Are Today’s MCUs Overdesigned? A Research Team Has The Answer

MCUs are called microcontrollers because they embed a CPU, memory and I/O units in one package. Apparently, today’s MCUs are full of peripherals and in most cases they are not used in the application, and from an engineering point of view this is a waste of money and energy, but on the other hand, for developers and consumers it’s about programmability and flexibility.

Rakesh Kumar a University of Illinois electrical and computer engineering professor and John Sartori a University of Minnesota assistant professor tried to prove that processors are overdesigned for most applications.

Kumar and his colleagues did 15 ordinary MCU applications using openMSP430 microcontroller with bare metal and RTOS approach (both are tested in their study). Surprisingly, the results showed that all of these applications needed no more than 60 percent of the gates. Therefore, smaller MCUs can be used (cheaper and less power consuming). As stated by Sartori, “a lot of logic that can be completely eliminated, and the software still works perfectly”.

Bespoke Processor research results
Image courtesy by: University of Illinois/ACM

In the image above the analysis of unused gates for two applications: Interpolation FIR filter and Scrambled Interpolation FIR. The red dots are the used gates and gray ones are the not used ones.

The research team called the optimum MCU the “Bespoke Processor”, and described the process “like a black box. Input the app, and it outputs the processor design.” says Kumar.

Source: IEEE Spectrum

Banana Pi BPI-M2 Berry, A Quad Core Single-Board Computer

Raspberry Pi is a powerful on-board computer series launched few years ago. Many similar boards appeared providing cheaper price or more features. The Chinese company “SinoVoIP” is manufacturing its own board “Banana Pi“, and recently they unveiled a new board that is similar to Raspberry Pi 3 and called “BPI-M2 Berry“.

The BPi Berry features the Allwinner R40 32-bit quad-core ARM Cortex-A7 CPU giving it the same power of Raspberry Pi 2 version 1.0. It is similar to the BPi M2 Ultra that was released a few months back, but with 1 GB DDR3 SRAM instead of 2 GB and without eMMC Flash Memory. BPi Berry has a different size of other BPi boards, making it the first RPi size-compatible BPi with the same size and connector placement as the RPi3.

Banana Pi BPI-M2 Berry specifications:

  • SoC – Allwinner V40 quad Core ARM Cortex A7 processor with ARM Mali-400MP2 GPU
  • System Memory – 1G DDR3 SDRAM
  • Storage – micro SD slot, SATA interface
  • Connectivity – 1x Gigabit Ethernet port, 802.11 b/g/n WiFi and Bluetooth 4.0 (AP6212 module)
  • Video Output – HDMI 1.4 port up to 1080p60, 4-lane MIPI DSI display connector
  • Audio I/O – HDMI, 3.5mm headphone jack, built-in microphone
  • USB – 4x USB 2.0 host ports, 1x micro USB OTG port
  • Camera – CSI camera connector
  • Expansion – 40-pin Raspberry Pi compatible header with GPIOs, I2C, SPI, UART, ID EEPROM, 5V, 3.3V, GND signals.
  • Debugging – 3-pin UART for serial console
  • Misc – Reset, power, and u-boot buttons
  • Power Supply – 5V via micro USB port; AXP221s PMIC
  • Dimensions – 85mm x 56mm

Compared with RPi3, BPi Berry adds a SATA port that allows the connection of an external hard disk or DVD/CDROM drive, which is convenient for applications that require lots of storage or faster throughput compared to USB memory sticks. Also there are differences in camera and display connectors, they are in the same place but with different sizes and the SD card slot is wider too.

BPi M2 Berry is available for about $45. For more details about the board visit the official announcement and take a look at this review on elektor.

How to Route Differential Pairs

Sam Sattel @ autodesk.com discuss about the benefits of differential signals and how to route them in Eagle.

If you’re designing a high speed PCB, then chances are you’re working with the latest and most powerful technologies, like HDMI, USB3.0, Ethernet, or DDR. But with great power comes great responsibility! As a result, you’ll likely be dealing with issues like electromagnetic interference (EMI) and noise.

So what do you do about these problems? When you’ve got a bunch of noisy signals on your board and you need a way to protect the transmission of your data then you need to be using differential pairs. In this blog we’ll be looking at all of the great benefits for using differential pairs in your high speed design project, and how to route them in Autodesk EAGLE.

How to Route Differential Pairs – [Link]

Solr: Digital Wrist Watch Calculates time from Sun Position

Time can be calculated using the azimuth of the sun (aka solar time). Based on this idea, Tinkerman has built an unusual project called Solr. The concept is to translate the position of the sun into time presented on a vintage display. This new digital watch is freak enough to work only with a battery and the sun. The battery is needed to power the electronic parts and the sun is needed to calibrate the shadow of a screw with a reference line to calculate the time digitally using a digital compass.

Solr watch in action

The PCB has a white line and all you have to do is to align the shadow of the screw to it. The science behind this project rely on the fact that a change of 1 degree in longitude equals to 4 minutes. So, as the day is passing the orientation you need to follow to make the shadow align with the white line increases and therefore the time can be calculated. HMC5883L ( 3-axis digital magnetometer) is used to determine the orientation. This chunk of code in Solr’s repo makes the method used to calculate the time very clear.

The firmware (written in Arduino C) behind this project has three main tasks:

  1. Calibrating the HMC5883L, and the calibration procedure is explained in the HMC5883L datasheet.
  2. Calculate the time according to the bearing of the circuit.
  3. Display on HP QDSP-6064 display.

HP QDSP-6064 display

The PCB is assembled using the assembling service (PCBA) from Seeedstudio and designed using Eagle CAD. You can download the source files from here.

 

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XBEE X V2 FPV Racing Drone Kit

XBEE, the FPV racing drones manufacturer, had produced recently its new racing frame “XBEE X V2” for $75. It is a follow-up to the previous model “The XB-X Mk2” and it is a quad drone frame with a camera on its body. X V2 is designed with Wheelbase 220mm size guide.

First-person view (FPV) is also known as video piloting. Using this technique you can control a radio-controlled vehicle from the driver or pilot’s view point. The vehicle is either driven or piloted remotely from a first-person perspective via an onboard camera, fed wirelessly to video FPV goggles or a video monitor.

V2 Features:

  • Full Carbon Fiber.
  • 2mm Bottom Plate, 2mm Top Plate and 4mm arms
  • Matek PDB include(PDB-XPW W/ CURRENT SENSOR 140A & DUAL BEC)
  • Black steel screws(option titanium screws)
  • Transmitter mount include
  • weight : 79g

To build a full drone with the V2 frame you will need these parts with a total budget of about $450:

This video by X-FramesFPV will show you how to build XBEE X V2:

You can also follow this guide for detailed instructions of a full build of V2.

YouTube channel IoT view counter

Kenneth Finnegan built this YouTube channel IoT view counter. He writes:

I’ve wanted an Internet connected read-out for some time now, inspired by the awesome shadow box IoT projects Becky Stern has been doing (weather, YouTube subscribers). I’m certainly not to the same level of packaging as her yet, but I’ve got a functional display working with a Hazzah and an eBay seven segment display module.

YouTube channel IoT view counter – [Link]

20V, 4 MHz, synchronous 2x 6A step-down regulator in 20 sq mm

Graham Prophet @ eedesignnewseurope.com presents the LTC3636 and LTC3636-1 synchronous step-down regulator from Linear:
LTC3636 and LTC3636-1 are high efficiency, 4 MHz synchronous dual output buck regulators that incorporate a constant frequency/controlled on-time, current mode control scheme with phase lockable switching frequency. Their design architecture reduces conducted and radiated emissions.
20V, 4 MHz, synchronous 2x 6A step-down regulator in 20 sq mm – [Link]

Mokacam Alpha, The World’s Smallest 4K Camera

Have you ever imagined to record your life at high quality with a small and an affordable camera? Mokacam, the camera producer company is making this possible. After the success of the first version, Mokacam had launched its new 4K camera, Alpha. Initially, Alpha is a smaller and more powerful version featuring Ambarella processor for 4K video to 120 FPS super slow motion. In addition, Alpha weighs only 79g and is sized 45x45mm.

Alpha is attachable to a shutter wheel to enable you shoot long exposure night photos. In Manual mode, you can turn the shutter wheel to set the shutter speed freely from 1/2000″ up to 32″. Additionally, you will forget completely the need of charging it again. Thanks to the built-in-battery feature, you can expect 4 hours continuous 1080P@30FPS video recording. Otherwise, you can add snap-on batteries and record forever!

Mokacam Alpha captures brighter image with more details under low light environment. The Ambrella image processor and the 1.55μm Sony image sensor provides features of 4K Ultra-HD or Full-HD 1/5 Speed Slow Motion video with incredible image quality.

Mokacam Alpha Features

Check this video to know the full features of Mokacam Alpha.

In this video you can find Mokacam Alpha compared to GoPro Hero 5 Black. Also, you can find below its competitive advantages.

Amazingly, Alpha was live on a crowdfunding campaign on Indigogo and it reached 1200% of its goal! You can check the official website and the product page for more details. Finally, you can pre-order Alpha now for $215 as a limited edition.

Keysight Technologies’ E36300 series bench power supplies

Martin Rowe @ edn.com presents the new Keysight E36300 bench power supply with triple output and some great features.

Keysight Technologies’ E36300 series of bench power supplies provide three outputs with power of 80 W or 160 W with line/load regulation of 0.01%. Front-panel buttons let you turn any output on or off and you can configure each output with 2-wire local sensing or 4-wire remote sensing. The 4-wire sensing removes losses caused by IR drops in your power-delivery wires.

Keysight Technologies’ E36300 series bench power supplies – [Link]

Tri-axis sensor embeds pedometer

Susan Nordyk @ edn.com discuss about the Kionix’s accelerometer with integrated pedometer.

The K126 16-bit tri-axis digital accelerometer from Kionix integrates a step detector and step counter, yet minimizes power consumption. Housed in a tiny 2×2×0.9-mm LGA package, the K126 offers user-selectable g ranges of ±2 g, ±4 g, and ±8 g and output data rates of up to 25.6 kHz.

Tri-axis sensor embeds pedometer – [Link]