Build an RGB LED Controller

Using Parallel FET Dimming

There are a lot of fun and interesting things you can do with LEDs and the different ways to control them. In this article, Dirceu describes an alternative approach to control RGB LEDs, using the parallel FET dimming technique. He steps through his efforts to design and build an alternative lighting system based on power RGB LEDs. To control them he goes very old school and uses an 8-bit MCU and the BASIC programming language.

By Dirceu R. Rodrigues, Jr.

Nowadays, applications involving advanced processors like Arm and Espressif ESP-32 are commonplace. But I thought it would be cool to test some fun lighting sequences that are controlled by an 8-bit microcontroller (MCU) programmed using an ancient language: BASIC. Although using pulse-width modulation (PWM) to dim LEDs with MCUs is a long-established idea and there’s a plethora of such products on the market, my approach differs from others regarding the drive method used. The benefit will be a relatively shorter BOM, but is also of particular interest to embedded system designers involved with LEDs because it will be possible to experiment with alternative configurations for the control stage.

LEDs are inherently nonlinear devices. Their brightness depends primarily on the current flowing through them, even though the voltage on terminals don’t vary that much. To achieve a constant LED current, there are two approaches: linear or switched current regulation. A linear regulator is preferred in situations where the noise due to commutation would be unacceptable—or for example, in high-precision measurement equipment. When efficiency is the main concern, a switched regulator or driver usually is chosen.

A commercially available driver usually operates above 1 MHz, providing hysteretic regulation for the LED current. To implement the required dimming, a common solution is to apply a PWM signal to an enable pin of the regulator. Because the entire component is switched continuously, the delay due to the soft start function must be taken into account. The disadvantage of this mode is, therefore, the limitation at low frequencies, usually 100 Hz. Other drivers, such as the ZXLD1350 from Diodes Inc. (used here), have a similar input named ADJ, capable of accepting a PWM signal up to 1 kHz.

Figure 1
Shown here is the basic idea for the design.

As outlined in Figure 1, my application takes a different approach. Rather than applying PWM pulses to a dedicated regulator pin, these signals are used to “short-circuit” the LED. So, when a switch is closed, the corresponding LED is off. This technique—known as parallel FET dimming—does not pose a problem itself, since the driver is based on a current source. Regardless of the state of each LED, the same current always flows through the entire circuit. For an independent control of three RGB LEDs, traditionally three drivers are employed, each with its own inductor, Schottky diode and sensor resistor, as shown in Figure 2a.

Figure 2
(left) shows a traditional configuration for driving 3 LEDs. (right) shows my alternative configuration, which reduces the number of components by connecting the three LEDs in series.

My alternative configuration to reduce the number of components is to connect the three LEDs in series, each with its own switch driven by PWM (Figure 2b). Note that, in this case, the ADJ pin from the single ZXLD1350 stays floating, and the three PWM signals are moved to the gate of MOSFETs. Therefore, it is possible to control three LEDs using only one set, consisting of driver, sense resistor, flyback diode and inductor. …

Read the full article in the August 349 issue of Circuit Cellar
(Full article word count: 2287 words; Figure count: 9 Figures.)

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IoT Modules Enable Large-Scale LTE-M and NB-IoT Deployments

Telit has announced the ME310G1 (shown) and ME910G1 modules, designed for mass-scale LTE-M and NB-IoT deployments that feature hundreds of thousands or millions of devices. Based on the new Qualcomm 9205 LTE modem and featuring optional 2G fallback, the modules also provide a future-proof foundation for IoT deployments that span legacy networks, 4G and 5G.
The ME310G1 and ME910G1 are the first 3GPP Release 14 additions to the Telit portfolio and the first members of Telit’s new series based on the Qualcomm 9205 LTE IoT Modem, which was announced in late 2018. The highly compact chipset enables Telit to meet booming global demand for ultra-small modules for applications such as wearable medical devices, fitness trackers and industrial sensors.

The new modules are ideal for battery-powered applications via improved features such as Power Saving Mode (PSM) and extended Discontinuous Reception (eDRX), which periodically wakes up the device to transmit only the smallest amounts of data necessary before returning to sleep mode. Both modules also ensure reliable indoor connections, with a maximum coupling loss of up to +15dB/+20dB for superior in-building penetration compared to earlier LTE standards.

The multi-band ME310G1 and ME910G1 are available in versions with 2G fallback for use in areas where LTE-M/NB-IoT service is yet to be deployed. These versions also support GSM voice and will support VoLTE for applications that require the ability to make phone calls.

The ME910G1 is the latest member of Telit’s best-selling xE910 and family. The ME910G1 is also a drop-in replacement in existing devices based on the family’s modules for 2G, 3G and the various categories of LTE. With Telit’s design-once-use-anywhere philosophy, developers can cut costs and development time by simply designing for the xE910 LGA common form factor, giving them the freedom to deploy technologies best suited for the application’s environment.

The ME310G1 LTE-only variant is less than 200 mm-squared and variant with 2G fallback is less than 300 mm2-squared and they enable enterprises to deploy new small footprint designs across many application areas including asset tracking, health-care monitoring, smart metering, portable devices, industrial sensors, home automation, and others that benefit from low-power and low-data rate capabilities. The xE310 family’s flexible perimeter footprint includes pin-to-pin compatible 2G and 4G modules, enabling integrators to design a single PCB layout and deploy a combination of technologies.

ME310G1 and ME910G1 samples are now available. Mass production begins in late 2019 and Q1 2020, depending on the product version.

Telit | www.telit.com

Controllers Ease EMI Qualification of Automotive Touchscreens

Three new maXTouch touchscreen controllers and optimization services are now available from Microchip Technology to address electromagnetic interference (EMI) and electromagnetic compatibility (EMC) challenges faced by developers of automotive touchscreens. The TD family of touch controllers features a new differential mutual signal acquisition method that significantly increases the Signal-to-Noise Ratio (SNR). This allows the use of very thick glass or plastic cover lenses and multi-finger thick gloved touch support up to the equivalence of 4.5 mm polymethyl methacrylate (PMMA).

The MXT1067TD, MXT1189TD and MXT1665TD devices add several variants that are cost optimized for nine- to 13-inch automotive touchscreens to Microchip’s portfolio and are complemented by the recently-introduced MXT449TD, MXT641TD, MXT2113TD and MXT2912TD devices supporting up to 20-inch touchscreens. Each device addresses aspects of the increasing demand for functional safety features and is designed in accordance with the Automotive SPICE Level 3 capability and ISO 26262 Automotive Safety Integrity Level (ASIL) B requirements.

All devices in the TD family feature a unique waveform shaping capability to optimize the performance of the touch controller’s radiated emissions through an EMI optimization tool. Working with product experts in Microchip’s worldwide application design centers, this tool allows developers to enter user-defined RF limits and tune the shape of the transmitted burst waveform used for the touch sensing acquisition.

Waveform shaping is achieved through firmware parameters derived from the tool and helps designers to position the fundamental burst frequency to work together with other in-vehicle applications, such as the remote keyless entry system. The resulting parameters are then simply added to the maXTouch configuration file, which customizes the touch controller performance to the individual customer design. This process can save the designer many hours, or even weeks, of expensive EMC test chamber time by eliminating experimentation with different configuration settings to achieve the desired EMI/EMC performance, says Microchip.

Development Tools

An evaluation kit is available for each of the parts in the new maXTouch touchscreen controller family. Kit numbers are ATEVK-MXT1067TDAT-A (I2C), ATEVK-MXT1189TDAT-A (I2C), ATEVK-MXT1189TDAT-C (SPI), ATEVK-MXT1665TDAT-A (I2C) and ATEVK-MXT1665TDAT-C (SPI). Each kit includes a Printed Circuit Board (PCB) with the maXTouch touchscreen controller, a touch sensor on a clear glass lens, the Flat Printed Circuit (FPC) to connect to the sensor, a bridge PCB to connect the kit to the host computer via USB, as well as cables, software and documentation. All parts are also compatible with maXTouch Studio, a full software development environment to support the evaluation of maXTouch touchscreen controllers.

The maXTouch EMI optimization service will be made available as part of the system support provided by one of Microchip’s worldwide application design centers.

The MXT1067TD, MXT1189TD and MXT1665TD devices are available now in sampling and volume quantities in TQFP128 (MXT1067TD only) and LQFP144 packages.

Microchip Technology | www.microchip.com

Bonus Newsletter: PCB Design Tools

We have a BONUS newsletter for you this week: PCB Design Tools! The process of PCB design is always facing new complexities. Rules-based autorouting, chips with higher lead counts and higher speed interconnections are just a few of the challenges forcing PCB design software to keep pace. This newsletter updates you on the latest happenings in this area.

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

Already a Circuit Cellar Newsletter subscriber? Great!
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:

Analog & Power. (8/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (8/13) 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. (8/20) 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.(8/27) 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

Tiny Amplifiers Enable Small High Performance System Designs

Texas Instruments has introduced what it claims is the industry’s smallest current-sense amplifier in a leaded package and the smallest, most accurate comparators with an internal 1.2-V or 0.2-V reference. Offered in industry-leading package options, the INA185 current-sense amplifier, and open-drain TLV4021 and push-pull TLV4041 comparators enable engineers to design smaller, simpler and more integrated systems while maintaining high performance. In addition, pairing the amplifier with one of the comparators produces the smallest, highest performing overcurrent detection solution in the industry, says TI.

These new devices are optimized for a variety of personal electronics, enterprise, industrial and communications applications, including peripherals, docking stations and notebooks. With a small-outline transistor (SOT)-563 package measuring 1.6 mm by 1.6 mm (2.5 mm2), the amplifier is 40% smaller than the closest competitive leaded packages. Featuring a 55-µV input offset that enables higher precision measurements at low currents, the INA185 enables the use of lower-value shunt resistors to cut system power consumption. Additionally, its 350-kHz bandwidth and 2-V/µS slew rate enable phase-current reproduction to enhance motor efficiency and save system power.

The precisely matched resistive gain network in the amplifier enables a maximum gain error as low as 0.2%, which contributes to robust performance over temperature and process variations. The device’s typical response time of 2 µs enables fast fault detection to prevent system damage.

System designers can add functionality in the same form factor and enable high-performance design with the TLV4021 and TLV4041 comparators. Available in an ultra-small die-size ball-grid array (DSBGA) 0.73-mm-by-0.73-mm package, the comparators’ integrated voltage reference saves board space while supporting precise voltage monitoring, which optimizes system performance.

The comparators can monitor voltages as low as the 0.2-V internal reference, and feature a high threshold accuracy of 1% across a full temperature range from -40°C to +125°C. Low 2.5-µA quiescent current delivers extended battery life for smart, connected devices. Fast propagation delay as low as 450 ns reduces latency, enabling power-conscious systems to monitor signals and respond quickly to fault conditions.

When using both the INA185 and the TLV4021 or TLV4041, engineers can shrink their total footprint to enable smaller systems. In combination, these devices produce the smallest, highest-performing overcurrent detection solution–15% smaller and 50 times faster than competitive devices. Pairing the amplifier with one of the comparators to support overcurrent detection on rails as high as 26 V delivers more headroom to better manage current spikes.

Production quantities of the INA185 are now available through the TI store and authorized distributors in a SOT-563 package, measuring 1.6 mm by 1.6 mm. Pricing starts at US$0.65 in 1,000-unit quantities. Production quantities of the push-pull TLV4041 and preproduction samples of the open-drain TLV4021 comparators are now available through the TI store and authorized distributors in an ultra-small DSBGA package, measuring 0.73 mm by 0.73 mm. Pricing for each comparator starts at US$0.39 in 1,000-unit quantities.

Texas Instruments | www.ti.com

Tool Simplifies STM32 MCU Programming and Protects IP

STMicroelectronics has released the latest version of the STM32CubeProgrammer software tool for STM32 microcontroller (MCU) and microprocessor (MPU) users. STM32CubeProgrammer lets users program their devices through any convenient connection, choosing from the MCU’s JTAG or single-wire debug (SWD) pins, a UART, or USB, SPI, I2C or CAN interfaces.

The new multi-OS software replaces several tools including ST Visual Programmer (STVP), DFuSe USB Device Firmware Upgrade programmer, Windows-only STM32 Flash loader and software utilities for use with ST-Link. It is designed to deliver maximum flexibility with the benefits of a consistent unified environment. From now on, new STM32 products will be supported only by STM32CubeProgrammer.

Built-in features include the STM32 Trusted Package Creator, which protects OEMs’ intellectual property by encrypting firmware using an AES-GCM key and working with the STM32HSM-V1 companion Hardware Security Module (HSM). The HSM manages authentication and licensing, with counter-limited Secure Firmware Install (SFI) allowing OEMs to restrict the number of devices that can be programmed. The first STM32HSM with maximum programming count of 300 units for prototyping will be available at the end of July 2019.

STMicroelectronics | www.st.com

 

PICMG to Develop COM Open Spec for Server-Level Edge Computing

PICMG has announced that it has recently formed the COM-HPC technical subcommittee. It is actively developing a new COM (Computer-On-Module) specification to meet the increasing requirements of edge computing applications. Well suited for a wide range of applications, PICMG’s popular COM Express has been adopted worldwide and is anticipated to grow and thrive over the next decade.

According to multiple research reports, the computer-on-module (COM) market is expanding rapidly and is expected to reach over $1 billion by 2022. The technical requirements to bring server-level computing to the edge have driven the need to create new open specifications to complement COM Express. PICMG members have long been at the forefront of designing and supplying edge computing solutions and are collaborating to meet the requirements of applications well into the future.

PICMG says the new COM specification under development is in parallel to existing COM Express efforts. This effort is intended to complement rather than be a replacement for COM Express The subcommittee will develop a next-generation COM standard and an accompanying Carrier Design Guide. The new specification is expected to support two different module types: one for high-performance computing, the other for embedded computing. Initial plans include incorporating a new high-speed connector able to support existing and future interfaces such as PCI Express Gen 5, and 100/200 Gbit Ethernet. The specification will target medium to high-performance server-class processors.

Key COM-HPC Goals:

  • Support for PCIe Gen 5.0 (32 Gb/s)
  • 64 PCIe Lanes
  • 25 Gbit Ethernet per signal pair to support 100 Gbit Ethernet
  • Update of other interfaces to latest technology levels

The goal is to have specifications ratified in early 2020. The team has elected Christian Eder of congatec as committee chair. Kontron’s Stefan Milnor is the technical editor and Dylan Lang of Samtec is the secretary.

“COM-HPC will become a very high-performance module specification,” said committee chair Christian Eder. “It is not a replacement for COM Express; it extends the computer modules to a completely new level. It will serve as a transition from Computer-On-Module to Server-On-Module.”

So far, this initiative includes twenty active member participating companies: ADLINK, Advantech, Amphenol, Bielefeld University, congatec, Elma, Emerson, ept, FASTWEL, HEITEC, Intel, Kontron, MEN Mikro, MSC Technologies, N.A.T., Samtec, SECO, TE Connectivity, Trenz Electronic and VersaLogic.

PICMG | www.picmg.org

 

Processing-In-Memory Technology Targets Next-Gen AI Chips

Renesas Electronics announced it has developed an AI accelerator that performs CNN (convolutional neural network) processing at high speeds and low power to move towards the next generation of Renesas embedded AI (e-AI), which will accelerate increased intelligence of endpoint devices. A Renesas test chip featuring this accelerator has achieved the power efficiency of 8.8 TOPS/W, which the company claims is the industry’s highest class of power efficiency. The Renesas accelerator is based on the processing-in-memory (PIM) architecture, an increasingly popular approach for AI technology, in which multiply-and-accumulate operations are performed in the memory circuit as data is read out from that memory.

To create the new AI accelerator, Renesas developed the following three technologies. The first is a ternary-valued (-1, 0, 1) SRAM structure PIM technology that can perform large-scale CNN computations. The second is an SRAM circuit to be applied with comparators that can read out memory data at low power. The third is a technology that prevents calculation errors due to process variations in the manufacturing.

Together, these technologies achieve both a reduction in the memory access time in deep learning processing and a reduction in the power required for the multiply-and-accumulate operations. As a result, the new accelerator achieves the industry’s highest class of power efficiency while maintaining an accuracy ratio more than 99% when evaluated in a handwritten character recognition test (MNIST).

Renesas presented these results on June 13, at the 2019 Symposia on VLSI Technology and Circuits in Kyoto, Japan, June 9-14, 2019. Renesas also demonstrated real-time image recognition using a prototype AI module in which this test chip, powered by a small battery, was connected with a microcontroller, a camera, other peripheral devices and development tools at the demonstration session.

Until now, the PIM architecture was unable to achieve an adequate accuracy level for large-scale CNN computations with single-bit calculations since the binary (0,1) SRAM structure was only able to handle data with values 0 or 1. Furthermore, process variations in the manufacturing resulted in a reduction in the reliability of these calculations, and workarounds were required. Renesas has now developed technologies that resolve these issues and will be applying these, as a leading-edge technology that can implement revolutionary AI chips of the future, to the next generation of e-AI solutions for applications such as wearable equipment and robots that require both performance and power efficiency.

Renesas Electronics | www.renesas.com

Multi-Channel RF Converter ICs Meet Wireless Carrier Needs

Analog Devices has introduced a mixed-signal front-end (MxFE) RF data converter platform designed to meet the performance needs for a range of wireless equipment such as 4G LTE and 5G millimeter-wave (mmWave) radios. ADI’s new AD9081/2 MxFE platform allows system developers to install multiband radios in the same footprint as single-band radios, which as much as triples call capacity available in today’s 4G LTE base stations. With a 1.2 GHz channel bandwidth, the new MxFE platform also enables wireless carriers that are adding more antennas to their cell towers to meet the higher radio density and data-rate requirements of emerging mmWave 5G.

The AD9081 and AD9082 MxFE devices integrate eight and six RF data converters, respectively, which are manufactured using 28 nm CMOS process technology. Both MxFE options achieve the industry’s widest instantaneous signal bandwidth (up to 2.4 GHz), which simplifies hardware design by reducing the number of frequency translation stages and relaxing filter requirements. This new level of integration addresses the space constraints of wireless device designers by lowering chip count and yielding a 60 percent reduction in printed-circuit-board (PCB) area compared to alternative devices.

By shifting more of the frequency translation and filtering from the analog to the digital domain, the AD9081/2 provides designers with the software configurability to customize their radios. The new multi-channel MxFE platform meets the needs of other wide-bandwidth applications in 5G test and measurement equipment, broadband cable video streaming, multi-antenna phased array radar systems and low-earth-orbit satellite networks.

The MxFE platform processes more of the RF spectrum band and embeds DSP functions on-chip to enable the user to configure the programmable filters and digital up and down conversion blocks to meet specific radio signal bandwidth requirements. This results in a 10X power reduction compared to architectures that perform RF conversion and filtering on the FPGA, while freeing up valuable processor resources or allowing designers to use a more cost-effective FPGA.

The AD9081 is priced at $1,487 (1,000s) and the AD9082 at $1,500. Both will be available for sampling in September 2019.

Analog Devices | www.analog.com

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.

Already a Circuit Cellar Newsletter subscriber? Great!
You’ll get your
Embedded Boards newsletter issue tomorrow.

Not a Circuit Cellar Newsletter subscriber?
Don’t be left out! Sign up now:

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

July has a 5th Tuesday . That’s means we’re giving you an extra Newsletter: PCB Design! (7/30) The process of PCB design is always facing new complexities. Rules-based autorouting, chips with higher lead counts and higher speed interconnections are just a few of the challenges forcing PCB design software to keep pace. This newsletter updates you on the latest happenings in this area.

Analog & Power. (8/6) This newsletter content zeros in on the latest developments in analog and power technologies including DC-DC converters, AC-DC converters, power supplies, op amps, batteries and more.

Microcontroller Watch (8/13) 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. (8/20) 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.

August (issue #349) Circuit Cellar Article Materials

Click here for the Circuit Cellar article code archive

p.6: Automating the Art of Toast: With a Side of Raspberry Pi, By Katie Bradford and Michael Xiao

References:
[1] A small, portable computer. Specifically the Raspberry Pi Zero W, a wireless enabled computer with the smallest form factor for Pis yet, was used in this project https://www.raspberrypi.org/

[2] Using the small PIC32 breakout board provided by ECE4760 course, found here http://people.ece.cornell.edu/land/courses/ece4760/PIC32/target_board.html

[3] Supported by CECOMINOD012186 motor driver boards, complete with voltage regulation and headers.  Qunqi part number MK-050-2.

Additional Information

Website: http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2018/mfx2_keb278/mfx2_keb278/mfx2_keb278/index.html

Video 1: https://www.youtube.com/watch?v=zUwJVrSkh3M

Video 2: https://www.youtube.com/watch?v=gYBhZNorL6M

Adafruit | www.adafruit.com
Microchip Technology | www.microchip.com
Raspberry Pi | www.raspberrypi.org
Sparkfun | www.sparkfun.com
STMicroelectronics | www.st.com

 


p.12: Build an RGB LED Controller: Using Parallel FET Dimming, By Dirceu R. Rodrigues, Jr.

Component List

Resistors

R1, R10, R12, R14 = 10 kΩ

R2, R3, R4, R5, R6, R7, R8 = 390 Ω

R9, R11, R13 = 51 Ω

R15, R19, R20, R21 = 39 kΩ

R16 = 47 Ω

R17 = 4.7 kΩ

R18 = 2.2 kΩ

R22 = 0.33 Ω (Rs)

Capacitors

C1, C3 = 0.1 µF

C2 = 0.33  µF

C4 = 47 µF

C5 = 1 µF

Inductor

L1 = 180 µH (Pulse P0465)

Semiconductors

REG1 =  LT7805CV linear regulator

U1 =  ATmega8 microcontroller (my MYK2 module)

U2 =  ZXLD1350 350 mA LED driver

IR1 = AX-1838HS IR receiver

D1 = ZLSS1000 diode

DI1 = Seven segment display

LED1, LED2, LED3 = Power RGB LED 350 mA/3 W

Q1 = BC848 NPN Transistor

M1, M2, M3 = IRF7317 double power MOSFET

Miscellaneous

Y1 = Crystal 16 MHz

J1 = Power jack

S1 = SPST slide switch

S2 = Push button

Diodes | www.diodes.com
Microchip Technology | www.microchip.com
MCS Electronics | www.mcselec.com

 

p. 20: Building a Twitter Emote Robot: Reactions in Real Time, By Ian Kranz, Nikhil Dhawan and Sofya Calvin

References
[1]  Primack, Brian A et al. “Social Media Use and Perceived Social Isolation Among Young Adults in the U.S” American journal of preventive medicine vol. 53,1 (2017): 1-8.
[2] 18-bit color TFT
Adafruit Inc. | www.adafruit.com
[3] Twitter Python Library
Tweepy | www.tweepy.org
[4] Emotion Analyzer
ParallelDots | www.paralleldots.com
[5] Bluetooth HC-05
DSD Tech | www.dsdtech-global.com
[6] Pic32 PCB
Sean Carroll | people.ece.cornell.edu/land
[7] Peripheral Device Library
Bruce Land | people.ece.cornell.edu/land
[8] Modified Protothreads Library
Syed Tahmid Mahbub | tahmidmc.blogspot.com

 

Adafruit | www.adafruit.com
DSD Tech | www.dsdtech-global.com
MathWorks | www.mathworks.com
Microchip Technology | www.microchip.com
ON Semiconductor | www.onsemi.com
ParallelDots | www.paralleldots.com

 

Watch the video of the TweetBot project here:

 

p. 26: Understanding the Role of Inference Engines in AI: Benchmarks and Batching, By Geoff Tate

Reference
[1] Artificial Intelligence
https://semiengineering.com/knowledge_centers/artificial-intelligence/

Flex Logix Technologies | www.flex-logix.com

 

p.30: Portable Digital Synthesizer: Music Using an MCU, By T.J. Hurd and Ben Roberge

References:
[1] https://www.microchip.com/wwwproducts/en/PIC32MX250F128B
[2] http://people.ece.cornell.edu/land/courses/ece4760/PIC32/target_board.html
[3] https://www.adafruit.com/product/1010
[4] https://cdn-shop.adafruit.com/datasheets/pec11.pdf
[5] http://people.ece.cornell.edu/land/courses/ece4760/PIC32/Microchip_stuff/port_expander.pdf
[6] http://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf
[7] https://www.adafruit.com/product/1480
[8] http://dunkels.com/adam/pt/index.html
[9] https://www.analog.com/en/analog-dialogue/articles/all-about-direct-digital-synthesis.html
[10] https://en.wikipedia.org/wiki/Frequency_modulation_synthesis
[11] https://www.wikiaudio.org/adsr-envelope/
[12] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf
[13] https://www.best-microcontroller-projects.com/rotary-encoder.html
[14] https://www.soundonsound.com/techniques/optimising-latency-pc-audio-interface#7

Adafruit | www.adafruit.com
Autodesk | www.autodesk.com
Microchip Technology | www.microchip.com
Monoprice | www.monoprice.com

Watch the video of the Portable Digital Synthesizer project here:

 

 

p.38: IC Solutions Rev Up for Next Gen Auto Designs: MCUs, Analog ICs and More, By Jeff Child

p.45: Display Solutions Enhance Embedded Designs: System-Level Functionality, By Jeff Child

p.48: PRODUCT FOCUS: Tiny Embedded Boards: Petite Processing, by Jeff Child



p.52: EMBEDDED IN THIN SLICES: Bluetooth Mesh (Part 4): Models and Re-Use, By Bob Japenga

References:
[1] For Licensing rights https://upload.wikimedia.org/wikipedia/commons/2/2b/Osi-model.png
[2] Created by Bob Japenga
[3] Created by Bob Japenga


p.58: THE DARKER SIDE: The Fundamentals of Fuseology: Purposeful Protection, By Robert Lacoste

References
[1]  Fuses https://en.wikipedia.org/wiki/Fuse_(electrical)
[2] IEC60269
Low-voltage power fuses
https://en.wikipedia.org/wiki/IEC_60269
[3] Fuseology
Littelfuse
https://m.littelfuse.com/~/media/automotive/catalogs/littelfuse_fuseology.pdf

IEC 60127-2:2014
Miniature fuses – Part 2: Cartridge fuse-links
https://webstore.iec.ch/publication/814

Fuse Technology
Bussmann
http://www1.cooperbussmann.com/pdf/201de5b7-c22d-4b7b-814b-f803ab96cd83.pdf

Fuse glass 2 A 250 VAC 5 x 20 mm
Littelfuse ref 0218002.HXP

AIM-TTi | www.aimtti.com
Keysight | www.keysight.com
Littelfuse | www.littelfuse.com
TDK-Lambda | www.tdk-lambda.com


p.64: FROM THE BENCH: Watt’s Up with LEDs?: Efficiency Put to the Test, By Jeff Bachiochi

References:
[1]  Luxeon heatsink calculator.
 https://support.luxeonstar.com/hc/en-us/articles/360022625174-How-do-I-determine-what-size-of-heat-sink-I-need-Includes-heat-sink-calculator-

 

 

www.westinghouselighting.com/color-temperature.aspx
www.ledwatcher.com/light-measurements-explained/#light-meter-apps

www.ohmite.com/assets/docs/sink_s.pdf

‘Light Meter’ by Doggo Apps or ‘Lux Meter’ by My Mobile Tools Dev

3 W High-Power LEDs

Addicore

 

Addicore | www.addicore.com
On Semiconductor | www.onsemi.com
Texas Instruments | www.ti.com

p.72: THE CONSUMMATE ENGINEER: Energy Monitoring (Part 3): Natural Gas and More, By George Novacek

References:

  1. George Novacek, Humidity Sensors, Circuit Cellar Issue 339
  2. Silicon Labs Si7006-A20 http://www.silabs.com/documents/public/data-sheets/Si7006-A20.pdf
  3. Adafruit Industries https://www.adafruit.com/
  4. Universal Solder https://universal-solder.ca/
  5. SparkFun Electronics https://www.sparkfun.com/
  6. Circuit Cellar #288 WWVB Clock Revisited by George Novacek

 

p.79: The Future of IoT Standards: Unlock IoT: What’s West of Westeros?, By Cees Links

References
[1] Golden Mousetrap Lifetime Achievement Award
[2] Wi-Fi NOW Hall of Fame.

Qorvo | www.qorvo.com

 

Updated COMe Board Sports 9th Gen Intel Processors, 128 GB RAM

Kontron is providing the its COMe-bCL6 COM Express basic Type 6 form factor (125 mm x 95 mm) board equipped with Intel 9th Gen processors. With up to four memory sockets it enables a maximum memory expansion of up to 128 GB. The board is available in different processor versions. All versions can be equipped with up to 128 GB non-ECC/ECC DDR4 memory.

The Intel Optane system accelerator ensures fast data transfer from and to high-capacity mass storage devices. NVMe SSD also supports what is currently the fastest storage technology in a very compact package. Thanks to USB 3.1 support with up to 10 Gbps and USB Type-C support, twice the bandwidth (compared to USB 3.0) can be achieved for fast data transfers.

The COMe-bCL6 is well suited as a successor for existing solutions, because it takes over their pin out and feature implementation. Typical applications include communication, digital signage, professional gaming and entertainment, medical imaging, surveillance and security, industrial edge or server applications, as well as industrial plant, machine and robot control, both at shop floor level and from the control room. The rugged variants of the COMe-bCL6 meet the particular demands of the defense, transportation and avionics sectors by offering an extended feature set and industrial temperature range from -40°C to +85°C.

The COMe-bCL6 supports the Kontron APPROTECT security solution based on Wibu-Systems CodeMeter. In addition, Kontron APPROTECT Licensing enables the realization of new business models such as pay-per-use or time-based test versions.

Kontron | www.kontron.com

Embedded Solutions Enable Smarter Railway Systems

Computing, Connectivity and Control

Railway systems keep getting more advanced. On both the control side and passenger entertainment side, embedded computers play critical roles. Railway systems need sophisticated networking, data collection and real-time control—all while meeting safety standards.

By Jeff Child, Editor-in-Chief

There’s no doubt that railway systems represent one of the most dynamic segments of embedded computing design. There’s a lot for embedded systems to do aboard trains—ensuring both safety and precise control for the train, but also for the increasingly sophisticated entertainment systems installed on today’s modern trains.

Meanwhile, trains are evolving into moving Internet-of-Things (IoT) platforms, as system developers strive to leverage the many benefits of data collection and passenger monitoring. Even embedded artificial intelligence (AI) is finding its way into the mindshare of railway system developers.

Figure 1
An overview EN 50155, ISO 7637-2 and IRIS certified electronics that are embedded into trains (and buses) for control, supervision, communication, passenger information, security and testing.

Exemplifying these trends, MEN Micro is a leading example of an embedded computer vendor deeply immersed in railway system technology development. Among its offerings are its line of EN 50155, ISO 7637-2 and IRIS certified electronics that are embedded into trains (and buses) for control, supervision, communication, passenger information, security and testing. Figure 1 shows an overview of the MEN’s solutions along those lines. EN 50155 is one of a handful of standards targeted specifically for railway systems. Table 1 shows of summary of these standards.

TABLE 1
Shown here is a summary of the key certifications for embedded computers for railway systems. (Source: Assured Systems).

DIN-Rail Mounting

In January, MEN Micro introduced the MC50M, its latest modular computer for DIN rail mounting. To clarify, “rail” in this context is referring not to railroad rails but rather to the metal DIN rail, a standard type of mounting used in industrial control equipment inside equipment racks. MEN’s DIN rail concept is designed for flexible configuration of module combinations and is suitable for embedded IoT applications in various markets. DIN rail mounting (35 mm) is standard. Wall and 19’’ rack mounting are possible using adaption brackets.

The EN 50155-compliant box is based on Intel’s Atom E3900 series with low power dissipation and scalability in performance and memory. The modular expansion concept makes the DIN rail family a cost-effective and flexible solution. For memory, the system provides up to 8 GB of DDR3 SDRAM and an M.2 NVMe slot for mass storage. The box embeds a Trusted Platform Module for security and for I/O the MC50M provides Gbit Ethernet, USB 3.0, RS-232, R-S485/422 and DisplayPort. Input voltage is 24 VDC nominal with ignition and it supports a full-range of PSUs from 9 VDC to 60 VDC. Operating temperature is -55°C to +70°C.

According to MEN Micro, the MC50M is well suited for transportation functions such as security gateways, predictive maintenance, CCTV, ticketing systems or as a diagnostic server. The MC50M can be used as a stand-alone product or in combination with a range of pre-fabricated extension modules, providing additional features and short delivery times.

Extension modules can provide application-specific functions such as wireless communication (LTE advanced, WLAN, GNSS), MVB, CAN bus or other I/Os. A removable storage shuttle supports the integration of one or two 2.5” SATA hard disks/SSDs. The wide range PSU allows isolated power supply from 24 VDC to 110 VDC nominal and extends the entire system to EN 50155 compliance.

The board management controller provides increased reliability and reduces downtime. The Trusted Platform Module supports security and encryption features. With an ignition switch for remote startup and shutdown control, the platform provides additional energy saving features. The aluminum housing with cooling fins ensures conductive cooling and fanless operation. The MC50M has no moving parts, so it can be operated maintenance-free. The long-term availability of 15 years from product launch minimizes life cycle management by making the MC50M available for at least that period.

Security and Safety

Security and safety go hand-in-hand when it comes to railway computing systems. With that in mind, in April Kontron and SYSGO jointly started the development of an integrated platform for safety-critical railway solutions based on Kontron’s SAFe-VX hardware. Their aim was to provide system integrators with a solid and flexible basis for certifiable applications in trains and signaling.

Kontron’s hardware is already used in many railway systems and has been certified up to SIL-4, the highest level of the IEC 61508 standard for functional safety of electronic systems. …

Read the full article in the July 348 issue of Circuit Cellar
(Full article word count: 3856 words; Figure count: 8 Figures.)

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Bidirectional Current Sense Amplifier Features PWM Rejection

Maxim Integrated has introduced the MAX40056, a bidirectional current sense amplifier with patented pulse-width modulation (PWM) rejection. This high speed, wide-bandwidth amplifier extends Maxim’s family of precision, high-voltage current sense amplifiers into motor control applications.

Creating a motor control system requires precise current sensing and measurement of motor winding currents, says Maxim. A commonly used approach is to infer winding currents by performing ground or supply referenced measurements in the bridge circuit. Direct winding current measurement is a simpler and more accurate method, but the implementation is challenging due to the high common mode swing of the PWM signal. Adoption of this approach has been limited by poor PWM rejection and slow settling speed of existing solutions.

MAX40056 rejects PWM slew rates of greater than 500 V/µs and settles within 500 ns to provide 0.3 percent accurate, full-scale winding current measurement. The patented PWM rejection scheme achieves 4 times faster settling time than competitive offerings, allowing motor control designers to increase drive frequency or decrease minimum duty cycle without sacrificing measurement accuracy. Higher PWM frequency smooths out the current flow and reduces torque ripple, resulting in more efficient motor operation.

Accurate winding current measurement at low duty cycle helps reduce or virtually eliminate vibration when the motor is running at a slow speed. MAX40056 has a wide common mode voltage range of -0.1 V to +65 V and a protection range of -5 V to 70 V to ensure the inductive kickback does not damage the IC. With bi-directional sensing capability, it is well suited for DC motor control, base station, datacenter, battery stack and many other applications which require precise current measurements in noisy environments.

The MAX40056 is available at Maxim’s website for $1.19 (1000-up, FOB USA), also available from authorized distributors. The MAX40056EVKIT evaluation kit is available for $69.

Maxim Integrated | www.maximintegrated.com

3.5-Inch SBC Serves up Coffee Lake-H Processors

COMMELL has unveiled its LE-37M 3.5-inch SBC based on Intel 8th generation Coffee Lake-H Core processor family. The Coffee Lake-H 8th generation Intel Core i7/i5/i3 processors provides higher computing and graphics performance but at a similar power dissipation level to the previous 7th generation. The LE-37M SBC will be offered with two processor variants: LE-37M5 comprised of Core i5-8400H Max Turbo up to 4.2 GHz with 4 CPU cores, 8-thread and 45 W TDP, LE-37M7 comprise of Core i7-8850H Max Turbo up to 4.3 GHz with 6 CPU cores, 12-thread and 45 W TDP.

The LE-37M 3.5-inch SBC is designed for the 8th generation Intel Core H-series processors in the FCBGA1440 and accompany with Intel QM370 Chipset. DDR4 memory is supported up to a total of 32 GB (DDR4 SO-DIMM 2,666 MHz). The SBC is based on powerful Intel UHD Graphics that provides high-end media and graphics capabilities, allows triple independent display with 4k resolution each, and comes with hardware-based video encoding and decoding up to 4k. The LE-37M features VGA, LVDS, HDMI and one DisplayPort outputs to provide its advanced solutions for imaging, machine vision and infotainment applications, medical and gaming machine applications.

The SBC provides lots of features including high-speed data transfer interfaces such as 4 x USB3.1 Gen2 and 2 x SATAIII, equipped with dual Gbit Ethernet Intel I210 and I219-LM (iAMT 11.0 support), and comes with PS/2 port, 2 x RS232 and 2 x RS232/422/485, 4 x USB 2.0, Realtek High Definition Audio, 1 x SMBus, 1 x 8 bit GPIO, 1 x MiniPCIe (support mSATA), 1 x M.2 (Key E). The operating voltage of LE-37M is from 9 V to 35 V DC power supply.

COMMELL | www.commell.com.tw