartment Entry System Uses PIC32
Learn how a Cornell undergraduate built a system that enables an apartment resident to enter when keys are lost or to grant access to a guest when there’s no one home. The system consists of a microphone connected to a Microchip PIC32 MCU that controls a push solenoid to actuate the unlock button.

Posture Corrector Leverages Bluetooth
Learn how these Cornell students built a posture corrector that helps remind you to sit up straight. Using vibration and visual cues, this wearable device is paired with a phone app and makes use of Bluetooth and Microchip PIC32 technology.

INTERACTING WITH THE ANALOG WORLD

Product Focus: ADCs and DACs
Makers of analog ICs are constantly evolving their DAC and ADC chips pushing the barriers of resolution and speeds. This new Product Focus section updates readers on this technology and provides a product album of representative ADC and DAC products.

Stepper Motor Waveforms
Using inexpensive microcontrollers, motor drivers, stepper motors and other hardware, columnist Ed Nisley built himself a Computer Numeric Control (CNC) machines. In this article Ed examines how the CNC’s stepper motors perform, then pushes one well beyond its normal limits.

Measuring Acceleration
Sensors are a fundamental part of what make smart machines smart. And accelerometers are one of the most important of these. In this article, George Novacek examines the principles behind accelerometers and how the technology works.

SOFTWARE TOOLS AND PROTOTYPING

Trace and Code Coverage Tools
Today it’s not uncommon for embedded devices to have millions of lines of software code. Trace and code coverage tools have kept pace with these demands making it easier for embedded developers to analyze, debug and verify complex embedded software. Circuit Cellar Chief Editor Jeff Child explores the latest technology trends and product developments in trace and code coverage tools.

Manual Pick-n-Place Assembly Helper
Prototyping embedded systems is an important part of the development cycle. In this article, Colin O’Flynn presents an open-source tool that helps you assemble prototype devices by making the placement process even easier.

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (2/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(2/27) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Analog & Power. (3/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Tuesday’s Newsletter: Analog & Power

Coming to your inbox tomorrow: Circuit Cellar’s Analog & Power newsletter. Tomorrow’s newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Microcontroller Watch. (2/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (2/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(2/27 Wednesday) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

 

Money Sorting Machines (Part 3)

Bill Validation

In this final article of his money sorting machine series, Jeff wraps up his coin sorting project and examines how a bill validator can tell one bill’s denomination from another.

By Jeff Bachiochi

Most of us connect Ben Franklin with kites and lightning. He was also a printer and might be best known for Poor Richard’s Almanack—a yearly publication that he published from 1732 to 1758 under the pseudonym of Richard Saunders. It was a best-seller and thanks to his wit and wisdom, his portrait was added to the cover of The Old Farmer’s Almanac in 1851—appearing opposite the founder Robert B. Thomas. It remains there today.

As a master printer and engraver, in 1730 Franklin began printing all paper money issued by Pennsylvania, New Jersey and Delaware. Paper money was first introduced in the region in 1723, but it remained a hot political issue. That’s because it helped farmers and tradesmen, while merchants and landowners wanted it eliminated or limited in its circulation. Paper money printed from ordinary type was easy to counterfeit, but Ben’s ingenuity solved that problem by printing pictures of leaves on every piece of money. Counterfeiters could not duplicate—or even imitate—the fine lines and irregular patterns. The process by which he made the printing plates was secret, but were probably cast in type metal from molds made by pressing leaves into plaster of Paris. There began the Feds vigilant effort to thwart counterfeiters.

Today every aspect of our paper currency is controlled—from its design to its printing, as well as its monitoring and destruction. The paper (which is not paper) and ink (multiple types and formulas) are fabricated for the express use by the Department of Engraving. That department is the Treasury bureau responsible for paper money—as opposed to the U.S Mint, which is the Treasury bureau responsible for coinage. US currency consists of 25% linen and 75% cotton and contains small randomly disbursed red and blue security fibers embedded throughout the material. Depending on the denomination the material is further enhanced by embedding security threads, ribbons and watermarks. Since 1996, printing with colored and color changing inks make the new currency pop. While older black and green currency is rather drab in comparison, it is still legal tender and remains the target of most counterfeiters.

The previous two parts of this article series (December 329 and January 330) centered around coinage. Before we look at bill validation for paper money, I need to finish up with that project. I had purchased a few Coin Acceptors and showed how they are used to identify coinage, especially but not limited to US coins. The acceptance and dispensing of money is presently used in many ways today, including vending machines and ATMs. The discussion also included National Automatic Merchandising Association (NAMA), the organization that developed the international specification for the Multi-Drop Bus/ Internal Communication Protocol (MDB/CP) released in July 2010. The MDB/ICP enables communication between a master controller and any of the peripheral hardware like Coin Acceptors and bill validators. By adhering to these guidelines, any manufacturer’s equipment is interchangeable.

Turns out the Coin Acceptors I purchased don’t have the MDB interface necessary to communicate with a Vending Machine Controller (VMC). I reviewed the protocol and VMC/Peripheral Communication Specifications required by the Coin Acceptor/Changer peripheral and began work on developing an MDB interface that would bridge my Coin Acceptor with the multi-drop bus. 

Read the full article in the February 331 issue of Circuit Cellar

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Kit for R-Car V3M SoC Speeds Development

Renesas Electronics has announced the R-Car V3M Starter Kit to simplify and speed up the development of New Car Assessment Program (NCAP) front camera applications, surround view system, and LiDARs. The new starter kit is based on the R-Car V3M image recognition system-on-chip (SoC), delivering a combination of low power consumption and high performance for the growing NCAP front camera market. By combining the R-Car V3M starter kit with supporting software and tools, system developers can easily develop front camera applications, contributing to reduced development efforts and faster time-to-market.

Renesas also announced an enhancement to the R-Car V3M by integrating a new, highly power-efficient hardware accelerator for high-performance convolutional neural networks (CNNs), which enables features such as road detection or object classification that are increasingly used in automotive applications. The R-Car V3M’s innovative hardware accelerator enables CNNs to execute at ultra-low power consumption levels that cannot be reached when CNNs are running on CPUs or GPUs.

The new R-Car V3M Starter Kit, the R-Car V3M SoC, and supporting software and tools including Renesas’ open-source e² studio IDE integrated development environment (IDE), are part of Renesas’ open, innovative, and trusted Renesas autonomy Platform for ADAS and automated driving that delivers total end-to-end solutions scaling from cloud to sensing and vehicle control.

The new starter kit is a ready-to-use kit. In addition to the required interface and tools, the kit provides essential components for ADAS and automated driving development, including 2GB RAM, 4GB eMMC (embedded multi-media controller) onboard memory, Ethernet, display outputs, and interfaces for debugging. The integrated 440-pin expansion port gives full freedom for system manufacturers to develop application-specific expansion boards for a wide range of computing applications, from a simple advanced computer vision development environment to prototyping of multi-camera systems for applications such as surround view. This board flexibility reduces the time needed for hardware development in addition to maintaining a high degree of software portability and reusability.

The R-Car V3M Starter Kit is supported by a Linux Board Support Package (BSP), which is available through elinux.org. Further commercial operating systems will be made available from next year onwards. Codeplay will enable OpenCL and SYCL on the starter kit in Q1 2018. Further tools, sample code and application notes for computer vision and image processing will be provided throughout 2018. Renesas enables several tools on the R-Car V3M Starter Kit including Renesas e² studio toolchain and tools for debugging, which ease the development burden and enable faster time-to-market.

In addition to the R-Car V3M Starter Kit, Renesas has enabled ultra-low power consumption for CNNs, which achieve image recognition and image classification, on the R-Car V3M SoC. The R-Car V3M allows the implementation of high-performance, low power consumption CNN networks in NCAP cameras that cannot be realized with traditional high power consuming CPU or GPU architectures. Renesas complements the IMP-X5, a subsystem for computer vision processing that is composed of an image processor and the programmable CV engine, with a new, innovative CNN hardware accelerator developed in house, that allows the implementation of high-performance CNNs at ultra-low low power. With this new IP, Renesas enables system developers to choose between the IMP-X5 or the new hardware accelerator to deploy CNNs. This heterogeneous approach allows system developers to choose the most efficient architecture, depending on required programming flexibility, performance and power consumption.

The Renesas R-Car V3M is available now. The R-Car V3M Starter Kit with a Linux BSP will be available in Q1 2018 initially in limited quantities. A complete offering with an extended software solution is scheduled for Q3 2018.

Renesas Electronics | www.renesas.com

Bonus Newsletter: Displays and Graphics

Coming to your inbox tomorrow: January has a 5th Tuesday, so we’ve added a bonus topic to our four-week newsletter rotation. We’re bringing you a Bonus newsletter: Displays and Graphics. Display technology is where the user interacts with today’s modern embedded electronic devices This newsletter content examines the latest technology and product developments in displays along with the graphics ICs that drive those displays.

Plus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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You’ll get your Displays and Graphics newsletter issue tomorrow.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Analog & Power. (2/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch. (2/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (2/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(2/27 Wednesday) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Quantum Leaps

Input Voltage

–Jeff Child, Editor-in-Chief

JeffHeadShot

Throughout my career, I’ve always been impressed by Intel’s involvement in a wide spectrum of computing and electronics technologies. These range from the mundane and practical on one hand, to forward-looking and disruptive advances on the other. A lot of these weren’t technologies for which Intel ever intended to take direct advantage of over the long term. I think a lot about how Intel facilitated the creation of and early advances in USB. Intel even sold USB chips in the first couple years of USB’s emergence, but stepped aside from that with the knowledge that their main focus was selling processors.

USB made computers and a myriad of consumer electronic devices better and easier to use, and that, Intel knew, advanced the whole industry in which their microprocessors thrived. Today, look around your home, your office and even your car and count the number of USB connectors there are. It’s pretty obvious that USB’s impact has been truly universal.

Aside from mainstream, practical solutions like USB, Intel also continues to participate in the most forward-looking compute technologies. Exemplifying that, in January at the Consumer Electronics Show (CES) show in Las Vegas, Intel announced two major milestones in its efforts to develop future computing technologies. In his keynote address, Intel CEO Brian Krzanich announced the successful design, fabrication and delivery of a 49-qubit superconducting quantum test chip. The keynote also focused on the promise of neuromorphic computing.

In his speech, Krzanich explained that, just two months after delivery of a 17-qubit superconducting test chip, Intel that day unveiled “Tangle Lake,” a 49-qubit superconducting quantum test chip. The chip is named after a chain of lakes in Alaska, a nod to the extreme cold temperatures and the entangled state that quantum bits (or “qubits”) require to function.

According to Intel, achieving a 49-qubit test chip is an important milestone because it will allow researchers to assess and improve error correction techniques and simulate computational problems.

Krzanich predicts that quantum computing will solve problems that today might take our best supercomputers months or years to resolve, such as drug development, financial modeling and climate forecasting. While quantum computing has the potential to solve problems conventional computers can’t handle, the field is still nascent.

Mike Mayberry, VP and managing director of Intel Labs weighed in on the progress of the efforts. “We expect it will be 5 to 7 years before the industry gets to tackling engineering-scale problems, and it will likely require 1 million or more qubits to achieve commercial relevance,” said Mayberry.

Krzanich said the need to scale to greater numbers of working qubits is why Intel, in addition to investing in superconducting qubits, is also researching another type called spin qubits in silicon. Spin qubits could have a scaling advantage because they are much smaller than superconducting qubits. Spin qubits resemble a single electron transistor, which is similar in many ways to conventional transistors and potentially able to be manufactured with comparable processes. In fact, Intel has already invented a spin qubit fabrication flow on its 300-mm process technology.

At CES, Krzanich also showcased Intel’s research into neuromorphic computing—a new computing paradigm inspired by how the brain works that could unlock exponential gains in performance and power efficiency for the future of artificial intelligence. Intel Labs has developed a neuromorphic research chip, code-named “Loihi,” which includes circuits that mimic the brain’s basic operation.

While the concepts seem futuristic and abstract, Intel is thinking of the technology in terms of real-world uses. Intel says Neuromorphic chips could ultimately be used anywhere real-world data needs to be processed in evolving real-time environments. For example, these chips could enable smarter security cameras and smart-city infrastructure designed for real-time communication with autonomous vehicles. In the first half of this year, Intel plans to share the Loihi test chip with leading university and research institutions while applying it to more complex data sets and problems.

For me to compare quantum and neuromorphic computing to USB is as about as apples and oranges as you can get. But, who knows? When the day comes when quantum or neuromorphic chips are in our everyday devices, maybe my comparison won’t seem far-fetched at all.

This appears in the February (331) issue of Circuit Cellar magazine

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Next Newsletter: Embedded Boards

Coming to your inbox tomorrow: Circuit Cellar’s Embedded Boards newsletter. Tomorrow’s newsletter content focuses on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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You’ll get your Embedded Boards newsletter issue tomorrow.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

January has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Displays and Graphics. (1/30) Display technology is where the user interacts with today’s modern embedded electronic devices This newsletter content examines the latest technology and product developments in displays along with the graphics ICs that drive those displays.

Analog & Power. (2/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch. (2/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

IoT Technology Focus. (2/20) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Rad-Hard MCU Family Meets Space Needs

A new microcontroller that combines specified radiation performance with low-cost development associated with Commercial Off-The-Shelf (COTS) devices is now available from Microchip Technology. Developing radiation-hardened systems for space applications has a history of long lead times and high costs to achieve the highest level of reliability for multi-year missions in a harsh environment. Today, space and other critical aerospace applications require faster development and reduced costs.

The ATmegaS64M1 is the second 8-bit megaAVR MCU from Microchip that uses a development approach called COTS-to-radiation-tolerant. This approach takes a proven automotive-qualified device, the ATmega64M1 in this case, and creates pinout compatible versions in both high-reliability plastic and space-grade ceramic packages. The devices are designed to meet radiation tolerances with the following targeted performances:

  • Fully immune from Single-Event Latchup (SEL) up to 62 MeV.cm²/mg
  • No Single-Event Functional Interrupts (SEFI) which secure memory integrity
  • Accumulated Total Ionizing Dose (TID) between 20 to 50 Krad(Si)
  • Single Event Upset (SEU) characterization for all functional blocks

The new device joins the ATmegaS128, a radiation-tolerant MCU that has already been designed into several critical space missions including a Mars exploration plus a megaconstellation of several hundred Low Earth Orbit (LEO) satellites.

The ATmega64M1 COTS device, along with its full development toolchain including development kits and code configurator, can be used to begin development of hardware, firmware and software. When the final system is ready for the prototype phase or production, the COTS device can be replaced with a pin-out compatible, radiation-tolerant version in a 32-lead ceramic package (QFP32) with the same functionality as the original device. This leads to significant cost savings while also reducing development time and risk.

The ATmegaS64M1 meets the high operating temperature range of -55°C to +125°C. It is the first COTS-to-radiation-tolerant MCU to combine a Controller Area Network (CAN) bus, Digital-to-Analog Converter (DAC) and motor control capabilities. These features make it ideal for a variety of subsystems like remote terminal controllers and data handling functions for satellites, constellations, launchers or critical avionic applications.

To ease the design process and accelerate time to market, Microchip offers the STK 600 complete development board for the ATmegaS64M1, giving designers a quick start to develop code with advanced features for prototyping and testing new designs. The device is supported by Atmel Studio Integrated Development Environment (IDE) for developing, debugging and software libraries.

Microchip Technology | www.microchip.com

Designing a Home Cleaning Robot (Part 2)

Part 2: Mechanical Design

Continuing with this four-part article series about building a home cleaning robot, Nishant and Jesudasan discuss the mechanical aspects of the design.

By Nishant Mittal and Jesudasan Moses
Cypress Semiconductor

In part one (Circuit Cellar 329, December 2017) of this home cleaning robot article series, I discussed the introduction to the concepts of cleaning robots and the crucial design elements that are part of a skeleton design. Apart from that I discussed various selection criteria of the components. In this part, with the help of my colleague Jesudasan Moses, I’ll explore the mechanical aspects of the design. This includes selecting materials, aligning all the components on base, designing the pulleys for optimal performance, selecting motors and so on. The mechanical design for such a system can be very challenging because it’s a moving system and that adds complexity to the process. While this part is focused on mechanical issues and making the base ready, all this paves the way for when we add the “brains” into the system in part three.

DESIGN ELEMENTS

Figure 1 shows the block diagram of the mechanical design for this project. The overall structure of this design requires a base that is strong, but not too heavy. Using a metal base isn’t a good option for this type of system because it would increase the overall weight. Such an increase might mean that a higher torque motor would be required. The next elements are the motors and wheels. We chose to include motors only in the back. Using a front motor would probably be an overdesign for such a system. If you examine professionally designed home cleaning robots—like those I covered in part one—all of them had only the back motors for movement.

Figure 1
Mechanical arrangement of the home cleaning robot

On the front side of the unit, only rollers are added. This gives the system a complete 360-degree freedom of movement. The most important parts of the system are the cleaner and the roller. These are placed toward the center of the system and are controlled using an arrangement of motors and pulleys. In the front of the system, side brushes are added that again are controlled using motors. Now let’s look at the selection of each of the design elements.

Selection of the base shape: The base shape selection is very important because it defines how efficiently your home cleaning robot can clean at corners. A circular base shape is the most recommended option. A circular base enables the robot to move around corners and thereby cover each and every part of the house. That said, for a hobby project like this one, a rectangular base means no advanced tools are needed to cut and shape the base. With that in mind, we chose to use an acrylic material in a square shape for the base.

Motor selection: For our design, we opted for two movement motors on the back of the unit and another motor at the back for the roller pulley. On the front, there are two more motors to move the side brushes. We’ll save the more technical discussion about motor selection in part three. Choice of motor size depends upon the total weight that the front and back need to handle. The total weight should be equalized, otherwise the system won’t remain stable when the robot is moving fast. The placement of the two movement motors should be aligned to their center of axis. That ensures that when the robot is moving straight, it won’t divert its direction. It’s also important to buy those two motors from the same vendor to make sure they share the same mechanical properties.

Wheel Selection: It’s very important to decide on the net height of the system early on. Wheel selection is the deciding factor for the net height. .

Read the full article in the January 330 issue of Circuit Cellar

Don’t miss out on upcoming issues of Circuit Cellar. Subscribe today!
Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Tuesday’s Newsletter: IoT Tech Focus

Coming to your inbox tomorrow: Circuit Cellar’s IoT Technology Focus newsletter. Tomorrow’s newsletter covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Bonus: We’ve added Drawings for Free Stuff to our weekly newsletters. Make sure you’ve subscribed to the newsletter so you can participate.

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You’ll get your IoT Technology Focus newsletter issue tomorrow.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

Embedded Boards.(1/23 Wednesday) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

January has a 5th Tuesday, so we’re bringing you a bonus newsletter:
Displays and Graphics. (1/30) Display technology is where the user interacts with today’s modern embedded electronic devices This newsletter content examines the latest technology and product developments in displays along with the graphics ICs that drive those displays.

Analog & Power. (2/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AD-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (2/13) This newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

Tuesday’s Newsletter: Microcontroller Watch

Coming to your inbox tomorrow: Circuit Cellar’s Microcontroller Watch newsletter. Tomorrow’s newsletter keeps you up-to-date on latest microcontroller news. In this section, we examine the microcontrollers along with their associated tools and support products.

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Our weekly Circuit Cellar Newsletter will switch its theme each week, so look for these in upcoming weeks:

IoT Technology Focus. (1/16) Covers what’s happening with Internet-of-Things (IoT) technology–-from devices to gateway networks to cloud architectures. This newsletter tackles news and trends about the products and technologies needed to build IoT implementations and devices.

Embedded Boards.(1/23) The focus here is on both standard and non-standard embedded computer boards that ease prototyping efforts and let you smoothly scale up to production volumes.

January has a 5th Tuesday, so we’re bringing you a bonus newsletter:

Displays and Graphics. (1/30) Display technology is where the user interacts with today’s modern embedded electronic devices This newsletter content examines the latest technology and product developments in displays along with the graphics ICs that drive those displays.

Partner Program to Focus on Security

Microchip Technology has also established a Security Design Partner Program for connecting developers with third-party partners that can enhance and expedite secure designs. Along with the program, the company has also released its ATECC608A CryptoAuthentication device, a secure element that allows developers to add hardware-based security to their designs.

Microchip 38318249941_bf38a56692_zAccording to Microchip, the foundation of secured communication is the ability to create, protect and authenticate a device’s unique and trusted identity. By keeping a device’s private keys isolated from the system in a secured area, coupled with its industry-leading cryptography practices, the ATECC608A provides a high level of security that can be used in nearly any type of design. The ATECC608A includes the Federal Information Processing Standard (FIPS)-compliant Random Number Generator (RNG) that generates unique keys that comply with the latest requirements from the National Institute of Standards and Technology (NIST), providing an easier path to a whole-system FIPS certification.

Other features include:

  • Boot validation capabilities for small systems: New commands facilitate the signature validation and digest computation of the host microcontroller firmware for systems with small MCUs, such as an ARM Cortex-M0+ based device, as well as for more robust embedded systems.
  • Trusted authentication for LoRa nodes: The AES-128 engine also makes security deployments for LoRa infrastructures possible by enabling authentication of trusted nodes within a network.
  •  Fast cryptography processing: The hardware-based integrated Elliptical Curve Cryptography (ECC) algorithms create smaller keys and establish a certificate-based root of trust more quickly and securely than other implementation approaches that rely on legacy methods.
  •  Tamper-resistant protections: Anti-tampering techniques protect keys from physical attacks and attempted intrusions after deployment. These techniques allow the system to preserve a secured and trusted identity.
  •  Trusted in-manufacturing provisioning: Companies can use Microchip’s secured manufacturing facilities to safely provision their keys and certificates, eliminating the risk of exposure during manufacturing.

In addition to providing hardware security solutions, customers have access to Microchip’s Security Design Partner Program. These industry-leading companies, including Amazon Web Services (AWS) and Google Cloud Platform, provide complementary cloud-driven security models and infrastructure. Other partners are well-versed in implementing Microchip’s security devices and libraries. Whether designers are looking to secure an Internet of Things (IoT) application or add authentication capabilities for consumables, such as cartridges or accessories, the expertise of the Security Design Partners can reduce both development cost and time to market.

For rapid prototyping of secure solutions, designers can use the new CryptoAuth Xplained Pro evaluation and development kit (ATCryptoAuth-XPRO-B) which is an add-on board, compatible with any Microchip Xplained or Xplained Pro evaluation board. The ATECC608A is available for $0.56 each in 10,000 unit quantities. The ATCryptoAuth-XPRO-B add-on development board is available for $10.00 each.

Microchip Technology | www.microchip.com