Toshiba Expands TX04 Range of ARM Cortex-M4F-Based Microcontrollers

Toshiba Electronics Europe has announced a new ARM Cortex-M4F based microcontroller for use in secure systems control. The TMPM46BF10FG expands its existing TX04 range and adds enhanced security features that are well-suited to applications in Internet of Things (IoT) devices, energy management systems, sensor technology, and industrial equipment.Toshiba TMPM46BF10FG

Users of secure communications control systems increasingly require mass memory data for firmware generation management, failure analysis, and high-precision consecutive data storage. The TMPM46BF10FG meets these requirements for high-level security features, such as tamper detection and information concealment. The IC also meets the need to reduce the number of parts on system circuit board by supporting large capacity memory.

Featuring an ARM Cortex-M4F core, with a maximum operating frequency of 120 MHz, the TMPM46BF10FG incorporates 1,024 KB of flash memory and 514-KB SRAM required for secure communications control, four types of security circuits for network communications. The microcontroller also integrates an SLC NAND flash memory controller and 4- and 8-bit error correction circuitry (BCH ECC) that supports memory expansion with 1-to-4-Gb SLC NAND flash memory chips.

To provide additional levels of safety, the IC includes a 16-channel interrupt input and a clock-independent watchdog timer, which operates separately from the system clock, improving the safety of system functions. In the case of a system clock malfunction, the watchdog timer is still capable of detecting errors.

The TMPM46BF10FG incorporates a true random number generator (TRNG: SP800-90C standard) through the combination of a random entropy seed generation (ESG) circuit and Hash-DRGB created by the secure hash processor (SHA) and software program. This meets the robust standards of security that are required in network communications. The hardware based AES encryption/decryption process meets FIPS180-4 and FIPS197 standards and reduces the load on the CPU, in combination with a random seed generation circuit (ESG), and a multiple-length arithmetic (MLA) used to calculate elliptic curves for asymmetric ciphers.

The TMPM46BF10FG features direct memory access (32 channel), a 12-bit AD converter (8 channel), 16-bit timer (8 channel), SPP (3 channel), SIO/UART (4 channel), full UART (2 channel) I2C (3 channel), with an operating voltage of 2.7 to 3.6 V. Housed in an LQFP100 package, the IC measures just 14 mm × 14 mm, with a 0.5-mm pitch.

Samples are now available. Mass production will begin in October.

Source: Toshiba



Quad Bench Power Supply

The need for a bevy of equipment for building and testing presents a problem: how to deliver an adequate power supply while keeping workbench clutter to a minimum. Brian decided to tackle this classic engineering conundrum with a small, low-capacity quad bench power supply.

To the right of the output Johnson posts are the switches that set the polarity of the floating supplies—as well as the switch that disconnects all power supply outputs—while leaving the unit still powered up.

To the right of the output Johnson posts are the switches that set the polarity of the floating supplies—as well as the switch that disconnects all power supply outputs—while leaving the unit still powered up.

In “Quad Bench Power Supply,” Millier writes:

I hate to admit it, but my electronics bench is not a pretty sight, at least in the midst of a project anyway. Of course, I’m always in the middle of some project that, more often than not, contains two or three different projects in various stages of completion. To make matters worse, most of my projects involve microchips, which have to be programmed. Because I use ISP flash memory MCUs exclusively, it makes sense to locate a computer on my construction bench to facilitate programming and testing. To save space, I initially used my laptop’s parallel port for MCU programming. It was only a matter of time before I popped the laptop’s printer port by connecting it to a prototype circuit with errors on it.

Fixing my laptop’s printer port would have involved replacing its main board, which is an expensive proposition. Therefore, I switched over to a desktop computer (with a $20 ISA printer port board) for programming and testing purposes. The desktop, however, took up much more room on my bench.

You can’t do without lots of testing equipment, all of which takes up more bench space. Amongst my test equipment, I have several bench power supplies, which are unfortunately large because I built them with surplus power supply assemblies taken from older, unused equipment. This seemed like a good candidate for miniaturization.

At about the same time, I read a fine article by Robert Lacoste describing a high-power tracking lab power supply (“A Tracking Lab Power Supply,” Circuit Cellar 139). Although I liked many of Robert’s clever design ideas, most of my recent projects seemed to need only modest amounts of power. Therefore, I decided to design my own low-capacity bench supply that would be compact enough to fit in a small case. In this article, I’ll describe that power supply.


Even though I mentioned that my recent project’s power demands were fairly modest, I frequently needed three or more discrete voltage levels. This meant lugging out a couple of different bench supplies and wiring all of them to the circuit I was building. If the circuit required all of the power supplies to cycle on and off simultaneously, the above arrangement was extremely inconvenient. In any event, it took up too much space on my bench.

I decided that I wanted to have four discrete voltage sources available. One power supply would be ground referenced. Two additional power supplies would be floating power supplies. Each of these would have the provision to switch either the positive or negative terminal to the negative (ground) terminal of the ground-referenced supply, allowing for positive or negative output voltage. Alternately, these supplies could be left floating with respect to ground by leaving the aforementioned switch in the center position.

This arrangement allows for one positive and two positive, negative or floating voltage outputs. To round off the complement, I added Condor’s commercial 5-V, 3-A linear power supply module, which I had on hand in my junk box. Table 1 shows the capabilities of the four power supplies.

I wanted to provide the metering of voltage and current for the three variable power supplies. The simultaneous voltage and current measurement of three completely independent power supplies seemed to indicate the need for six digital panel meters. Indeed, this is the path that Robert Lacoste used in his tracking lab supply.

As you can see, there are four power supplies. I’ve included all of the information you need to understand their capabilities.

As you can see, there are four power supplies. I’ve included all of the information you need to understand their capabilities.

I had used many of these DPM modules before, so I was aware of the fact that the modules require their negative measurement terminal to float with respect to the DPM’s own power supply. I solved this problem in the past by providing the DPM module with its own independent power source. Robert solved it by designing a differential drive circuit for the DPM. Either solution, when multiplied by six, is not trivial. Add to this the fact that high-quality DPMs cost about $40 in Canada, and you’ll see why I started to consider a different solution.

I decided to incorporate an MCU into the design to replace the six DPMs as well as six 10-turn potentiometers, which are also becoming expensive. In place of $240 worth of DPMs, I used three inexpensive dual 12-bit ADCs, an MCU, and an inexpensive LCD panel. The $100 worth of 10-turn potentiometers was replaced with three dual digital potentiometers and two inexpensive rotary encoders.

Using a microcontroller-based circuit basically allows you to control the bench supply with a computer for free. I have to admit that I decided to add the commercial 5-V supply module at the last minute; therefore, I didn’t allow for the voltage or current monitoring of this particular supply.


Although there certainly is a digital component to this project, the basic power supply core is a standard analog series-pass regulator design. I borrowed a bit of this design from Robert’s lab supply circuit.

Basically, all three power supplies share the same design. The ground-referenced power supply provides less voltage and more current than the floating supplies. Thus, it uses a different transformer than the two floating supplies. The ground-referenced supply’s digital circuitry (for control of the digital potentiometer and ADC) can be connected directly to the MCU port lines. The two floating supplies, in addition to the different power transformer, also need isolation circuitry to connect to the MCU.

Figure 1 is the schematic for the ground-referenced supply. As you can see, a 24VCT PCB-mounted transformer provides all four necessary voltage sources. A full wave rectifier comprised of D4, D5, and C5 provides the 16 V that’s regulated down to the actual power supply output. Diodes D6, R10, C8, and Zener diode D7 provide the negative power supply needed by the op-amps. …

The ground-referenced power supply includes an independent 5-V supply to run the microcontroller module.

The ground-referenced power supply includes an independent 5-V supply to run the microcontroller module.


As with every other project I’ve worked on in the last two years, I chose the Atmel AVR family for the MCU. In this case, I went with the AT90S8535 for a couple of reasons. I needed 23 I/O lines to handle the three SPI channels, LCD, rotary encoders, and RS-232. This ruled out the use of smaller AVR devices. I could’ve used the slightly less expensive AT90LS8515, but I wanted to allow for the possibility of adding a temperature-sensing meter/alarm option to the circuit. The ’8535 has a 10-bit ADC function that’s suitable for this purpose; the ’8515 does not.

The ’8535 MCU has 8 KB of ISP flash memory, which is just about right for the necessary firmware. It also contains 512 bytes of EEPROM. I used a small amount of the EEPROM to store default values for the three programmable power supplies. That is to say, the power supply will power up with the same settings that existed at the time its Save Configuration push button was last pressed.

To simplify construction, I decided to use a SIMM100 SimmStick module made by Lawicel. The SIMM100 is a 3.5″ × 2.0″ PCB containing the ’8535, power supply regulator, reset function, RS-232 interface, ADC, ISP programming headers, and a 30-pin SimmStick-style bus. I’ve used this module for prototypes several times in the past, but this is the first time I’ve actually incorporated one into a finished project. …

eded to operate the three SPI channels and interface the two rotary encoders come out through the 30-pin bus. As you now know, I designed the ground-referenced power supply PCB to include space to mount the SIMM100 module, as well as the IsoLoop isolators. The SIMM100 mounts at right angles to this PCB; it’s hard-wired in place using 90° header pins. The floating power supplies share a virtually identical PCB layout apart from being smaller because of the lack of traces and circuitry associated with the SIMM100 bus and IsoLoop isolators.

The SIMM100 module has headers for the ISP programming cable and RS-232 port. I used its ADC header to run the LCD by reassigning six of the ADC port pins to general I/O pins.

When I buy in bulk, it’s inevitable that by the time I use the last item in my stock, something better has taken its place. After contacting Lawicel to request a .jpg image of the SIMM100 for this article, I was introduced to the new line of AVR modules that the company is developing.

Rather than a SimmStick-based module, the new modules are 24- and 40-pin DIP modules that are meant to replace Basic Stamps. Instead of using PIC chips/serial EEPROM and a Basic Interpreter, they implement the most powerful members of Atmel’s AVR family—the Mega chips.

Mega chips execute compiled code from fast internal flash memory and contain much more RAM and EEPROM than Stamps. Even though flash programming AVR-family chips is easy through SPI, using inexpensive printer port programming cables, these modules go one step further by incorporating RS-232 flash memory programming. This makes field updates a snap. …

The user interface I settled on consisted of a common 4 × 20 LCD panel along with two rotary encoders. One encoder is used to scroll through the various power supply parameters, and the other adjusts the selected parameter. The cost of LCDs and rotary encoders is reasonable these days. Being able to eliminate the substantial cost of six DPMs and six 10-turn potentiometers was the main reason for choosing an MCU-based design in the first place.

Brian Millier’s article first appeared in Circuit Cellar 149.

ARM MCUs wtith Capacitive Touch Hardware Support for HMI and LIN Applications

Atmel recently announced its next-generation family of automotive-qualified ARM Cortext-M0+-based micrcontrollers with an integrated peripheral touch controller (PTC) for capacitive touch applications. The new SAM DA1 is the first series in this Atmel |SMART MCU automotive-qualified product family, operating at a maximum frequency of 48 MHz and reaching a 2.14 Coremark/MHz.Atmel Corporation SAM DA1

Atmel’s SAM DA1 series is ideal for capacitive touch button, slider, wheel or proximity sensing applications and offers high analog performance for greater front-end flexibility. The new devices are available down to a very compact QFN 5 × 5 mm package with wettable flanks for automated optical inspection.

Eliminating external components and offering more robust features, devices in the SAM DA1 series come with 32 to 64 pins, up to 64 KB of flash memory, 8 KB of SRAM, and 2-KB read-while-write flash memory and are qualified according to the AEC Q-100 Grade 2 (–40° to 105°C).

Key Features of Atmel’s SAM DA1 Series

  • Atmel |SMART ARM Cortex-M0+-based processor
  • 45 DMIPS
  • Vcc 2.7 to 3.63 V
  • 16- to 64-KB Flash; 32 to 64 pins
  • Up to six SERCOM (Serial Communication Interface), USB, I2S
  • Peripheral Touch Controller
  • Complex PWM
  • AEC Q100 Grade 2 Qualified

To accelerate the design development, the ATSAMDA1-XPRO development kit is available to support the new devices. The new SAM DA1 series is also supported by Atmel Studio, Atmel Software Framework and debuggers.

Contact Atmel to sample the SAM DA1 series.

Source: Atmel

New Microcontrollers Feature Advanced Analog & Digital Integration

Microchip Technology recently announced a new family of 8-bit PIC microcontrollers (MCUs) with the PIC16(L)F1769 family, which is the first to offer up to two independent closed-loop channels. This is achieved with the addition of the Programmable Ramp Generator (PRG), which automates slope and ramp compensation, increases stability and efficiencies in hybrid power conversion applications. The PRG provides real-time responses to a system change, without CPU interaction for multiple independent power channels. This allows customers the ability to reduce latency and component counts while improving system efficiency.Microchip PIC16(L)F1769

The PIC16(L)F1769 family includes intelligent analog and digital peripherals, including tristate op-amps, 10-bit ADCs, 5- and 10-bit DACs, 10- and 16-bit PWMs, and high-speed comparators, along with two 100-mA, high-current I/Os. The combination of these integrated peripherals help support the demands of multiple independent closed-loop power channels and system management, while providing an 8-bit platform that simplifies design, enables higher efficiency and increase performance while helping eliminate many discrete components in power-conversion systems.

In addition to power-conversion peripherals, these PIC MCUs have a unique hardware-based LED dimming control function enabled by the interconnections of the Data Signal Modulator (DSM), op amp and 16-bit PWM. The combination of these peripherals creates a LED-dimming engine synchronizing switching control eliminating LED current overshoot and decay. The synchronization of the output switching helps smooth dimming, minimizes color shifting, increases LED life and reduces heat. This family also includes Core Independent Peripherals (CIPs), such as the Configurable Logic Cell (CLC), Complementary Output Generator (COG), and Zero Cross Detect (ZCD). These CIPs take 8-bit PIC MCU performance to a new level, as they are designed to handle tasks with no code or supervision from the CPU to maintain operation, after initial configuration. As a result, they simplify the implementation of complex control systems and give designers the flexibility to innovate. The CLC peripheral allows designers to create custom logic and interconnections specific to their application, reducing interrupt latency, saving code space and adding functionality. The COG peripheral is a powerful waveform generator that can generate complementary waveforms with fine control of key parameters, such as phase, dead-band, blanking, emergency shut-down states, and error-recovery strategies. It provides a cost-effective solution, saving both board space and component cost. The ZCD senses when high voltage AC signal crosses through ground, ideal for TRIAC control functions.

These new 8-bit PIC MCUs provide the capability for multiple independent, closed loop power channels and system management making these products appealing to various power supply, battery management, LED lighting, exterior/interior automotive lighting and general-purpose applications. Along with all these features, the family offers EUSART, I2C/SPI and eXtreme Low Power (XLP) Technology, which are all offered in small form-factor packages, ranging from 14- to 20-pin packages.

The PIC16(L)F1769 family is supported by Microchip’s standard suite of world-class development tools, including the MPLAB ICD 3 (part # DV164035, $199.95) and PICkit 3 (part # PG164130, $47.95) and MPLAB Code Configurator, which is a plug-in for Microchip’s freeMPLAB X IDE provides a graphical method to configure 8-bit systems and peripheral features, and gets you from concept to prototype in minutes by automatically generating efficient and easily modified C code for your application.

The PIC(L)F1764, PIC(L)F1765, PIC16(L)F1768, and PIC(L)F1769 are available now for sampling in 14- and 20-pins in PDIP, SOIC, SSOP, TSSOP, and QFN packages. Pricing for the family starts at $0.87 each, in 10,000-unit quantities.

Source: Microchip Technology

Fuzzy Logic for Embedded Microcontrollers

Fuzzy logic doesn’t necessarily need lots of horsepower. Many embedded applications that use more traditional control schemes can benefit from the use of fuzzy logic. Back in 1995, Jim Sibigtroth explained how to keep things simple and speedy.

In Circuit Cellar 56, Sibigtroth writes:

After describing basic fuzzy logic concepts, this article explains how to implement fuzzy-inference algorithms in a general-purpose embedded controller. The examples, written in assembly language, are for an MC68HC11, but the algorithms could be adapted for any general-purpose microcontroller. Code size is surprisingly small and execution time is fast enough to make fuzzy logic practical even in small embedded applications.

Perhaps because of its strange sounding name, fuzzy logic is still having trouble getting accepted as a serious engineering tool in the United States. In Japan and Europe, the story is quite different. The Japanese culture seems to respect ambiguity, so it is considered an honor to have a product which includes fuzzy logic. Japanese consumers understand fuzzy logic as intelligence similar to that used in human decisions.

In the US, engineers typically take the position that any control methodology without precise mathematical models is unworthy of serious consideration. In light of all the fuzzy success stories, this position is getting hard to defend.

I think the European attitude is more appropriate. It recognizes fuzzy logic as a helpful tool and uses it. They regard the difficulties of the nomenclature as a separate problem. Since the term “fuzzy” has negative connotations, they simply don’t advertise that products include fuzzy logic.

Figure l--Traditional sets are simply defined by their endpoints. Fuzzy sets add a second dimension to express fhe degree of truth (on the y-axis), which allows sets to be defined with gradual boundaries between false and true.

Figure l: Traditional sets are simply defined by their endpoints. Fuzzy sets add a second dimension to express the degree of truth (on the y-axis), which allows sets to be defined with gradual boundaries between false and true.

Curiously, the results produced by fuzzy-logic systems are as precise and repeatable as those produced by respected traditional methods. Instead of indicating lack of precision, the term “fuzzy” more accurately refers to the way real-world sets have gradual boundaries.

When we say “the temperature is warm,” there is not a specific temperature at which this expression goes from completely false to completely true. Instead, there is a gradual or fuzzy boundary, which requires a nonbinary description of truth. In fact, the fuzzy logic definition for a set contains more information than the conventional binary definition of a set.

In conventional systems, the range of an input parameter is broken into sets that begin and end at specific values. For example, a temperature range described as warm might include the temperatures 56-84°F (see Figure la). The trouble with this thinking is that the temperature 84.01”F suddenly stops being considered warm. This abrupt change is not the way humans think of concepts like “temperature is warm.”

Read the entire article, which appeared in Circuit Cellar 56, 1995.

New Power MOSFET Drivers Feature Thermally Efficient, Small Packages

Microchip Technology recently announced the first power MOSFET drivers in a new product family—the MCP14A005X and MCP14A015X. The drivers feature a new driver architecture for high-speed operation.MicrochipMCP14

The new devices’ small packaging (SOT-23 and 2 mm × 2 mm DFN packages) enables higher power densities and smaller solutions, while the design targets fast transitions and short delay times that allow for responsive circuit operation. In addition, the MOSFET drivers include low input threshold voltages that are compatible with low-voltage microcontrollers (MCUs) and controllers, while still maintaining strong noise immunity and hysteresis.


The MCP14A005X and MCP14A015X MOSFET drivers low input threshold is compatible with various Microchip PIC microcontrollers and dsPIC Digital Signal Controllers (DSCs), even when operating at lower voltages. This enables you to design applications with MCUs operating as low as 2 V, using the MOSFET driver to boost the output signals to 18 V, reducing power loss in the controller and minimizing conduction loss in the power MOSFET. The threshold levels balance the need for noise immunity with the ability to function with a wider variety of controller products, including Microchip’s devices. These drivers are designed for use in power supply, lighting, automotive, and consumer electronics markets, including embedded power conversion, brushed DC motor, unipolar stepper motor and solenoid/relay/valve control applications, among others.


The MCP14A005X and MCP14A015X are available now for sampling and volume production in  SOT-23 and 2 × 2 mm DFN packages. Prices range from $0.50 to $0.61 each in 10,000-unit quantities.

Source: Microchip Technology 

µTrace Supports New LPC54100 Series Microcontrollers

Lauterbach has announced its support for the new NXP Semiconductors LPC54100 Series of microcontrollers. NXP recently introduced its LPC54100 series, which achieves industry leading power efficiency and is ideally suited for “always-on” sensor-based products.utrace nxp lpc54100 series microcontrollers

Lauterbach has supported the LPC54100 Series of microcontrollers since the beginning with µTrace, a proven and popular debug and trace tool for Cortex-M-based processors. The tool uses USB 3.0 for connection to the host and connects to the LPC54100 via Serial Wire Debug (SWD) interface. The developer can control the operation of the program and analyze the data in C and C++ by the use of simple and complex breakpoints. An analog probe can be connected to µTrace to read the current and voltage measurements for energy profiling, which enables developers to fine-tune their software for minimal power usage.

The LPC54100 Series features an asymmetric dual-core architecture to enable scalable active power and performance by using a Cortex-M0+ and a Cortex-M4F for different sensor-processing tasks to optimize power efficiency. µTrace fully supports this type of asymmetric multicore processing (AMP) debugging by starting an individual TRACE32 instance for each core.

Source: Lauterbach

Embedded Chip = Subdermal Chip?

Forget stashing your cash under your mattress. Now you can stash it under your skin. Sort of.

The Telegraph reported Tuesday that Martijn Wismeijer, a Dutch innovator, recently implanted a 12-mm xNTi NFC chip in his body to store Bitcoin. The small glass chip stores 888 bytes and comes with a syringe for installation.

According the Dangerous Things site, the kit includes:

  • Glass chip preloaded in EO gas sterilized injector
  • A skin antiseptic
  • Gauze pads, a bandage, and non-latex surgical gloves


Source: Telegraph

New Digitally Enhanced Power Analog Controllers

Microchip Technology recently announced its latest Digitally Enhanced Power Analog (DEPA) controllers—the MCP19118 and MCP19119—which offer analog PWM control for DC-DC synchronous buck converters up to 40 V with the configurability of a digital microcontroller. MicrochipMCP19118

Interestingly, the devices bring together 40-V operation and PMBus communication interfaces for power-conversion circuit development with an analog control loop that is programmable in the integrated 8-bit PIC core’s firmware.  According to Microchip in a product release, “this integration and flexibility is ideal for power-conversion applications, such as battery-charging, LED-driving, USB Power Delivery, point-of-load and automotive power supplies.”

As expected, Microchip’s MPLAB X, PICkit 3, PICkit serial analyzer, and MPLAB XC8s support the MCP19118/9 DEPA controllers. The MCP19118 and MCP19119 are now available with prices starting at $2.92 each in 5,000-unit quantities.


One Professor and Two Orderly Labs

Professor Wolfgang Matthes has taught microcontroller design, computer architecture, and electronics (both digital and analog) at the University of Applied Sciences in Dortmund, Germany, since 1992. He has developed peripheral subsystems for mainframe computers and conducted research related to special-purpose and universal computer architectures for the past 25 years.

When asked to share a description and images of his workspace with Circuit Cellar, he stressed that there are two labs to consider: the one at the University of Applied Sciences and Arts and the other in his home basement.

Here is what he had to say about the two labs and their equipment:

In both labs, rather conventional equipment is used. My regular duties are essentially concerned  with basic student education and hands-on training. Obviously, one does not need top-notch equipment for such comparatively humble purposes.

Student workplaces in the Dortmund lab are equipped for basic training in analog electronics.

Student workplaces in the Dortmund lab are equipped for basic training in analog electronics.

In adjacent rooms at the Dortmund lab, students pursue their own projects, working with soldering irons, screwdrivers, drills,  and other tools. Hence, these rooms are  occasionally called the blacksmith’s shop. Here two such workplaces are shown.

In adjacent rooms at the Dortmund lab, students pursue their own projects, working with soldering irons, screwdrivers, drills, and other tools. Hence, these rooms are occasionally called “the blacksmith’s shop.” Two such workstations are shown.

Oscilloscopes, function generators, multimeters, and power supplies are of an intermediate price range. I am fond of analog scopes, because they don’t lie. I wonder why neither well-established suppliers nor entrepreneurs see a business opportunity in offering quality analog scopes, something that could be likened to Rolex watches or Leica analog cameras.

The orderly lab at home is shown here.

The orderly lab in Matthes’s home is shown here.

Matthes prefers to build his  projects so that they are mechanically sturdy. So his lab is equipped appropriately.

Matthes prefers to build mechanically sturdy projects. So his lab is appropriately equipped.

Matthes, whose research interests include advanced computer architecture and embedded systems design, pursues a variety of projects in his workspace. He describes some of what goes on in his lab:

The projects comprise microcontroller hardware and software, analog and digital circuitry, and personal computers.

Personal computer projects are concerned with embedded systems, hardware add-ons, interfaces, and equipment for troubleshooting. For writing software, I prefer PowerBASIC. Those compilers generate executables, which run efficiently and show a small footprint. Besides, they allow for directly accessing the Windows API and switching to Assembler coding, if necessary.

Microcontroller software is done in Assembler and, if required, in C or BASIC (BASCOM). As the programming language of the toughest of the tough, Assembler comes second after wire [i.e., the soldering iron].

My research interests are directed at computer architecture, instruction sets, hardware, and interfaces between hardware and software. To pursue appropriate projects, programming at the machine level is mandatory. In student education, introductory courses begin with the basics of computer architecture and machine-level programming. However, Assembler programming is only taught at a level that is deemed necessary to understand the inner workings of the machine and to write small time-critical routines. The more sophisticated application programming is usually done in C.

Real work is shown here at the digital analog computer—bring-up and debugging of the master controller board. Each of the six microcontrollers is connected to a general-purpose human-interface module.

A digital analog computer in Matthes’s home lab works on master controller board bring-up and debugging. Each of the six microcontrollers is connected to a general-purpose human-interface module.

Additional photos of Matthes’s workspace and his embedded electronics and micrcontroller projects are available at his new website.




New 40-nm Microcontrollers for Motor Control

Renesas Electronics Corp. recently announced the RH850/C1x series of 32-bit microcontrollers (MCUs), which it said are designed for motor control in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Based on Renesas’s 40-nm process, the RH850/C1x series features the RH850/C1H and RH850/C1M MCUs, which enable embedded designers to enhance efficiency, reduce system costs, and achieve higher safety levels for HEV/EV motor control systems.

Source: Renesas Electronics Corp.

Source: Renesas Electronics Corp.

The new RH850/C1x devices can be used with the RAA270000KFT RH850 family power supply management IC (PMIC), which is currently available in sample quantities. The power management IC integrates into one device all the power supply systems required for MCU operation, two external sensor power supply tracks, and a full complement of monitoring and diagnostic functions, significantly reducing the user burden associated with power supply system design.

The RH850/C1H and RH850/C1M MCUs incorporate large memory capacities achieved through 40 nm MONOS process technology. The RH850/C1x series is based on Renesas’s metal oxide nitride oxide silicon (MONOS) embedded flash, which has an extensive track record in mass production. The MONOS characteristics include fast readout, low power consumption, and large storage capacity. The RH850/C1M and RH850/C1H devices offer memory capacities of 2 MB and 4 MB, respectively. In addition, 32-KB data flash memory, with essentially the same functionality as EEPROM, is included for data storage.

The microcontrollers also feature an extensive set of peripheral functions for HEV/EV motor control. The RH850/C1x MCUs can implement three types of motor control in hardware: sine wave PWM, over modulation, and square wave.

Samples of the RH850/C1H and RH850/C1M MCUs are scheduled to be available from the beginning of 2015 and will cost $45 and $50 per unit, respectively. Mass production is scheduled for May 2016 and is expected to reach a scale of 100,000 units per month.

Source: Renesas Electronics Corp.

DIY Arduino-Based ECG System

Cornell University students Sean Hubber and Crystal Lu built an Arduino-based electrocardiography (ECG) system that enables them to view a heart’s waveform on a mini TV. The basic idea is straightforward: an Arduino Due converts a heartbeat waveform to an NTSC signal.

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s time base. (Source: Hubber & Lu)

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s
time base. (Source: Hubber & Lu)

In their article, “Hands-On Electrocardiography,” Hubber and Lu write:

We used the Arduino Due to convert the heartbeat waveform to an NTSC signal that could be used by a mini-TV. The Arduino Due continuously sampled the input provided by the voltage limiter at 240 sps. Similar to MATLAB, the vectorized signal was shifted left to make room at the end for the most recent sample. This provided a continuous real-time display of the incoming signal. Each frame outputted to the mini-TV contains two waveforms. One has a 1-s screen width and the other has a 5-s screen width. This enables the user to see a standard version (5 s) and a more zoomed in version (1 s). Each frame also contains an integer representing the program’s elapsed time. This code was produced by Cornell University professor Bruce Land.

As you can see in the nearby block diagram, Hubber and Lu’s ECG system comprises a circuit, an Arduino board, a TV display, MATLAB programming language, and a voltage limiter.

The system's block diagram (Circuit Cellar 289, 2014)

The system’s block diagram (Circuit Cellar 289, 2014)

The system’s main circuit is “separated into several stages to ensure that retrieving the signal would be user-safe and that sufficient amplification could be made to produce a readable ECG signal,” Hubber and Lu noted.

The first stage is the conditioning stage, which ensures user safety through DC isolation by initially connecting the dry electrode signals directly to capacitors and resistors. The capacitors help with DC isolation and provide a DC offset correction while the resistors limit the current passing through. This input-conditioning stage is followed by amplification and filtering that yields an output with a high signal-to-noise ratio (SNR). After the circuit block, the signal is used by MATLAB and voltage limiter blocks. Directly after DC isolation, the signal is sent into a Texas Instruments INA116 differential amplifier and, with a 1-kΩ RG value, an initial gain of 51 is obtained. The INA116 has a low bias current, which permits the high-impedance signal source. The differential amplifier also utilizes a feedback loop, which prevents it from saturating.

Following the differentiation stage, the signal is passed through multiple filters and receives additional amplification. The first is a low-pass filter with an approximately 16-Hz cutoff frequency. This filter is primarily used to eliminate 60-Hz noise. The second filter is a high-pass filter with an approximately 0.5-Hz cutoff frequency. This filter is mostly used to eliminate DC offset. The total amplification at this stage is 10. Since the noise was significantly reduced and the SNR was large, this amplification produced a very strong and clear signal. With these stages done, the signal was then strong enough to be digitally analyzed. The signal could then travel to both the MATLAB and voltage limiter blocks.

Hubber and Lu’s article was published in Circuit Cellar 289, 2014. Get it now!

New DSP “Lab-in-a-Box” for ARM-Based Audio Systems

Cambridge, UK-based, ARM and its partners will start shipping a DSP “Lab-in-a-Box” (LiB) to universities worldwide to help boost practical skills development and the creation of new ARM-based audio systems. This will include products such as high-definition home media and voice-controlled home automation systems. The LiB kits contain ARM Cortex-M4-based microcontroller boards by STMicroelectronics and audio cards from Wolfson Microelectronics and Farnell element14.ARMDSPLiBWeb

As the centerpiece of the ARM University Program, LiB packages offer ARM-based technology and high-quality teaching and training materials that support electronics and computer engineering courses. DSP courses have traditionally used software simulation packages, or hands-on labs using relatively expensive development kits costing around $300 per student. By comparison, this new DSP LiB will cost around $50 and will allow students to practice theory with advanced hardware sourced from widely-available products.

“Our Lab-in-a-Box offerings are proving hugely popular in universities because of the low-cost access to state-of-the-art technology,” said Khaled Benkrid, manager of the Worldwide University Program, ARM. “The DSP kits, powered by ARM Cortex-M4-based processors, enable high performance yet energy-efficient digital signal processing at a very affordable price. We expect to see them being used by students to create commercially-viable audio applications and it’s another great example of our partnership supporting engineers in training and beyond.”

The DSP LiB will begin shipping to universities in July 2014. It is the latest in a series of initiatives led by ARM which span multiple academic topics including embedded systems design, programming and SoC design. The DSP kits will also be offered to developers outside academia at a later date.


Specs & Code Matter (EE Tip #136)

No matter how many engineering hours you’ve logged over the years, it’s always a good idea to keep in mind that properly focusing on specs and code can make or break a project. In 2013, Aubrey Kagan—an experienced engineer and long-time Circuit Cellar author—explained this quite well in CC25:

There was a set of BCD thumbwheel switches that I was reading into a micro. In order to reduce the number of input lines required, each 4 bits of a digit was multiplexed with the other digits and selection was made by a transistor enabling the common line of each switch in turn. This was standard industry practice. The problem was that in order to economize, I had used the spare transistors in a Darlington driver IC. Everything worked fine in the lab, but on very hot days the unit would fail in the field with very strange results.

Long story short, the saturation voltage on the Darlington transistor would increase with temperature to above the digital input threshold and the micro would read undefined switch settings and then jump to non-existing code. I learned three things: read and understand all the specifications on a datasheet, things get a lot hotter in a cabinet in the sun than the lab, and you should make sure your code can handle conditions that are not supposed to occur.—Aubrey Kagan, CC25 (2o13)

Want to share an EE tip of your own? Email our editors to share your tips and tricks.

July Issue Offers Data-Gathering Designs and More

The concept of the wireless body-area network (WBAN), a network of wireless wearable computing devices, holds great promise in health-care applications.

Such a network could integrate implanted or wearable sensors that provide continuous mobile health (mHealth) monitoring of a person’s most important “vitals”—from calorie intake to step count, insulin to oxygen levels, and heart rate to blood pressure. It could also provide real-time updates to medical records through the Internet and alert rescue or health-care workers to emergencies such as heart failures or seizures.

Data Gathering DesignsConceivably, the WBAN would need some sort of controller, a wearable computational “hub” that would track the data being collected by all the sensors, limit and authorize access to that information, and securely transmit it to other devices or medical providers.

Circuit Cellar’s July issue (now available online for membership download or single-issue purchase)  features an essay by Clemson University researcher Vivian Genaro Motti, who discusses her participation in the federally funded Amulet project.

Amulet’s Clemson and Dartmouth College research team is prototyping pieces of “computational jewelry” that can serve as a body-area network’s mHealth hub while being discreetly worn as a bracelet or pendant. Motti’s essay elaborates on Amulet’s hardware and software architecture.

Motti isn’t the only one aware of the keen interest in WBANs and mHealth. In an interview in the July issue, Shiyan Hu, a professor whose expertise includes very-large-scale integration (VLSI), says that many of his students are exploring “portable or wearable electronics targeting health-care applications.”

This bracelet-style Amulet developer prototype has an easily accessible board.

This bracelet-style Amulet developer prototype has an easily accessible board.

Today’s mHealth market is evident in the variety of health and fitness apps available for your smartphone. But the most sophisticated mHealth technologies are not yet accessible to embedded electronics enthusiasts. (However, Amulet has created a developer prototype with an easily accessible board for tests.)

But market demand tends to increase access to new technologies. A BCC Research report predicts the mHealth market, which hit $1.5 billion in 2012, will increase to $21.5 billion by 2018. Evolving smartphones, better wireless coverage, and demands for remote patient monitoring are fueling the growth. So you can anticipate more designers and developers will be exploring this area of wearable electronics.

In addition to giving you a glimpse of technology on the horizon, the July issue provides our staple of interesting projects and DIY tips you can adapt at your own workbench. For example, this issue includes articles about microcontroller-based strobe photography; a thermal monitoring system using ANT+ wireless technology; a home solar-power setup; and reconfiguring and serial backpacking to enhance LCD user interfaces.

We’re also improving on an “old” idea. Some readers may recall contributor Tom Struzik’s 2010 article about his design for a Bluetooth audio adapter for his car (“Wireless Data Exchange: Build a 2,700-lb. Bluetooth Headset,” Circuit Cellar 240).

In the July issue, Struzik writes about how he solved one problem with his design: how to implement a power supply to keep the phone and the Bluetooth adapter charged.

“To run both, I needed a clean, quiet, 5-V USB-compatible power supply,” Struzik says. “It needed to be capable of providing almost 2 A of peak current, most of which would be used for the smartphone. In addition, having an in-car, high-current USB power supply would be good for charging other devices (e.g., an iPhone or iPad).”

Struzik’s July article describes how he built a 5-V/2-A automotive isolated switching power supply. The first step was using a SPICE program to model the power supply before constructing and testing an actual circuit. Struzik provides something extra with his article: a video tutorial explaining how to use Linear Technology’s LTspice simulator program for switching design. It may help you design your own circuit.

This is Tom Struzik's initial test circuit board, post hacking. A Zener diode is shown in the upper right, a multi-turn trimmer for feedback resistor is in the center, a snubber capacitor and “stacked” surface-mount design (SMD) resistors are on the center left, USB D+/D– voltage adjust trimmers are on top center, and a “test point” is shown in the far lower left. If you’re looking for the 5-V low dropout (LDO) regulator, it’s on the underside of the board in this design.

This is Tom Struzik’s initial test circuit board, post hacking. A Zener diode is shown in the upper right, a multi-turn trimmer for feedback resistor is in the center, a snubber capacitor and “stacked” surface-mount design (SMD) resistors are on the center left, USB D+/D– voltage adjust trimmers are on top center, and a “test point” is shown in the far lower left. If you’re looking for the 5-V low dropout (LDO) regulator, it’s on the underside of the board in this design.