High-Performing, Intelligent Wireless Transceiver Module

The RF Solutions high-performance ZETA module was recently updated to include a simple SPI and UART interface. The ZETAPLUS module doesn’t require external components, which means a fast and effective plug-and-play setup.

ZETAPLUS

Available on 433-, 868-, and 915-MHz frequencies, the module is easy to set up and you’ll be sending and receiving data quickly. Furthermore, you’ll find it easy to create networks of ZETAPLUS modules or point-to-point links without the need for time-consuming register configuration.

With an impressive 2-km range, the ZETAPLUS is well-suited for sensor networks, sleepy nodes, and numerous other telemetry, control, and Internet of Things (IoT) applications.

RF Solutions | www.rfsolutions.co.uk

FCC-Certified AMB2621 Bluetooth Smart Module

AMBER Wireless’s AMB2621 Bluetooth Smart module is certified for the United States and Canadian markets (Code of Federal Regulations, Title 47, Telecommunication Part 15 – Radio Frequency Devices). Manufacturers that use the wireless module in their products can gain time and cost benefits as a result because they don’t have to have them specifically certified with the Federal Communications Commission (FCC).

Amber Wireless

The certifications for the AMB2621 module demonstrate the following: personal safety isn’t at risk, there’s good immunity against electromagnetic interference, and the radio spectrum is used efficiently. As a result, manufacturers can bring their devices to market quicker and without their own FCC certification. A simple reference on the device label is sufficient (i.e., FCC-ID R7TAMB2621 is integrated).

The AMB2621’s features, specs, and benefits:

  • 2.4 GHz BLE radio module
  • 11 × 8 × 1.8 mm size
  • Compliant with the Bluetooth Smart 4.2 Standard
  • Offered with or without an integrated antenna
  • Expands existing products with a BLE interface without having to be adapted in advance..

AMBER Wireless | www.amber-wireless.de

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 Bluetooth 5-Ready SoC Offers Increased Range, Bandwidth, & Security

Nordic Semiconductor’s new Bluetooth 5-ready nRF52840 SoC is well suited for smart home, advanced wearables, and industrial IoT applications. In addition to supporting 802.15.4, it’s capable of delivering Bluetooth low energy (BLE) wireless connectivity with up to 4× the range or 2× the raw data bandwidth (2 Mbps) compared with the BLE implementation of Bluetooth 4.2Nordic nRF52840

The nRF52840 SoC’s features, specs, and benefits:

  • Features a 64-MHz, 32-bit ARM Cortex M4F processor employed on Nordic’s nRF52832 SoC
  • A new radio architecture with on-chip PA boosting output power considerably, and extending the link budget for “whole house” applications, a doubling of flash memory to 1 MB, and a quadrupling of RAM memory to 256 KB
  • Support for Bluetooth 5, 802.15.4, ANT, and proprietary 2.4-GHz wireless technologies
  • A full-speed USB 2.0 controller
  • A host of new peripherals (many with EasyDMA) including a quad-SPI
  • Operates from power supplies above 5 V  (e.g., rechargeable battery power sources)
  • Incorporates the ARM CryptoCell-310 cryptographic accelerator offering best-in-class security for Cortex-M based SoCs. Extensive crypto ciphers and key generation and storage options are also available.

Nordic released the S140 SoftDevice and associated nRF5 SDK with support for Bluetooth 5 longer range and high throughput modes in December 2016. Engineering samples and development kits are now available. Production variants of the nRF52840 will be available in Q4 2017.

Source: Nordic Semiconductor 

Multi-Protocol Sub-GHz Wireless Transceiver Platform

NXP Semiconductors recently added the OL2385 family sub-GHz wireless transceivers to its low-power microcontroller and 2.4 GHz portfolio for Internet of Things (IoT) applications. Based on a PIN-to-PIN compatible, sub-GHz transceiver hardware platform, the OL2385 supports multiple wireless protocols  (e.g., Sigfox, W-MBus powered by Xemex, and ZigBee IEEE 802.15.4).

With a two-way RF channel and common modulation schemes for networking applicatios, the OL2385 transceivers cover a wide range of frequency bands from 160 to 960 MHz. In addition, extended range radio operation is enabled with high sensitivity up to –128 dBm. Operation in congested environments is enhanced with 60 dB at 1 MHz of blocking performance and 60 dB of image rejection.

Platform features include: 14-dBm Tx output power compliant with ETSI limits; typical 29-mA transmit power consumption at full output power; less than 11 mA receive power consumption; excellent phase noise of –127 dBc at 1 MHz in the 868- and 915-MHz band for flexibility with external power amplifiers; and Japanese ARIB T108 standard compliant.

The OL2385 platform samples and development boards with SIGFOX are currently available. Mass production of preprogrammed parts are scheduled for the end of Q4 2017.

Source: NXP Semiconductors

Analog Tips & Tricks

Are you looking for ways to improve your analog and RF circuitry? Engineer Ed Nisley provides a few tips for getting started. He shows you how easy it is to take your PCB wiring skills to the next level. Who knows, your digital projects just might improve too.

Circuit Cellar has always attracted readers who enjoy building gizmos, both at work and for their own use. My December 2004 column, “Building Boxes,” prompted enough comments and suggestions regarding additional techniques that I decided a follow-up was in order.

Although these tricks are designed to improve your analog and RF circuitry, even your digital projects will benefit, because digital is just analog with the gain cranked way up. You’re sure to find at least one technique that will make your next project work better.

I wire most of my projects on PCBs built in my basement shop, using a process that produces both circuit documentation and reasonably high-quality hardware without too much effort. I’ve come up with some tricks that should help you get good results too.

I use CadSoft’s EAGLE schematic capture and board layout software, which runs on Windows, Linux, and Mac OS X (www.cadsoftusa.com). The free version can handle most of the circuits in this column, and the Standard version is reasonably priced. EAGLE is perfectly stable on my SuSE Linux 9.2 desktop system. The board layout program can produce output files in nearly any format, including the Gerber files used in board production shops. I save the output for each layer as a Postscript file, and then import the files into the GNU Image Manipulation Program (GIMP) image-editing program at 600 dpi.

The top image is the top copper layer from an EAGLE board design. The bare board shows several flaws, but the one on the bottom came out fine. The ruler scales are 0.050″ vertically and 1 mm horizontally. The board has extremely small features!

The top image is the top copper layer from an EAGLE board design. The bare board shows several flaws, but the one on the bottom came out fine. The ruler scales are 0.050″ vertically and 1 mm horizontally. The board has extremely small features!

The top image in Photo 1 shows the copper plane pattern for the charge pump LED power supply I described in my April 2005 column. I panelize them with the GIMP to produce a single image with multiple patterns in a rectangular grid. Because all this happens digitally, there’s no loss of resolution and no smudges. I then print the image through an HP LaserJet 1200 on a sheet of toner-transfer film from either Pulsar (www.pulsar.gs) or Techniks (www.techniks.com). It turns out that toner contains a thermoplastic that both adheres to bare copper and resists the etching chemical solution.

Because most of my boards are extremely small, they don’t fill a complete sheet of the toner-transfer film even after I panelize them. I print a sheet of paper, tape a square of film that’s approximately 1″ larger than the patterns atop them, and then run the paper through the printer again. The adhesive on cheaper tapes tends to melt at laser printer temperatures, so use good tape and monitor your results. Put a single strip on the leading edge of the toner-transfer film to allow the paper and film to shift slightly as they pass through the fuser rollers.

This article first appeared in Circuit Cellar 181. You can read the entire article here.

Ed Nisley is an electrical engineer, author, and long-time Circuit Cellar columnist living in Poughkeepsie, NY. His column “Above the Ground Plane” appears in Circuit Cellar every other month. You can contact him at ed.nisley@pobox. com. Write “Circuit Cellar” in the subject line to avoid spam filters.

ZULU2 Radio Module

RF Solutions recently released its ZULU2 radio module range. Featuring a telemetry module, modem module, and a firmware-free module, the new range’s functionality is on par with its predecessor, with the advantage that no external components are required to provide a complete RF solution. RF Solutions ZULU2The new range includes:

  • ZULU2-M: A highly integrated RF modem and intelligent controller with a simple interface to the host controller. It handles all RF data communications automatically and without any requirement from the user.
  • ZULU2-T: Telemetry module providing a reliable transceiver based remote switch with up to 2km range. Each unit is supplied ready to operate, once paired with another, a remote control system is created.
  • ZULU2: A hardware platform module containing a SiLabs RF Transceiver and Processor allowing the user to programme the device to suit their own requirements. With no firmware supplied by RF Solutions, this would appeal to somebody with a confident programming ability.

The 25 mm × 11 mm smart modules can achieve a range of 2 km. License-free and operating on the 868- or 915-MHz frequency bands, the ZULU-2 range is available in surface-mount and dual-inline options, making it a good option for applications such as remote control, security, and data logging.

Source: RF Solutions

Tiny M10578 Modules Add GPS and GNSS to Small Devices and Wearables

Antenova recently released two new modules for GPS and GNSS. The M10578-A2 and M10578-A3 provide an easy drop-in receiver solution, which is a useful way to add location capability to very small consumer devices.Antenova M10578-A2

The modules—based on the MediaTek processor—both measure 9 × 9 × 1.8 mm with low current consumption, which makes them suitable for smaller portable devices, such as smart watches, navigation devices, OBD II modules, asset tracking, personal safety, and sports cameras.

The M10578-A2 module operates with GPS, with a 1-to-5-Hz update rate. The M10578-A3 operates with GPS, GLONASS, BEIDOU, and Gallileo with an update rate of 1 to 10 Hz. Included is internal self-generated orbit prediction that uses two GNSS systems simultaneously to give a faster time to fix and a second high-quality low noise amplifier (LNA) to boost low powered satellite signals. Both modules are pin compatible. As for the antenna function, Antenova offers the small Sinica SR4G008 GNSS antenna. Built on high-grade FR4 substrates with a high density, the modules’ multilayered design places the critical RF functions in the best position for location finding and performance.

Source: Antenova

The GAMMA Smart Module

RF Solutions’s GAMMA smart plug-in RF module offers incredible range and simple setup. You can it as a remote control, data modem, or a bidirectional switch.RF Solutions GAMMA

The latest addition to RF Solutions’s SMART Radio family, the module uses spread-spectrum technology and extensive algorithm enhancements to achieve 16-km range. With eight switch inputs or eight digital outputs, you can use two GAMMA’s modules as a receiver/transmitter remote control. Alternatively, you can set up a transceiver between two GAMMAs, where outputs on the receiving GAMMA will follow the inputs on the transmitting GAMMA.

Ready to use right out of the box, the GAMMA works either on its own or as a part of an existing system. It’s available in 868 and 915 MHz (with an option of SMT or SIL), you can use the GAMMA for a variety of applications.

Source: RF Solutions

GaN Devices for Mobile Base Station Transmitters

Infineon Technologies recently introduced its first devices in a family of Gallium Nitride (GaN) on Silicon Carbide (SiC) RF power transistors. The devices enable mobile base station manufacturers to build smaller, more powerful and more flexible transmitters. With higher efficiency, improved power density, and more bandwidth than currently used RF power transistors, the new devices improve the economics of building infrastructure to support today’s cellular networks. Additionally, they will enable the transition to 5G technology with higher data volumes and enhanced user-experience.Infineon-gan-group

The new RF power transistors leverage the performance of GaN technology to achieve ten percent higher efficiency and five times the power density of the LDMOS transistors commonly used today. This translates to smaller footprints and power requirements for the power amplifiers (PA) of base station transmitters in use today, which operate in either the 1.8-2.2 GHz or 2.3-2.7 GHz frequency range. Future GaN on SiC devices will also support 5G cellular bandsup to the 6 GHz frequency range. This roadmap allows Infineon to build on its long-standing expertise and state-of-the-art production technologies for RF transistor technology.

Design flexibility and support for the next-generation of 4G technology are additional benefits of GaN devices for RF power applications. The new devices have twice the RF bandwidth of LDMOS, so that one PA can support multiple operating frequencies. They also have increased instantaneous bandwidth available for transmitters, which lets a carrier offer higher dates using the data aggregation technique specified for 4.5G cellular networks.

Source: Infineon Technologies

RF Direct Conversion Zero-IF, Near Zero-IF and Low-IF Receiver ICs

CML Microcircuits recently released the CMX994A and CMX994E Direct Conversion Receiver (DCRx) ICs. The CMX994A and CMX994E are RF receiver ICs—which feature I/Q demodulators with low-power consumption and high-performance features—are targeted at narrowband and wideband Software Defined Radios (SDR) for wireless data and two-way radio applications. Their design provides the optimum route for high integration, allowing a small RF receiver to be realised with a minimum of external components in zero-IF, near zero-IF and low-IF systems.

The CMX994A and the CMX994E ICs build on the success of the popular CMX994 and are the first devices to use CML’s PowerTrade technology. PowerTrade enables the devices to dynamically balance power consumption and performance characteristics to suit varying operating requirements. Very low power consumption can also be achieved in standby mode whilst looking for an RF signal, using intelligent control of power cycling, phase control and I/Q channel selection.

The CMX994A delivers a very low power DCRx device while the CMX994E also includes the low power mode of the CMX994A but in addition, offers a high performance mode with improved IP3 performance.

The CMX994, CMX994A and CMX994E DCRx ICs offer excellent RF performance, exceptional IP2 from I/Q mixers and are suitable for modulation schemes including: QAM, 4FSK, GMSK and pi/4-DQPSK. Key features of the device include on-chip VCO for VHF applications, on-chip LNA, precision baseband filtering with selectable bandwidths and the smallest PCB area, typically less than 50% of a dual superhet.

The CMX994A and CMX994E are available, operating at 3 to 3.6 V, and come in a Q4 40-pin VQFN package.

Source: CML Microcircuits

Wireless Data Link

In 2001, while working on self-contained robot system called “Scout,” Tom Dahlin and Donald Krantz developed an interesting wireless data link. A tubular, wheeled robot, Scout’s wireless data link is divided into separate boards, one for radio control and another containing RF hardware.

Dahlin and Krantz write:

This article will describe the hardware and software design and implementation of a low-power, wireless RF data link. We will discuss a robotic application in which the RF link facilitates the command and control functions of a tele-operated miniature robot. The RF Monolithics (RFM) TR-3000 chip is the core of the transceiver design. We use a straightforward interface to a PIC controller, so you should be able to use or adapt much of this application for your needs…

Photo 1: The robot measures a little over 4″. Designed for tele-operated remote surveillance, it contains a video camera and transmitter. Scout can hop over obstacles by hoisting its tail spring (shown extended) and quickly releasing it to slap the ground and propel the robot into the air.

Photo 1: The robot measures a little over 4″. Designed for teleoperated remote surveillance, it contains a video camera and transmitter. Scout can hop over obstacles by hoisting its tail spring (shown extended) and quickly releasing it to slap the ground and propel the robot into the air.

The robot, called Scout, is packed in a 38-mm diameter tube with coaxial-mounted wheels at each end, approximately 110-mm long. The robot is shown in Photo 1. (For additional information, see the “Key Specifications for Scout Robot” sidebar.) Scout carries a miniature video camera and video transmitter, allowing you to tele-operate the robot by sending it steering commands while watching video images sent back from Scout. The video transmitter and data transceiver contained on the robot are separate devices, operating at 915 and 433MHz, respectively. Also contained on Scout are dual-axis magnetometers (for compass functions) and dual-axis accelerometers (for tilt/inclination measurement).

Figure 1: For the radio processor board, a PIC16F877 provides the horsepower to perform transceiver control, Manchester encoding, and packet formatting.

Figure 1: For the radio processor board, a PIC16F877 provides the horsepower to perform transceiver control, Manchester encoding, and packet formatting.

Scout’s hardware and software were designed to be modular. The wireless data link is physically partitioned onto two separate boards, one containing a PIC processor for radio control, message formatting, and data encoding (see Figure 1). The other board contains the RF hardware, consisting of the RFM TR3000 chip and supporting discrete components. By separating the two boards, we were able to keep the digital noise and trash away from the radio.

Read the full article.

Utilize Simple Radios with Simple Computers

I ordered some little UHF transmitters and receivers from suppliers on AliExpress, the Chinese equivalent of Amazon.com, in order to extend my door chimes into areas of my home where I could not hear them. These ridiculously inexpensive units are currently about $1 per transmitter-receiver pair in quantities of five, including shipping, and are available at 315 and 433.92 MHz. Photo 1 shows a transmitter and receiver pair.  Connections are power and ground and data in or out.

Photo 1: 315 MHz Transmitter-Receiver Pair (Receiver on Left)

Photo 1: The 315-MHz transmitter-receiver pair (receiver on left)

The original attempt at a door chime extender modulated the transmit RF with an audio tone and searched for the presence of that tone at the receiver with a narrow audio filter, envelope detector, and threshold detector. This sort of worked, but I started incorporating the same transmitters into another project that interfered, despite the audio filter.

The other project used Arduino Uno R3 computers and Virtual Wire to convey data reliably between transmitters and receivers. Do not expect a simple connection to a serial port to work well. As the other project evolved, I learned enough about the Atmel ATtiny85 processor, a smaller alternative to the Atmel ATmega328 processor in the Arduino Uno R3, to make new and better and very much simpler circuits. That project evolved to come full circle and now serves as a better doorbell extender. The transmitters self identify, so a second transmit unit now also notifies me when the postman opens the mailbox.

Note the requirement for Virtual Wire.  Do not expect a simple connection to a serial port to work very well.

Transmitter

Figure 1 shows the basic transmitter circuit, and Photo 2 shows the prototype transmitter. There is only the ATtiny85 CPU and a transmitter board. The ATtiny85 only has eight pins with two dedicated to power and one to the Reset input.

Figure 1: Simple Transmitter Schematic

Figure 1: Simple transmitter schematic

One digital output powers the transmitter and a second digital output provides data to the transmitter.  The remaining three pins are available to serve as inputs.  One serves to configure and control the unit as a mailbox alarm, and the other two set the identification message the transmitter sends to enable the receiver to discriminate among a group of such transmitters.

Photo 2: 315 MHz Transmitter and ATtiny85 CPU

Photo 2: The 315-MHz transmitter and ATtiny85 CPU

When input pin 3 is high at power-up, the unit enters mailbox alarm mode. In mailbox alarm mode, the input pins 2 and 7 serve as binary identification bits to define the value of the single numeric character that the transmitter sends, and the input pin 3 serves as the interrupt input. Whenever input pin 3 transitions from high-to-low or low-to-high, the ATtiny85 CPU wakes from SLEEP_MODE_PWR_DOWN, makes a single transmission, and goes back to sleep. The current mailbox sensor is a tilt switch mounted to the door of the mailbox. The next one will likely be a reed relay, so only a magnet will need to move.

When in SLEEP_MODE_PWR_DOWN, the whole circuit draws under 0.5 µA. I expect long life from the three AAA batteries if they can withstand heat, cold, and moisture. I can program the ATtiny to pull the identification inputs high, but each binary identification pin then draws about 100 µA when pulled low. In contrast, the 20- or 22-MΩ pull-up resistors I use as pull-ups each draw only a small fraction of a microampere when pulled low.

When input pin 3 is low at power-up, the unit enters doorbell extender alarm mode. In doorbell extender alarm mode, the input pins 2 and 7 again serve as binary identification bits to define the value of the single numeric character that the transmitter sends; but in doorbell extender mode, the unit repetitively transmits the identification character whenever power from the door chimes remains applied.

Receiver

Figure 2 shows the basic receiver circuit, and Photo 3 shows the prototype receiver. There is only the ATtiny85 CPU with a 78L05 voltage regulator and a receiver board.

Figure 2: Simple Receiver Schematic

Figure 2: Simple receiver schematic

The receiver output feeds the input at pin 5. The Virtual Wire software decodes and presents the received character. Software in the CPU sends tone pulses to a loudspeaker that convey the value of the identification code received, so I can tell the difference between the door chime and the mailbox signals. Current software changes both the number of beep tones and their audible frequency to indicate the identity of the transmit source.

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Note that these receivers are annoyingly sensitive to power supply ripple, so receiver power must either come from a filtered and regulated supply or from batteries.

Photo 4 shows the complete receiver with the loudspeaker.

Photo 4: Receiver with antenna connections and loudspeaker

Photo 4: Receiver with antenna connections and a loudspeaker

Link Margin

A few inches of wire for an antenna will reach anywhere in my small basement. To improve transmission distance from the mailbox at the street to the receiver in my basement, I added a simple half-wave dipole antenna to both transmitter and receiver. Construction is with insulated magnet wire so I can twist the balanced transmission line portion as in Photo 5. I bring the transmission line out through an existing hole in my metal mailbox and staple the vertical dipole to the wooden mail post. My next mailbox will not be metal.

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

I don’t have long term bad weather data to show this will continue to work through heavy ice and snow, but my mailman sees me respond promptly so far.

Operating Mode Differences

The mailbox unit must operate at minimum battery drain, and it does this very well. The doorbell extender operates continuously when the AC door chime applies power. In order to complete a full message no matter how short a time someone presses the doorbell push button, I rectify the AC and store charge in a relatively large electrolytic capacitor to enable sufficient transmission time.

Photo 6: New PCBs for receive and transmit

Photo 6: New PCBs for receive and transmit

Availability

This unit is fairly simple to fabricate and program your self, but if there is demand, my friend Lee Johnson will make and sell boards with pre-programmed ATtiny85 CPUs. (Lee Johnson, NØVI, will have information on his website if we develop this project into a product: www.citrus-electronics.com.) We will socket the CPU so you can replace it to change the program. The new transmitter and receiver printed circuit boards appear in Photo 6.


Dr. Sam Green (WØPCE) is a retired aerospace engineer living in Saint Louis, MO. He holds degrees in Electronic Engineering from Northwestern University and the University of Illinois at Urbana. Sam specialized in free space and fiber optical data communications and photonics. He became KN9KEQ and K9KEQ in 1957, while a high school freshman in Skokie, IL, where he was a Skokie Six Meter Indian. Sam held a Technician class license for 36 years before finally upgrading to Amateur Extra Class in 1993. He is a member of ARRL, a member of the Boeing Employees Amateur Radio Society (BEARS), a member of the Saint Louis QRP Society (SLQS), and breakfasts with the Saint Louis Area Microwave Society (SLAMS). Sam is a Registered Professional Engineer in Missouri and a life senior member of IEEE. Sam is listed as inventor on 18 patents.

Impedance Matching Matters (EE Tip #145)

RF designers, as well as more and more digital-oriented designers, are used to thinking about impedance matching. But it is very easy to forget it when you are designing a non-RF project. A non-matched circuit will generate power losses as well as nasty reflection phenomena. (Refer to my article, “TDR Experiments,” Circuit Cellar 225, 2009.)

Impedance matching must be managed at the schematic stage, for example, by adding provisional matching pads for all integrated antennas, which will enable you to correct a slightly mis-adapted antenna (see Figure 1).

Figure 1: Impedance matching requirements must be anticipated. In particular, any embedded antenna will surely need manual matching for optimal performance. If you forget to include some area for a matching network like this one on your PCB, you won’t achieve the best performance.

Figure 1: Impedance matching requirements must be anticipated. In particular, any embedded antenna will surely need manual matching for optimal performance. If you forget to include some area for a matching network like this one on your PCB, you won’t achieve the best performance.

Impedance matching is also a PCB design issue. As rule of thumb, you can’t avoid impedance-matched tracks when you are working with frequencies higher than the speed of light divided by 10 times the board size. A typical 10-cm board would translate to a cutoff frequency of 300 MHz. A digital designer would then say: “Cool, my clock is only 100 MHz. No problem!” But a 100-MHz square-ware clock or digital signal means harmonic frequencies in the gigahertz range, so it would be wise to show some concern.

The problem could also happen with very slow clocks when you’re using fast devices. Do you want an example? Last year, one of my colleagues developed a complex system with plenty of large and fast FPGAs. These chips were programmed through a common JTAG link and we ended up with nasty problems on the JTAG bus. We still had issues even when we slowed down the JTAG speed to 100 kHz. So, it couldn’t have been an impedance matching problem, right? Wrong. It was. Simply because the JTAG is managed by the FPGA with the same ultra-fast logic cells that manage your fast logic so with stratospheric skew rates which translated into very fast transitions on the JTAG lines. This generated ringing due to improper impedance matching, so there were false transitions on the bus. Such a problem was easy to solve once we pinpointed it, but we lost some days in between.—Robert Lacoste, CC25, 2013

 

HumDT Wireless UART Data Transceiver

Linx Technologies recently announced the launch of its 11.5 mm × 14.0 mm HumDT wireless UART data transceiver with built-in networking with encryption. Each module can act as one of three components in a wireless network: an access point that controls a network, a range extender (to repeat messages and expand the network’s range, or an end device.

Linx Technologies HumDT

Linx Technologies HumDT

Each access point can connect to up to 50 range extenders and end devices. The access point also supports routing so end devices can communicate with each. The transceiver automatically manages all routing and network maintenance functions.

The 900-MHz HumDT version outputs up to 10 dBm, which results in a line-of-sight range of up to 1,600 m (1 mile), depending on the antenna implementation. The 2.4-GHz version outputs up to 1 dBm, resulting in a line-of-sight range of 100 m (300′).

To aid rapid development, the HumDT Series transceiver is available as part of a newly conceived type of Master Development System. This development kit is designed to assist in the rapid evaluation and integration of the HumDT Series data transceiver modules. The all-inclusive system features several preassembled evaluation boards, which include everything needed to quickly test the operation of the transceiver modules.

At below $9 in volume, the Hummingbird platform is a low-cost complete wideband transceiver with microcontroller module.

Source: Linx Technologies