Embedded Software: Tips & Insights (Sponsor: PRQA)

When it comes to embedded software, security matters. Read the following whitepapers to learn about: securing your embedded systems, MISRA coding standard, and using static analysis to overcome the challenges of reusing code.

  • Developing Secure Embedded Software
  • Guide to MISRA Coding
  • Using Static Analysis to Overcome the Challenges of Reusing Code for Embedded Software


Programming Research Ltd (PRQA) helps its customers to develop high-quality embedded source code—software which is impervious to attack and executes as intended.

The Future of Automation

The robot invasion isn’t coming. It’s already here. One would be hard-pressed to find anything in modern “industrialized” society that doesn’t rely on a substantial level of automation during its life cycle—whether in its production, consumption, use, or (most probably) all of the above. Regardless of the definition du jour, “robots” are indeed well on their way to taking over—and not in the terrifying, apocalyptic, “Skynet” kind of way, but in a way that will universally improve the human condition.

Of course, the success of this r/evolution relies on an almost incomprehensible level of compounding innovations and advancements accompanied by a mountain of associated technical complexities and challenges. The good news is many of these challenges have already been addressed—albeit in a piecemeal manner—by focused professionals in their respective fields. The real obstacle to progress, therefore, ultimately lies in the compilation and integration of a variety of technologies and techniques from heterogeneous industries, with the end goal being a collection of cohesive systems that can be easily and intuitively implemented in industry.

Two of the most promising and critical aspects of robotics and automation today are human-machine collaboration and flexible manufacturing. Interestingly (and, perhaps, fortuitously), their problem sets are virtually identical, as the functionality of both systems inherently revolves around constantly changing and wildly unpredictable environments and tasks. These machines, therefore, have to be heavily adaptable to and continuously “aware” of their surroundings in order to maintain not only a high level of performance, but also to consistently perform safely and reliably.

Not unlike humans, machines rely on their ability to collect, analyze, and act on external data, oftentimes in a deterministic fashion—in other words, certain things must happen in a pre-defined amount of time for the system to perform as intended. These data can range from the very slow and simple (e.g., calculating temperature by reading the voltage of a thermocouple once a second) to the extremely fast and complex (e.g., running control loops for eight brushless electric motors 25,000-plus times a second). Needless to say, giving a machine the ability to perceive—be it through sight, sound, and/or touch—and act on its surroundings in “real time” is no easy task.

Read more Tech the Future essays and get inspired!

Computer vision (sight and perception), speech recognition (sound and language), and precision motion control (touch and motor skills) are things most people take for granted, as they are collectively fundamental to survival. Machines, however, are not “born” with—nor have they evolved—these abilities. Piling on additional layers of complexity like communication and the ability to acquire knowledge/learn new tasks, and it becomes menacingly apparent how substantial the challenge of creating intelligent and connected automated systems really is.

While the laundry list of requirements might seem nearly impossible to address, fortunately the tools used for integrating these exceedingly complex systems have undergone their own period of hyper growth in the last several years. In much the same way developers, researchers, engineers, and entrepreneurs have picked off industry- and application-specific problems related to the aforementioned technical hurdles, as have the people behind the hardware and software that make it possible for these independently developed, otherwise standalone solutions to be combined and interwoven, thus resulting in truly world-changing innovations.

For developers, only in the last few years has it become practical to leverage the combination of embedded technologies like the power-efficient, developer-friendly mobile application processor with the flexibility and raw “horsepower” of programmable logic (i.e., field-programmable gate arrays, which have historically been reserved for the aerospace/defense and telecommunication industries) at scales never previously imagined. And with rapidly growing developer communities, the platforms built around these technologies are directly facilitating the advancement of automation, and doing it all under a single silicon “roof.” There’s little doubt that increasing access to these new tools will usher in a more nimble, intelligent, safe, and affordable wave of robotics.

Looking forward, automation will undoubtedly continue to play an ever-increasingly central role in day-to-day life. As a result, careful consideration must be given to facilitating human-machine (and machine-machine) collaboration in order to accelerate innovation and overcome the technical and societal impacts bred from the disruption of the status quo. The pieces are already there, now it’s time to assemble them.

This article appears in Circuit Cellar 320.

Ryan Cousins is cofounder and CEO of krtkl, Inc.http://krtkl.com/ (“critical”), a San Francisco-based embedded systems company. The krtkl team created snickerdoodle—an affordable and highly reconfigurable platform for developing mechatronic, audio/video, computer vision, networking, and wireless communication systems. Ryan has a BS in mechanical engineering from UCLA.  He has experience in R&D, project management, and business development in the medical and embedded systems industries. Learn more at krtkl.com or snickerdoodle.io.

Programming-Free LCD User Interface for Embedded Applications

LCDTERM.com recently launched a new programming-free LCD user interface, which allows for seamless and code-free integration onto any embedded platform. Eliminating the need to write software to control the display, the LCDTERM user interface does not require LCD programming knowledge, so you can focus more on desired functionality rather than writing device drivers. Its three-button keyboard allows developers to implement a full user interface without having to worry about reading buttons, debouncing, or programming resources on the host embedded system.LCD term

The LCDTERM interface includes all control firmware and uses a speedy ARM M0 processor. It comes with a free API. Included font and user-defined bitmaps allows for addition of 64K color displays to any embedded system. Display sizes begin at 1.77″ and are ready to ship immediately in high quantities. Larger sizes of 2.8″ and 5″ are also available. LCDTERM.com can scale for custom sizes, and it is equipped to enter into OEM arrangements. Free demo kits are available for applications via the website.

Source: LCDTERM.com

STMicroelectronics To Manufacture USound’s Patented Thin-Film Piezo-Electric MEMS Micro-Speaker Technology

STMicroelectronics and Austrian company USound GmbH announced their collaboration on the industrialization and production of the world’s first miniature piezoelectric MEMS actuators for smart audio systems in portable devices. The patented micro-speaker technology from USound aims to replace commonly used balanced-armature and electrodynamic receivers for handsets with a small piezo-MEMS actuator.STMicro USoundSpeakerMEMS

Manufactured using STMicroelectronics’s industry-leading thin-film piezoelectric (TFP) technology, these actuators will improve scalability and cost while assuring lower power consumption and heat dissipation in hearables and smartphones devices, without compromising audio quality.

USound and STMicroelectronics anticipate the piezoelectric MEMS actuator will move into production in Q3 of this year and will be shipping in consumer products by the end of the year.

Source: STMicroelectronics

New Precision Rail-to-Rail Op-Amps

Linear Technology’s new LTC6258/59/60 and LTC6261/62/63 are part of a family of power-efficient op-amps ranging from 1.3 MHz GBW product at 20 µA supply current to 720 MHz GBW product at 3.3 mA supply current. The op-amps operate on 1.8-to-5.25-V supply, feature rail-to-rail inputs and outputs, and include versions with a Shutdown mode. Input offset voltage is 400 μV maximum. The devices are fully specified over the industrial (I, –40°C to 85°C) and extended (H, –40°C to 125°C) temperature ranges.Linear LTC6258

With supply current of only 20 μA per amplifier, the LTC6258/59/60 achieve 1.3 MHz gain bandwidth product and 240 V/ms slew rate. They include input EMI filters which provide 45 dB rejection at 1 GHz. They are stable for any gain and with any capacitive load.

The LTC6261/62/63 achieve 30 MHz GBW product and 7 V/μs slew rate, drawing just 240 μA per amplifier. Wideband voltage noise is just 13 nV/√Hz. They are stable for any gain and for capacitive loads up to 1 nF.

The single LTC6258 and LTC6261 are available in a space saving 2 mm × 2 mm DFN package, priced starting at $1.24 each in quantities of 1000 pieces. The dual LTC6259 and LTC6262 are available in the same size DFN package, as well as eight-lead SOT-23, MSOP-8, and MSOP-10 with Shutdown mode. The quad LTC6260 and LTC6263 are available in the MSOP-16 package.

LTC6258/59/60/61/62/63’s specs, features, and benefits:

  • Offset voltage: 400 μV maximum
  • Rail-to-rail input and output
  • Supply voltage range: 1.8 to 5.25 V
  • Operating temperature range: –40°C to 125°C
  • Single in 2 mm × 2 mm DFN packages
  • Dual in eight-lead MS8, MS10, TS0T-23, 2 mm × 2 mm DFN Packages
  • Quad in MS16 package

LTC6258/59/60’s specs, features, and benefits:

  • Gain bandwidth product: 1.3 MHz
  • Low quiescent current: 20 μA
  • C-load op-amp drives all capacitive loads
  • EMI rejection ratio: 45 dB at 1 GHz
  • Input bias current: 75 nA maximum
  • CMRR/PSRR: 95 dB/90 dB
  • Shutdown current: 7 μA maximum

LTC6261/62/63 specs, features, and benefits:

  • Gain bandwidth product: 30 MHz
  • Low quiescent current: 240 μA
  • Drives capacitive loads up to 1 nF
  • Input bias current: 100 nA maximum
  • CMRR/PSRR: 100 dB/95 dB
  • Shutdown current: 9 μA maximum

Source: Linear Technology

Interview: Massimo Banzi, Codeveloper of Arduino

It’s no secret that the Arduino development board has changed the way we look at working with electronics. All over the world, the little board has enabled millions of engineers, students, artists, and makers to get electronics projects up and going. We recently traveled to DotDotDot in Milan, Italy, to chat with Arduino codeveloper Massimo Banzi, who talked about the history of Arduino, the importance of makerspaces, and more.

Watch the video

BitCloud 4.0 Complete ZigBee Software Development Kit

Microchip Technology recently announced the industry’s first ZigBee alliance-certified ZigBee platform with ZigBee PRO and Green Power features (formerly ZigBee 3.0). The software stack and corresponding BitCloud 4.0 software development kit is well-suited for the design of home automation and Internet of Things (IoT) applications. Enableing cross-functional device support, the solution is backward-compatible with existing ZigBee-certified products for seamless interoperability.Zigbee Microchip

Features, specs, and benefits:

  • Low latency suitable for RF remote applications
  • Mesh networking for large networks such as lighting applications
  • The ZigBee PRO Green Power feature enables battery-less devices to securely join a network
  • ZigBee Light Link and ZigBee Home Automation devices are fully supported.

The BitCloud 4.0 Software Development Kit (SDK) enables application development on the SAM R21 Xplained Pro Evaluation Kit, a Cortex M0+-based 32-bit microcontroller with an integrated 2.4-GHz 802.15.4-compliant radio. When used with the newly certified software stack, the SDK provides a complete ZigBee-certified development platform.

Microchip currently offers two platforms to begin ZigBee development. The SAM R21 Xplained Pro Evaluation Kit (ATSAMR21-XPRO) is available for $58. The SAM R21 ZigBee Light Link Evaluation Kit (ATSAMR21ZLL-EK) costs $92.

Source: Microchip Technology

Mouser Stocks STM32 LoRaWAN Discovery Board

Mouser Electronics currently offers the STMicroelectronics STM32 LoRaWAN Discovery Board. The new Discovery Kit and I-NUCLEO-LRWAN1 STM32 LoRa Arduino-compatible extension board (available to order from Mouser) offer you a development platform for learning and evaluating solutions based on LoRa and FSK/OOK radio frequency (RF) communication.Mouser_STSTM32LoRaWAN

The ST STM32 LoRaWAN Discovery Kit is based on an all-in-one Murata Type ABZ open module solution to address low-power wide area networks (LPWAN) and support the LoRaWAN long-range wireless protocol. An STM32L072 ARM Cortex-M0+ microcontroller—featuring 192 KB of flash memory, 20 KB of RAM, and 6 KB of EEPROM—powers the Type ABZ mdoule. The STM32L0 ultra-low-power microcontroller offers low-power design features, targeting battery-powered and energy-harvesting applications.

ST’s I-NUCLEO-LRWAN1 STM32 LoRa extension board includes a LoRaWAN module powered by an STM32L052 microcontroller, an SMA connector, a 50-Ω antenna, and headers compatible with Arduino Uno R3 boards. The board features three ST environmental sensors: an LSM303AGR accelerometer and magnetometer, an HTS221 relative humidity and temperature sensor, and an LPS22HB pressure sensor.

Both the Discovery board and NUCLEO board come with LoRaWAN class A-certified I-CUBE-LRWAN embedded software that enables designers to set up a complete LoRaWAN node.

Source: Mouser Electronics

New Audio DAC Offers High-Res Audio to Pro Audio Devices

Cirrus Logic recently introduced the CS43130 MasterHIFI, which is a low-power, digital-to-analog converter (DAC) featuring a headphone amplifier. Operating at 4× lower power consumption, the CS43130 DAC supports Direct Stream Digital (DSD) formats and includes a NOS Filter and 512 single-bit elements to eliminate unwanted noise from the signal and for best filter response. The IC minimizes board space requirements while enabling performance and features to drive design differentiation.Cirrus CS43130

The CS43130’s features, specs, and benefits:

  • Supports DSD, DSD DoP (DSD over PCM), up to DSD128 and all PCM high-resolution audio formats up to 32-bit 384 kHz
  • Proprietary DSD processor handles switching between DSD and PCM audio streams, while matching the analog audio output level
  • Advanced hi-fi filters, allowing OEMs to tune their own signature sound
  • Analog bypass switch provides easy switching between hi-fi and voice call modes and includes a low-power state for voice only
  • Unique Non-Oversampling (NOS) emulation mode
  • High impedance of 600 Ω and inter-channel isolation of greater than 110 dB.
  • Proprietary digital-interpolation filters support five selectable digital filter responses.
  • On-board, low-noise, ground-centered headphone amplifier provides proprietary AC impedance detection to support headphone fingerprinting
  • Uses 512 individual DACs per channel in an analog/digital filter array
  •  THD+N of –108 dB and dynamic range of 130 dB
  •  Consumes 23 mW of power
  • Supports up to 32-bit, 384-kHz sample rate audio playback

The CS43130 and CS4399 are available in a 42-ball WLCS or a 40-pin QFN package. A development kit is also available.

Source: Cirrus Logic

Electrical Engineering Crossword (Issue 320)

The answers to Circuit Cellar 320‘s crossword are now available.320-empty-grid-(key)


  1. BRIDGE—Connects two LANs or two sections of the same LAN
  2. ZETTABYTE—1,180,591,620,717,411,303,424 bytes
  3. HELIX—Spring-shaped curve
  5. HAMMING—Code that detects single- and double-bit errors
  6. DEGAUSS—Decrease magnetism
  7. NULL—Character with bits set to zero
  8. MECHATRONICS—Mechanics + electronics + computing
  9. INFINITE—Unending series
  10. PICOSECOND—One trillionth of a second


  1. QUARTZ—Timing crystal
  2. RHEOSTAT—A variable resistor
  3. DUTY—Time of one on/off cycle
  4. CASCADING—Circuits feeding one another
  5. PHOTONICS—Science of light
  6. FIRMWARE—Program in read-only memory
  7. ENIAC—30-ton computer; UPENN; 1946
  9. FERRIC—Magnetic tape coating that uses iron oxide
  10. SONAR—A method for detecting objects, especially those under water, with sound waves
  11. BITMAP—2-D pixel array

Issue 320: EQ Answers

Problem 1: A certain CPU has three blocks of combinatorial logic that are used in each instrucion cycle, and these have delays of 7 ns, 3 ns, and 10 ns, respectively. A register in this technology has a total of 2 ns of setup time and propagation delay. What is the throughput of this CPU if no pipelining is used?

Answer 1: The minimum clock period in a non-pipelined implementation is defined by the propagation delay of the logic, plus the overhead (setup time plus propagation delay) of one register. For this example, these times add up to 7 + 3 + 10 + 2 = 22 ns, which corresponds to a clock frequency of 45.45 MHz. One instruction is completed per clock cycle, so the throughput is 45.45 MIPS.

Problem 2: Instruction latency is the time required for one instruction to complete. What is the latency for this CPU?

Answer 2: The instruction latency for the non-piplined CPU is the same as the clock period, 22 ns.

Problem 3: Pipelining is the process of inserting additional registers into a sequence of combinatorial blocks so that different blocks can be processing different instructions at the same time. What is the maximum clock frequency if we introduce pipelining to this CPU, and how many pipeline registers are required?

Answer 3: The longest single stage of combinatorial logic requires 10 ns, so this puts the lower limit on the clock period of 10 ns + 2 ns (register overhead) = 12 ns, which is a clock frequency of 83.33 MHz. Since the total of the other two combinatorial blocks also happens to add up to 10 ns, only one pipeline register is required.

Problem 4: What is the throughput and instruction latency for the pipelined CPU?

Answer 4: An instruction is still completed on every clock cycle, so now the throughput is 83.33 MIPS, for a speedup of 1.833×. However, each instruction now requires two clock cycles to complete, so the instruction latency is 2 × 12 ns = 24 ns, slightly (9.1%) longer than the non-pipelined CPU.

Contributor: David Tweed

The Importance of Widely Available Wireless Links for UAV Systems

Readily available, first-rate wireless links are essential for building and running safe UAV systems. David Weight, principal electronics engineer at Waittcircuit, recently shared his thoughts on the importance developing and maintaining high-quality wireless links as the UAV industry expands.

weightOne of the major challenges that is emerging in the UAV industry is maintaining wireless links with high availability. As UAVs start to share airspace with other vehicles, we need to demonstrate that a control link can be maintained in a wide variety of environments, including interference and non-line of sight. We are starting to see software defined radio used to build radios which are frequency agile and capable of using multiple modulation techniques. For example, being able to use direct links in open spaces where these are most effective, but being able to change to 4G type signals when entering more built-up areas as these areas can pose issues for direct links, but have good coverage for existing commercial telecoms. Being able to change the frequency and modulation also means that, where interference or poor signal paths are found, frequencies can be changed to avoid interference, or in extreme cases, be reduced to lower bands which allow control links to be maintained. This may mean that not all the data can be transmitted back, but it will keep the link alive and continue to transmit sufficient information to allow the pilot to control the UAV safely. — David Weight (Principal Electronics Engineer, Wattcircuit, UK)

New Range of RF Building Blocks

CML Microcircuits recently released a new range of RF power amplifiers. The CMX901 is a three-stage wideband, high-gain, high-efficiency RF power amplifier IC operating over 130 to 950 MHz. The device is ideally suited for use in VHF/UHF radio applications such as data modules, marine VHF communications, and RFID readers/writers used in Industrial Internet of Things (IIOT) systems. High power added efficiency supports battery-powered applications.CML CMX901

The amplifier’s first and second stages operate in a class-A and class-AB mode, respectively. The third stage operates in class-C mode for maximum efficiency. Input and output matched circuits are implemented via external components. They can be adjusted to obtain maximum power and efficiency at the desired operating frequency.

The CMX901 is available in a small footprint 5 mm × 5 mm low thermal resistance 28-pin WQFN package, which makes it ideal for small form factor applications.

Source: CML Microcircuits

New Cyclone 10 FPGA Family

Intel recently launched the Intel Cyclone 10 family of FPGAs. Well suited for IoT applications, the new FPGAs are designed to deliver fast and power-efficient processing. They can collect and send data, and make real-time decisions based on the input from IoT devices. You can program the FPGAs  to deliver the specific level of computing and functions required by different IoT applications.Cyclone INTEL

Cyclone 10 GX supports 10G transceivers and hard floating point digital signal processing (DSP). Furthermore, it offers 2× the performance of the previous Cyclone generation. The architectural innovation in the implementation of IEEE 754 single-precision hardened floating-point DSP blocks can enable processing rates up to 134 giga floating-point operations per second (GFLOPs) for applications such as motion or motor control systems.

The Intel Cyclone 10 LP is the perfect solution for applications where cost and power are key factors in the design decision. These systems typically use FPGA densities that are sub 75K LE and chip-to-chip bridging functions between electronic components or I/O expansion for micro-processors. Cyclone 10 LP can also be used for automotive video processing used in rear-view cameras and in sensor fusion, where data gathered while the car is on the road is combined from multiple sensors in the car to provide a more complete view of what is happening.

The Cyclone 10 FPGA family will be available in the second half of 2017, along with evaluation kits, boards, and the latest version of Intel’s Quartus FPGA programming software.

Source: Intel

New Electrical Installation Calculation Software

Trace Software International recently released elec calc 2017, which is a software solution that enables the real-time sizing of electrical installations. elec calc complies with various international standards.elec-calc Trace

Features, specs, and benefits:

  • Calculations: power balance calculation; cable cross-section calculation; operating modes; load balancing; electrical selectivity; and electrical back-up
  • Contextual menus, a ribbon interface, and an UNDO/REDO button available for all features
  • Intellisense feature facilitates and accelerates production of the one-line diagram by suggesting components to be connected to the selected one
  • A personal library containing saved plans and components
  • Several types of sources simulating different scenarios
  • Short-circuit currents calculated according to IEC 60909 using the method of symmetrical components or according to the method of installation IEC 60354
  • Electrical calculation report
  • Single-line diagram
  • Excel import/export module
  • Export module to elecworks or Solidworks Electrical
  • Equipment/component/manufacturer database

Source: Trace Software International