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Top 10 Popular Microcontrollers Among Makers

Posted on 19 June, 20204 August, 2020 by Emmanuel Odunlade

At the heart of any embedded electronics device, either on a DIY or professional product level is a microcontroller. They run the codes/firmware that helps developers obtain inputs from sensors and tie it to actions executed through actuators. While they are usually developed as general-purpose components, MCUs are built with certain features and functionalities that make them suitable and (or) preferred by certain developers for certain applications, use cases, or scenarios. These features and functionalities have increased to meet current technological demands, making the microcontrollers not just more powerful, but more diverse, creating a selection headache for designers. Today’s article will, in no particular order, highlight the 10 most popular microcontrollers based on how often they have featured in products and the size of the communities around them.

Ready? let’s go

1. STM32F103C8T6

The STM32F10C8T6 is a popular member of the STM32F103xx medium-density performance line family of microcontrollers that feature a high-performance ARM® Cortex®-M3 32-bit RISC core operating at a 72 MHz frequency and possess an extensive range of enhanced I/Os and peripherals connected to two APB buses. All members of the STM32F103x family, including the CT86, offer two 12-bit ADCs, three general-purpose 16-bit timers plus one PWM timer, as well as standard and advanced communication interfaces: up to two I2Cs and SPIs, three USARTs, an USB and a CAN.

Features:

ARM® 32-bit Cortex®-M3 CPU Core – 72 MHz maximum frequency, 1.25 DMIPS/MHz (Dhrystone 2.1) performance at 0 wait state memory access – Single-cycle multiplication and hardware division
Memories
- 64 or 128 Kbytes of Flash memory
- 20 Kbytes of SRAM
Clock, reset and supply management
- 2.0 to 3.6 V application supply and I/Os
- POR, PDR, and programmable voltage detector (PVD)
- 4-to-16 MHz crystal oscillator
- Internal 8 MHz factory-trimmed RC
- Internal 40 kHz RC – PLL for CPU clock
- 32 kHz oscillator for RTC with calibration
Low-power Sleep, Stop and Standby modes
- VBAT supply for RTC and backup registers
- 2 x 12-bit, 1 µs A/D converters (up to 16 channels)
- Conversion range: 0 to 3.6 V
- Dual-sample and hold capability
- Temperature sensor
DMA
- 7-channel DMA controller
- Peripherals supported: timers, ADC, SPIs, I 2Cs and USARTs
Up to 80 fast I/O ports
- 26/37/51/80 I/Os, all mappable on 16 external interrupt vectors and almost all 5 V-tolerant
Debug mode – Serial wire debug (SWD) & JTAG interfaces
7 timers
- Three 16-bit timers, each with up to 4 IC/OC/PWM or pulse counter and quadrature (incremental) encoder input
- 16-bit, motor control PWM timer with deadtime generation and emergency stop
- 2 watchdog timers (Independent and Window)
- SysTick timer 24-bit down counter
Up to 9 communication interfaces – Up to 2 x I2C interfaces (SMBus/PMBus)
- Up to 3 USARTs (ISO 7816 interface, LIN, IrDA capability, modem control)
- Up to 2 SPIs (18 Mbit/s)
- CAN interface (2.0B Active)
- USB 2.0 full-speed interface

Development Boards based on MCU:

Blue Pill

2. ATmega328

Arguably one of the most popular microcontrollers in the world, the Atmega328p has been the microcontroller of choice to a lot of designers who want to avoid the bulkiness of the Arduino boards, but retain the ease of programming, community support, and other amazing features associated with the Arduino development platform. It’s an 8-bit AVR microcontroller based on an advanced RISC architecture and combines 32KB ISP flash memory with read-while-write capabilities.

Features:

1KB EEPROM, 2KB SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible timer/counters with compare modes, internal and external interrupts,serial programmable USART, a byte-oriented 2-wire serial interface, SPI serial port, 6-channel 10-bit A/D converter (8-channels in TQFP and QFN/MLF packages), and

Program Memory – 32KB (Flash)
CPU Speed (MIPS/DMIPS) – 20
1KB EEPROM
Digital Communication Peripherals – 1-UART, 2-SPI, 1-I2C
2KB SRAM
23 GPIO
6-channel 10-bit A/D converter (8-channels in TQFP and QFN/MLF packages)
5 software selectable power saving modes
3 builtin Timers with compare modes – 2 8bit and 1 16bit
PWM pins – 6
programmable watchdog timer with internal oscillator
32 general-purpose working registers,

Development Boards Based on MCU:

Arduino Nano
Arduino UNO
Arduino Pro Mini
Sparkfun Redboard
A host of other Arduino Clones

Standout Features:

Express Compatibility with the Arduino Development platform
Large community support due to relationship with Arduino

3. PIC16F877A

The PIC16F877A is arguably the most popular 8-bit microcontroller in the PIC family of MCUs. While it’s considered by some as old and past its time, the PIC16F877A is no doubt, still one of the most popular microcontrollers in the world. It is seen as the de-facto microcontroller for beginners looking to get into embedded development with PIC and it ends up as the microcontroller of choice for them when they become experts.

Features:

Some features of the PIC16F877A are provided below:

Total number of Pins – 40
Total number of ports – 5 (port A, port B, port C, port D, port E)
Operating Voltage – 2 to 5.5V
Number of input/output pins – 33
Number of ADC pins – 14
ADC Resolution – 10-bit
Number of Comparators – 2
Number of timers – 3
Communication protocols – UART, SPI, I2C
External Oscillator – up to 20Mhz
Program Memory – 14KB
RAM – 368 bytes
EEPROM – 256 bytes
Max PWM resolution – 10
Support both hardware pin and timer interrupts

Development Boards Based on MCU:

The PIC Development board

Dev boards are one of the reasons why PIC microcontrollers are increasingly becoming unpopular. While the PIC development boards are usually very good for beginners because they come with different components that aids learning, for the average designer, they are considered bulky and pretty much uninteresting to work with, as most of the components included are usually not needed by experienced designers.

4. Attiny85

Loved for their tiny form-factor, the ATtiny series of microcontrollers are considered as the go-to microcontroller for projects where a small form factor is desired, and the number of GPIOs required is low. Of all the microcontrollers in this series, the aTtiny85 is regarded as the most popular, presumably because it seems to have more I/O pins compared to others. While Microchip announced a new range of ATtiny chips with significant performance upgrades, the ATtiny85 is still revered, mostly because of the familiarity most designers have built with it over time.

Features:

Some features of the ATtiny85 include:

Total number of pins – 8
CPU type – RISC 8-Bit AVR
Operating Voltage – 1.8 – 5.5V
Program Memory – 8K
RAM Memory – 512Bytes
EEPROM Memory – 512Bytes
ADC Resolution – 10-Bit
Number of ADC pins – 4
Number of Comparators – 1
GPIO’s – 6
No of Timers – 2 8-bit timers
Communication Protocols- SPI, I2C, and USART.
Number of PWM pins – 4
Maximum oscillator speed – Up to 20MHz

Development Boards Based on MCU:

Mini ATtiny85 USB
Digispark ATtiny85

Standout Features:

Stand out feature for the ATtiny85 will be their small form-factor and their relatively low power consumption features.

5. MSP430G2452

The MSP430 family of microcontrollers from TI are considered as some of the most modern microcontrollers and the most popular member of that family so far has been the MSP430G2452. The MSP430G2452 is a powerful, and relatively cheap microcontroller based on a 16-bit RISC CPU manufactured by Texas Instruments.

Features:

Some features of the MCU include:

Number of Comparator channels – 8
ADC channels – 8
Number of GPIO’s pins – 16
ADC Resolution – 10-Bit SAR
Number of Timers – 1 (16-bit)
Non-Volatile Memory – 8kB
Communication protocols – 1 I2C, 1 SPI
Low Supply Voltage Range – 1.8V – 3.6V
Low-Frequency Oscillator-32-kHz Crystal and also external Digital Clock Source
SRAM – 256B
Active Mode Power consumption – 220microA at 1MHz

Development Boards Based on MCU:

MSP-EXP430G2 LaunchPad TI Development Board

Standout Features:

The MSP430 series of microcontrollers are famous for their low power features.

6. ESP8266

The popularity of the ESP8266 cannot be contested. It is unarguably one of the most impactful microcontrollers of the last decade and it definitely was one of the pacesetters for the current trend of microcontrollers with fused communication capabilities. Developed by Espressif Systems, the ESP8266 is a low-cost Wi-Fi microchip, with a full TCP/IP stack and microcontroller capability. Multiple versions of the MCU were created in quick succession and what started initially as a Wi-Fi module for microcontrollers quickly spurned off to a module like the ESP-12e which became the heart of several projects and products.

Features:

Processor: L106 32-bit RISC microprocessor core based on the Tensilica Xtensa Diamond Standard 106Micro running at 80 MHz
Memory:
- 32 KiB instruction RAM
- 32 KiB instruction cache RAM
- 80 KiB user-data RAM
- 16 KiB ETS system-data RAM
External QSPI flash: up to 16 MiB is supported (512 KiB to 4 MiB typically included)
IEEE 802.11 b/g/n Wi-Fi
- Integrated TR switch, balun, LNA, power amplifier and matching network
- WEP or WPA/WPA2 authentication, or open networks
16 GPIO pins
SPI
I²C (software implementation)
I²S interfaces with DMA (sharing pins with GPIO)
UART on dedicated pins, plus a transmit-only UART can be enabled on GPIO2
10-bit ADC (successive approximation ADC)

Development Boards Based on MCU:

There are over 100 development boards based on the different variations of the ESP8266. To mention a few, some of these boards include;

NodeMCU DevkIT
Wemos D1
Wemos D1 Mini
Adafruit Feather HUZZAH ESP8266
SparkFun ESP8266 Thing

Standout Features:

Some standout features of the ESP8266 includes;

Integrated WiFI and Microcontroller reduces BOM and sourcing related headaches
Low cost
pre-certified (FCC and CE)
large Community support
Compatibility with popular Platforms like the Arduino IDE

7. ESP32

An upgrade to the ESP8266, the esp32 has enjoyed great support and adoption since its release few years back. it is a low-cost, low-power system on a chip microcontroller with integrated Wi-Fi and dual-mode Bluetooth. it uses the Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations and includes built-in antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules. Designed for modern applications, ESP32 also incorporates several security features like Cryptographic hardware acceleration, flash encryption, and secure boot.

Features:

Some features of the MCU include:

Processors:
- CPU: Xtensa dual-core (or single-core) 32-bit LX6 microprocessor, operating at 160 or 240 MHz and performing at up to 600 DMIPS
- Ultra-low power (ULP) co-processor
Memory: 520 KiB SRAM
Wireless connectivity:
- Wi-Fi: 802.11 b/g/n
- Bluetooth: v4.2 BR/EDR and BLE (shares the radio with Wi-Fi)
Peripheral interfaces:
- 12-bit SAR ADC up to 18 channels
- 2 × 8-bit DACs
- 10 × touch sensors (capacitive sensing GPIOs)
- 4 × SPI
- 2 × I²S interfaces
- 2 × I²C interfaces
- 3 × UART
- SD/SDIO/CE-ATA/MMC/eMMC host controller
- SDIO/SPI slave controller
- Ethernet MAC interface with dedicated DMA and IEEE 1588 Precision Time Protocol support
- CAN bus 2.0
- Infrared remote controller (TX/RX, up to 8 channels)
- Motor PWM
- LED PWM (up to 16 channels)
- Hall effect sensor
- Ultra-low-power analog pre-amplifier
Security:
- IEEE 802.11 standard security features all supported, including WFA, WPA/WPA2 and WAPI
- Secure boot
- Flash encryption
- 1024-bit OTP, up to 768-bit for customers
- Cryptographic hardware acceleration: AES, SHA-2, RSA, elliptic curve cryptography (ECC), random number generator (RNG)
Power management:
- Internal low-dropout regulator
- Individual power domain for RTC
- 5μA deep sleep current
- Wake up from GPIO interrupt, timer, ADC measurements, capacitive touch sensor interrupt

Development Boards Based on MCU:

Like the ESP8266 there are a lot of development boards based on the ESP32. Some of these boards include;

HUZZAH32
ESP32-DevKitC
NodeMCU-32S
ESPduino32
ESP32 Thing

Standout Features:

Asides WiFi, ESP32 features Bluetooth and implements security and low power features that are not available in regular devices.

8. ATMEGA32U4

The Atmega32u4 is a low-power Microchip 8-bit AVR® RISC-based microcontroller featuring 32 KB self-programming flash program memory, 2.5 KB SRAM, 1 KB EEPROM, USB 2.0 full-speed/low-speed device, 12-channel 10-bit A/D-converter, and JTAG interface for on-chip-debug. The device is able to execute powerful instructions in a single clock cycle, enabling it to achieve up to 16 MIPS throughput at 16 MHz. This gives designers the ability to optimize power consumption versus processing speed.

Features:

Complies fully with Universal Serial Bus Specification Rev. 2.0
Supports data transfer rates up to 12 Mbit/s and 1.5 Mbit/s
Endpoint 0 for Control Transfers: Up to 64 bytes
Six Programmable Endpoints with In or Out Directions and with Bulk, Interrupt or Isochronous Transfers
Configurable Endpoints size up to 256 bytes in double bank mode
Fully independent 832 bytes USB DPRAM for endpoint memory allocation
Suspend/Resume Interrupts
CPU Reset possible on USB Bus Reset detection
48 MHz from PLL for Full-Speed Bus Operation
USB Bus Connection/Disconnection on Microcontroller Request
A crystal-less operation for Low-Speed mode

Development Boards Based on MCU:

The Atmega32u4 is a popular microcontroller and is featured in several development boards some which include;

Teensy 2.0
Arduino Beetle
Arduino Pro Micro
Arduino Leonardo
Qwicc Pro
Arduino Leonardo Clones

9. STM8S103F3

The STM8 family of microcontrollers offers a high-performance 8-bit core and a state-of-the-art set of peripherals in a tiny form factor, similar to what is obtainable with the ATtiny series of MCUs. The family is made up of 4 series including; the STM8S, the STM8L, the STM8AF, and the STM8AL. Of all these, the STM8S series is considered to be the mainstream MCU and the STM8S103F3 is considered to be one of the most popular MCUs in the Series.

The 8-bit microcontroller offers 8 Kbyte Flash program memory, with an integrated true data EEPROM, advanced core and peripherals, a 16 MHz clock frequency, robust I/Os, independent watchdogs with separate clock source, and a clock security system, all of which ensures its high performance and overall system robustness.

Features:

Highlight features of the microcontroller, according to the datasheet include:

Core
- 16 MHz advanced STM8 core with Harvard architecture and 3-stage pipeline
- Extended instruction set
Memories
- Program memory: 8 Kbyte Flash; data retention 20 years at 55 °C after 10 kcycle
- Data memory: 640 byte true data EEPROM; endurance 300 kcycle
- RAM: 1 Kbyte
Clock, reset and supply management
- 2.95 to 5.5 V operating voltage
- Flexible clock control, 4 master clock sources
  - Low power crystal resonator oscillator
  - External clock input
  - Internal, user-trimmable 16 MHz RC
  - Internal low-power 128 kHz RC
- Clock security system with clock monitor
- Power management:
  - Low-power modes (wait, active-halt, halt)
  - Switch-off peripheral clocks individually
- Permanently active, low-consumption power-on and power-down reset
Interrupt management
- Nested interrupt controller with 32 interrupts
- Up to 27 external interrupts on 6 vectors
Timers
- Advanced control timer: 16-bit, 4 CAPCOM channels, 3 complementary outputs, dead-time insertion and flexible synchronization
- 16-bit general purpose timer, with 3 CAPCOM channels (IC, OC or PWM)
- 8-bit basic timer with 8-bit prescaler
- Auto wake-up timer
- Window watchdog and independent watchdog timers
Communication interfaces
- UART with clock output for synchronous operation, SmartCard, IrDA, LIN master mode
- SPI interface up to 8 Mbit/s
- I2C interface up to 400 kbit/s
Analog to digital converter (ADC)
- 10-bit, ±1 LSB ADC with up to 5 multiplexed channels, scan mode and analog watchdog
I/Os
- Up to 28 I/Os on a 32-pin package including 21 high sink outputs
- Highly robust I/O design, immune against current injection
Unique ID
- 96-bit unique key for each device

Development boards Based on Microcontroller:

There are a lot of breakout boards based on the STM8S103F3 microcontroller that are not sophisticated enough to be classified as a development board. Some noteworthy boards based on the MCU include;

Sduino / STM8Blue and similar clones
STM8S103F3 P6 Development Board

10. NXP LPC1768

The LPC1768 is a Cortex®-M3 microcontroller designed for embedded applications with low power requirements. It features a high level of integration and low power consumption at frequencies of up to 100 MHz. It’s is a high-performance microcontroller and features up to 512 kB of flash memory and 64 kB of data memory, along with peripherals like an Ethernet MAC, a USB Device/Host/OTG interface, 8-channel DMA controller and 4 UARTs, among others.

Features

Some highlight features of the NXP LPC1768 includes:

Arm^® Cortex-M3 processor, running at frequencies of up to 100 MHz
Arm Cortex-M3 built-in Nested Vectored Interrupt Controller (NVIC)
Up to 512 kB on-chip flash programming memory
Up to 64 kB On-chip SRAM
In-System Programming (ISP) and In-Application Programming (IAP)
Eight channel General Purpose DMA controller (GPDMA)
Ethernet MAC with RMII interface and dedicated DMA controller
USB 2.0 full-speed device/Host/OTG controller
Four UARTs with fractional baud rate generation, internal FIFO, and DMA support
CAN 2.0B controller with two channels
SPI controller with synchronous, serial, full duplex communication
Two SSP controllers with FIFO and multi-protocol capabilities
Three enhanced I2C bus interfaces
I2S (Inter-IC Sound) interface
70 General Purpose I/O (GPIO) pins with configurable pull-up/down resistors
12-bit/8-ch Analog/Digital Converter (ADC) with conversion rates up to 200 kHz
10-bit Digital/Analog Converter (DAC) with dedicated conversion timer and DMA
Four general purpose timers/counters
One motor control PWM with support for three-phase motor control
Quadrature encoder interface that can monitor one external quadrature encoder
One standard PWM/timer block with external count input
Low power RTC with a separate power domain and dedicated oscillator
WatchDog Timer (WDT)
Arm Cortex-M3 system tick timer, including an external clock input option
Repetitive interrupt timer provides programmable and repeating timed interrupts
Each peripheral has its own clock divider for further power savings
Standard JTAG test/debug interface for compatibility with existing tools
Integrated PMU (Power Management Unit)
Four reduced power modes: Sleep, Deep-sleep, Power-down, and Deep power-down
Single 3.3 V power supply (2.4 V to 3.6 V)
Four external interrupt inputs configurable as edge/level sensitive
Non-maskable Interrupt (NMI) input
Wake-up Interrupt Controller (WIC)
Processor wake-up from Power-down mode via any interrupt
Brownout detect with separate threshold for interrupt and forced reset
Power-On Reset (POR)
Crystal oscillator with an operating range of 1 MHz to 25 MHz
4 MHz internal RC oscillator trimmed to 1 % accuracy
Code Read Protection (CRP) with different security levels
Unique device serial number for identification purposes

Development Boards:

Top development boards based on the NXP LPC1768 include;

With 1000s of microcontrollers in existence, there are definitely a few other microcontrollers out there that probably deserve a spot on this list, but you will agree with me that the community, projects, and products that have been built around the MCUs featured in these articles are hard to match.

What are your thoughts? what other microcontrollers do you think should have made this list? Feel free to share via the comment section.

Gameduino 3x Dazzler is an Arduino shield with a GPU, FPGA and an HDMI Port onboard.

Posted on 19 June, 2020 by Emmanuel Odunlade

Following the general success of the first version of the Gameduino, an Arduino Shield which allowed users to connect devices like VGA monitors and speakers to the Arduino, to create high-quality sprite/tile-based video games, James Bowman‘s excamera released improved versions of the device with built-in screens and graphics processors which were widely accepted within the open-source gaming communities. Spurred by these successes and the desire to provide users with a shield that reflects current technology realities, excamera recently announced the launch of a new version of the shield; the Gameduino 3x Dazzler.

A totally open-source, and hackable audiovisual platform, the Dazzler shield comprises of a BT815 GPU, a Xilinx Spartan-6 FPGA, an HDMI port, and two Wii Classic ports that give users the experience of a plug-and-play game console.

The combination of the BT815 GPU and the Xilinx Spartan-6 FPGA provided all that was needed to achieve the 1280×720 (full 720p) video (and sound) output over HDMI. In addition to this, the shield features a memory card slot which could house memory card on which game assets like sounds, images and sprites could be stored.

Some highlight features of the dazzler include:

GPU: BT815
FPGA: Xilinx Spartan-6
Video output: 24-bit HDMI at 1280×720 (720p) with audio
Storage: microSD slot
Extra input: two Wii Classic controller ports
Programming: Arduino and CircuitPython, with lots of samples
Console output: built-in with ANSI support
Open source: full stack: hardware, firmware, and software

According to James Bowman,

“the Dazzler is ideal for game designers using Arduino or CircuitPython, makers who want rich, responsive data and text visualizations, and perfectionists who want excellent video output for their Arduino project”.

The dazzler is totally open source, so all project resources including schematics and firmware will be made available.

The project is currently being prepped for a crowdfunding campaign on Crowdsupply. You can sign up on the project page to receive updates and be notified when the project launches.

Current Sources

Introduction

In the continuity of the Voltage Sources tutorial, we present in this article the Current Sources, which are the second type of electric sources we will look at.

Similarly to what has been done for the voltage sources, we will first introduce the concept of ideal current sources where their particularities and characteristics are discussed.

In real circuits, however, ideal current sources cannot be found as some paradox and impossibilities appear with this model. We distinguish these practical sources as real current sources and we will see what are their differences with the ideal model. The interconnection rules between two or several current sources are also discussed further in the same section.

Finally, the last section details the dependent current sources which are voltage or current-controlled current sources.

Presentation

An ideal current source is a device that can supply a constant and stable value of current regardless of the voltage that must be provided to a specific output load. The ideal current sources are represented by a double circle or an arrow within a circle such as illustrated in Figure 1 below:

fig 1: Ideal current source supplying a load of impedance Z (left) and its associated voltage/current characteristic (right)

The characteristic of an ideal current source is sometimes represented I=f(V) as the representation above in Figure 1 is, strictly mathematically speaking, not a function but a distribution.

Real current sources

The internal power losses that take place in a current source can be modelized by a resistor (R_S) associated in parallel. The I/V characteristic is not anymore flat but, such as for voltage sources, is corrected with a slope of value -1/R_s such as illustrated in Figure 2:

We can note that an ideal current source is equivalent to a real source which resistance R_S tends to +∞ (open circuit).

Connection rules

In this subsection, we highlight the fact that some connection rules are necessary to keep in mind when integrating current sources in a circuit.

First of all, the terminals of a current source must not be placed in an open circuit:

fig 3: Current source in open circuit, forbidden connection

The resistance of an open circuit is +∞, when the source provides a current that is not equal to zero, the voltage quantity tends to +∞, which is not possible. In practice, the voltage will increase until its breakdown value, forcing the air/vacuum between the source terminals to become conductive. This phenomenon often leads to the destruction of the source or at least one of its components.

Moreover, the series connection of two or many current sources is also proscribed, even if both sources supply the same current value.

fig 4: Current sources in a series configuration, forbidden connection

The reason why this type of connection is not allowed is that an equivalent circuit cannot be predicted: will the sources add, or only one will effectively work?

The current in a branch of a circuit can only take one value, there cannot be an overlay of many currents.

Finally, the parallel association of current sources is absolutely allowed and recommended to obtain a higher output current:

fig 5: Current sources in a parallel configuration, allowed connection

As shown in the second circuit in Figure 5, the values can also be subtracted if one of the sources is oriented in the opposite direction.

In a parallel configuration, the output current is the algebraic sum of the current sources involved in the supply process.

Dependent sources

In the previous sections, an independent current source has been presented and their value is fixed and depends only on the source’s design.

The current value of dependent current sources can be tuned with an external parameter. There are two types of dependent current sources: Voltage Controlled Current Sources (VCCS) and Current Controlled Current Sources (CCCS). In a circuit diagram, current dependent sources are symbolized by an arrow shape (in the direction of the current) surrounded by a diamond pattern:

Voltage Controlled Current Source

For this type of dependent current source, the nature of the input (voltage) is different than the output (current), the linking factor is labeled σ=1/R and represents a conductivity in Siemens (S) or Ω^-1.

We illustrate what a simple circuit containing a VCCS can look like in Figure 7 and show how to compute its input.

Since the voltage source V₁ supplies a voltage divider 1 kΩ/1 kΩ, the input of VCCS is given by V_IN=V₁/2=5 V. Since the gain of the VCCS is 0.2 S, the output current of the dependent source is I_S=0.2×V_IN=1 A. The output voltage is simply computed by applying Ohm’s law to the resistor R₃, we obtain V_S=I_S×R₃=200 V.

An example of VCCS is the MOSFET amplifier which is a voltage-effect-based transistor:

fig 8: Example of VCCS, the MOSFET supplies an output load R_L

As a VCCS, the MOSFET amplifier takes as input a voltage known as gate voltage and delivers an output current known as drain current.

We can affirm that a MOSFET is indeed a current source after looking at its characteristic I_D=f(V_DS):

fig 9: Output characteristic of a MOSFET

Depending on the command gate voltage (V_GS), the characteristic of the MOSFET amplifier becomes flat after a certain value of the output voltage V_DS. This characteristic in the saturation region is typical for a current source.

Current Controlled Current Source

In the case of CCCS, both the input and output are of the same nature (currents), the gain is, therefore, a dimensionless quantity labeled k.

We illustrate again a similar circuit that integrates a CCCS in order to clarify how to retrieve the output quantities:

The input current controlling the CCCS is here given directly by Ohm’s law: I_IN=V₁/(R₁+R₂)=5 mA. The output current is obtained by multiplying the input current by the gain k, I_S=k.I_IN=3 mA. Finally, the output voltage is again given by applying Ohm’s law to the resistor R₃, V_S=I_S×R₃=0.6 V.

Examples of CCCS are bipolar junction transistors (BJT)-based amplifiers, the reader can refer to the tutorials about Common Emitter Amplifier and Common Collector Amplifier in order to get more details.

Figure 11 is a plot of the output characteristic in the collector branch (C) for several command base currents (I_B):

We recognize again a flat I/V function after a certain value of voltage, typical for a current source, exactly such as for the MOSFET amplifier.

Conclusion

In order to conceptualize current sources, we have first presented ideal current sources that are not real devices but rather an ideal construction. Ideal current sources provide a constant and stable output current value regardless of the value of the voltage across the output load. They are identified by a flat I/V characteristic which presumes than an infinite amount of power can be provided.

Real current sources, however, present a light slope in their I/V characteristic in order to account for the internal power losses. The value of this slope is given by the conductivity of the source resistance placed in parallel with the source. The source resistance is not physically present in the device but it is rather a way to explain and simplify the calculations.

Moreover, we have seen that some connection rules must be taken into account when designing circuits that include current sources. Placing the current source in an open circuit and associating in seres two or more sources is not recommended. The parallel association is, however, acceptable since it is a useful technique that can increase the output current.

Finally, we have seen that some special current sources can be controlled by an external quantity of the circuit. They are known as dependent sources and for current sources, two types exist:

Voltage Controlled Current Sources (VCCS)
Current Controlled Current Sources (CCCS)

Typical examples of current dependent sources are MOSFETs (VCCS) and BJT transistors (CCCS).

ON Semiconductor Low Dropout (LDO) Linear Voltage Regulators

Posted on 18 June, 2020 by mixos

Delivering LDO products in high performance, low power, small form factor solutions to enhance end products

ON Semiconductor’s portfolio of Low Dropout (LDO) Linear Voltage regulators can operate as precision current regulators providing highly stable and accurate voltages with low noise, high PSRR, low dropout, and a very low quiescent current consumption. They provide a wide range of input voltage options with fixed and adjustable output voltage. Available in single and dual output configuration.

Key features

Small size – Industries smallest form factor to performance ratio
Low noise / High PSRR – Market leading PSRR performance
Long battery life – Low Iq to Extend Battery Life
Wide Input Voltage – 1.0V to 700V input available

In addition to their robust design and high reliability, the portfolio offers a variety of protections, making them virtually blow-out proof including overcurrent protection, overvoltage protection, overheat protection, and safe area compensation. Aside from a combination of ideal performance characteristics above, the portfolio is also offered in a variety of package sizes to match specific application requirements for applications such as industrial, consumer, portable & wireless (cameras, tablets, wireless handsets, and smartphones), IoT, and automotive.

Boonton PMX40 40GHz RF Power Meter for USB-connected RF Power Sensors

Posted on 18 June, 2020 by mixos

The PMX40’s intuitive, multi-touch display provides a standalone solution for capturing, displaying, and analyzing peak and average RF power in both the time and statistical domains for up to four RF channels.

Saelig Company, Inc. has introduced the Boonton PMX40 40GHz RF Power Meter which combines the utility of traditional benchtop instrument, the flexibility and performance of modern USB RF power sensors, and the simplicity of a multi-touch display. It utilizes the excellent performance and capabilities of the external Boonton RTP and CPS families of USB RF power sensors which offer 3ns rise times and 195 MHz of video bandwidth. They can make accurate measurements virtually independently of signal modulation bandwidth. Up to four USB sensors can be connected for multi-channel power measurements. Independent or synchronized multi-channel measurements of CW, modulated, and pulsed signals provide great flexibility in a benchtop unit without the need for PC control. This makes it ideal for use in ATE/rack-mount setups.

The PMX40’s intuitive, multi-touch display enables fast configuration of the sensors, as well as easy access to measurement and analysis tools, providing a standalone solution for capturing, displaying, and analyzing peak and average RF power in both the time and statistical domains. The meter also incorporates a test source to verify sensor operation.

For simple, intuitive measurements of repetitive waveforms, the PMX40 Continuous Mode of operation provides a numeric display of average, maximum and minimum signal powers. Analysis of fast-rising single pulses or pulses with short pulse repetition intervals (PRIs) requires an instrument with sophisticated trigger and data acquisition capability; with Pulsed Mode, more than 16 pulse parameters can be measured. In Statistical Mode, the PMX40 plots the Complementary Cumulative Distribution Function (CCDF). The CCDF plot shows the rate of occurrence of a specific crest factor for signals, such as those used in 5G, 4G/LTE, and Wi-Fi applications.

Characterization and compliance testing of Wi-Fi and LTE chipsets and devices involves significant challenges for design and test engineers. With multiple-input, multiple-output (MIMO) architectures and channel bandwidths up to 160 MHz, testing is complex, especially when measuring RF power per channel and time alignment between channels. The PMX40 enables packet power measurements to be performed independently on multiple synchronous or asynchronous transmit chains with a common time-base shared among sensors. Design, verification, troubleshooting, and maintenance of secondary surveillance radar (e.g. IFF-based radar) has never been more demanding. The PMX40 can be used to easily, accurately capture SSR waveforms. Markers enable measurements on specific portions of the waveform. As a benchtop meter, the PMX40 provides a standalone solution for capturing, displaying, and analyzing peak and average RF power in both the time and statistical domains through an intuitive, multi-touch touchscreen display. Connecting a PC adds additional software capabilities.

Key Features

Capture/display/analyze peak and average power
Frequency range from 4 kHz to 40 GHz
Industry-leading video bandwidth (195 MHz) and rise time (3 ns)
Industry-leading 100,000 measurements per second
Industry-leading 100 ps time resolution
Synchronous multi-channel measurements (up to 4 channels)
Sensors can be used as standalone instruments

Made by Boonton Electronics, a recognized leader in high-performance RF test instrumentation and sensors, the Boonton PMX40 40GHz RF Power Meter is available now from Saelig Company, Inc. their USA technical distributor.

NVIDIA Jetson TX2 AI Computing Platform for AIoT Applications

Posted on 18 June, 2020 by mixos

IBASE Technology Inc, a world-leading manufacturer of industrial motherboard boards and embedded computing solutions has revealed its latest EC-3200 AI computing platform that is based on the cutting-edge power-efficient and high-performance NVIDIA Jetson Tegra X2 (TX2) processor. The NVIDIA Jetson TX2 pairs a dual-core Denver 2 alongside a quad-core ARM^® Cortex^®-A57 processor and provides 256 CUDA cores on the NVIDIA’s advanced Pascalä GPU architecture with up to 1.33 TFLOPS, delivering exceptional AI performance.

Designed to operate under an extended temperature range from -20°C to +60°C, the EC-3200 leverages the integrated GPU-computing power of the Jetson TX2 platform in building edge inference servers to analyze and better manage real-time traffic flow in smart cities or to optimize the efficiency of operational processes in intelligent factories.

“Current edge and cloud-based AI products require better computational and video analytics capability to perform demanding real-time data processing and overcome latency issues,” said Wilson Lin, Director of IBASE Product Planning Department. “The EC-3200 is no doubt a durable solution, especially built with a fanless design for non-stop operation, and takes advantage of the GPU-accelerated parallel processing of NVIDIA Jetson TX2 to handle data-intensive and mission-critical workloads with power efficiency and unmatched reliability.”

With dimensions of 127(W) x 137(D) x 46(H) mm, the EC-3200 comes with 8GB LPDDR4 memory and 32GB eMMC storage on board. To connect to essential peripherals, front I/O interfaces provide a GbE, an HDMI (1.4), two USB 3.0 and two USB 2.0 ports, while a DB9 connector (For RS232 or CAN bus), a Micro USB slot, as well as an external 10-pin GPIO port are located on the right side. The two M.2 expansion slots are designed to support optional SSD storage (M2280) and WAN module (E3042). The system is outfitted with a total of four external antenna ports to enhance throughput and connection reliability in outdoor environments. The OS is based on a custom made Ubuntu 16.04 with Jetpack 3.2.1 and L4T 28.2.

EC-3200 FEATURES:

NVIDIA Jetson TX2, Quad Core, 64-bit, 256 CUDA cores
8GB Memory / 32GB eMMC 5.1 / Single GbE
2x M.2 socket (M2280 & E3042), support SSD/WiFi/BT/LTE
Fanless design with operating temperature range from -20°C to +60°C
Designed for wall-mounting and DIN rail mounting
Custom made BSP based Ubuntu 16.04, Jetpack 3.2.1 and L4T 28.2

For more information, please visit www.ibase.com.tw

Sam Controllers about to Launch Power H Mini V2 Driver for DC Motors

Posted on 18 June, 202018 June, 2020 by Tope Oluyemi

Sam Controllers are set to release Power H Mini V2 Driver for DC Motors. This Power H Mini V2 H-bridge provides a 12A Peak current, inbuilt pulse width modulation, and plug and play drivers. In 2018 Sam Controllers released the open-source Power H Mini H-bridge, which said to enable a lot of flexibility for DC motor applications. The 2018 tiny board had a voltage range of 4V to 28V, also has a peak current of 12A and a pinout and Interface similar to A4988, DRV8825, and other similar versions. Sam Controllers will be launching the new version which is Power H Mini V2 board, which offers extremely low heat resistance, and advanced energy recuperation.

In the area of robotics application, the energy regains means that motors have much sharper, more controlled acceleration curves, and also breaks becomes faster and uniformly without waste of heat on the controller. The Power H Mini retains the peak current of 12A like its older version, it has two-wire control system and inbuilt PWM (Pulse width Modulation). It is made for full-bridge control of a single DC motor and two half bridges can control two motors, additionally, three motors can be controlled using mechanically dependent settings. The board is further equipped with an automotive-grade STMVNH7100AS H-bridge, and it has a similar board size with a 15mm x 20mm dimensions since it is a DC motor driver, it competes in use with H-bridge motor drivers based on the L298 or BTS7960 transistor design which is always produced in a module 2-3x, and it also integrates a dual inflexible high-side driver also having two low side switches.

Power H Mini V2 Driver Specs includes:

The Power H Mini V2 has a voltage range of 4V – 28V, it has up to 5V logic level on IN pins, having a peak current of 12A, and up to 20KHz for PMW operations.
The Power H Mini board provides overvoltage clamp/protection, heat shutdown and standby mode, and low standby power utilization.
The Power H Mini V2 has MultiSense diagnostic use, analog moto current response, output short to VCC (Voltage Common Collector) detector. Output protection from short to earth and short to VCC, and it can be added in a custom controller design.

Sam Controller is ready to crowdfund the Power H Mini V2 soon, the date of crowdfunding, and the price of the board will be released soon also.

HV Nixie DC-DC Switching Power Supply using MAX1771

Posted on 17 June, 202018 June, 2020 by mixos

Nixie tubes need about ~180Vdc to light up and thus on most devices, a DC-DC converter is needed. Here we designed a simple DC-DC switching regulator capable of powering most of Nixie tubes. The board accepts 12Vdc input and gives an output of 150-250Vdc.

The module is based on the MAX1771 Step-Up DC-DC Controller. The controller works up to 300kHz switching frequency and that allows the usage of miniature surface mount components. In the default configuration, it accepts an input voltage from 2V to Vout and outputs 12V, but in this module, the output voltage is selected using the onboard potentiometer and it’s in the range 150-250Vdc.

HV Nixie DC-DC Switching Power Supply using MAX1771 – [Link]

MI/O- ATmega328 Based Smart Watch By Markus Bindhammer

Posted on 17 June, 202021 June, 2020 by Tope Oluyemi

Wristwatches are an integral part of our dressing, and also help us plan our day to day activities, making sure we don’t miss meetings, gym, exams, parties etc. These days, a good looking watch speaks volumes about the wearer, because it’s one of the most noticeable accessories a person wears. We have seen smartwatches taking over the conventional analog watches gradually, due to a host of features smartwatches offer. To this end, Markus Bindhammer has committed to the design and production of his own, slimmed-down “smartwatch” called the MI/O, which looks quite different from conventional smart watches. We can visibly see the components it is made of. It features a Microchip ATmega328 MCU at its core, with its primary aim at functionality rather than fashion.

The MI/O functions by powering down the OLED display and ATmega, rather than dropping the controller into a low-power mode. Unlike other watch designs where the microcontroller is put into sleep mode, MI/O completely switches off everything except the RTC when the watch is not in use. This method of power control is remarkable, and effective, because there is a high level of difference between the lowest of power modes, and actual shutdown in almost entire MCU, so utilizing an external low-power mode of arranging things is ideal. When you turn the MI/O over, you find some extra functionality that enables you to input your own feature sets, with the MI/O acting as the core for any creations you have in mind.

When you look at the rear of the MI/O, it features an array of connectivity, which includes GPIO, I2C, SPI, and the UART of the ATmega can be found on the headers that are visible from the middle of the boards back face. In one of Bindhammer’s demonstration, we see him showing a wing which enables MI/O to be powered externally by a Micro USB connection and a reading light extension. These days, watches are fitted with WiFi, cameras, social media features, and health apps. However, MI/O is built for basic functions.

Bindhammer says:

“The watch itself is finished as far as the hardware is concerned and is in pre-production. However, there is still some work to be done on the software side. In the future I would like to develop more add-ons for MI/O.” About sales, Bindhammer says “I am planning an Indiegogo campaign with MI/O. I’ve teamed up with makerfabs. They will assemble the wristwatch (100 pieces for now). Meanwhile I designed the packaging, a folding box 94 x 94 x 14 mm, 4-color print, glossy look, printed in Germany.”

For now, there are no sources from Bindhammer, but you can find more information on his project page.

Masterkey – USB WiFi Keylogger

Posted on 17 June, 2020 by Emmanuel Odunlade

A Keylogger, a short form for keystroke logger, is a type of monitoring or digital surveillance tool (software or hardware) that is primarily used to record (log) keyboard keystrokes made by the user of the host computer. They are more advanced in recent times and are sometimes also used to log mouse clicks, touches, etc., typically in a covert manner that ensures the user doesn’t know their actions are being monitored.

While the most popular use of keyloggers is in malicious applications to perpetrate unlawful acts like; collecting personal information like credit card numbers, user names, passwords, etc., legitimate uses for them do exist with, parents using it to monitor their kid’s online activity, ethical hackers/law enforcement agents using it to analyze and track incidents linked to the use of personal computers, and employers using them to ensure employees stay on task.

While software-based keyloggers are more popular because they are less conspicuous, hardware-based keyloggers also have their applications, a good example of which is the employer-employee scenario described above. There are a lot of DIY hardware-based keyloggers on the internet but the recently shared USB WiFi Keylogger by KoKo is one of the most interesting I’ve seen in a while.

The USB WiFi Keylogger is capable of sniffing keypresses sent from a USB keyboard to a computer and presenting them to the attacker/monitoring entity over WiFi.

The device was designed to be a plug and play device. Simply plug the target USB Keyboard into the female USB port of the keylogger then plug the USB Keylogger into the target computer. After about five seconds, any keys pressed on the keyboard will be logged by the keylogger and passed through to the target computer.

The keylogger is based on the MAX3421EE USB interface and combines an ESP8266 with an Atmega32u4 microcontroller.

To allow external access to the key presses, it is stored in the file system of the ESP8266 which can be accessed over WiFi via the device’s web interface. To access the web interface the monitoring entity needs to be within the range and connected to the WiFi access point created by the USB Keylogger. With this in place, the monitoring entity can navigate to a specified URL and see the logged keypresses displayed withing the textbox on that page. To start a fresh log, the user can clear the previously logged keystrokes using a clear button located at the bottom of the page.

Asides from logging keystrokes, the Masterkey USB WiFi Keylogger can also be used to perform a sort of attack known as Keystroke injection attacks. This can be done via the web interface by navigating to the Live Execute tab at the top of the screen. Through the Live Execute tab, the user can write, run, and save keystroke injection scripts written in ducky script. Users can also save scripts to be used later or upload prewritten scripts to be executed on Masterkey.

For security and customization purposes, the Masterkey has a Settings tab that allows users to customize the appearance of the device and secure the wireless access point. Users are able to change elements like the APN’s SSID, APN’s password, the Channel on which the access point will be broadcasted, and the Hidden elements which will tell the master key whether or not to broadcast the access point.

The Masterkey runs a modified version of spacehuhn’s wifi keylogger code with a few more bells and whistles, and it supports over-the-air firmware update for the ESP8266’s firmware using ElegantOTA.

More information about the Masterkey can be found on the project’s GitHub repo which also holds all the resources you will need to build your own version of the device. KoKo has done quite a lot of work on Hardware keyloggers and you can find more information on diverse kinds of Keyloggers a repo dedicated to them.