The Important Role of Microcontrollers in Technology and Engineering - Lab Report Example

1. Table of Contents Table of Contents 0 2.List of Figures 3.List of Tables 2 4 3 5.Introduction 4 6.What is a microcontroller? 6 7.Advantages of microcontrollers 10 8.Common types of microcontrollers 11 8.1. Arduino Uno 14 8.2.Arduino Leonaldo 15 8.3.Arduino Due 16 9.Example of the use of microcontroller timer 17 10.Applications of microcontrollers 19 10.1.Vehicles 19 10.2.Spacecraft 19 10.3.Urban crisis management 20 11.Conclusion 20 11.1.Summary 20 11.2.Future development of microcontroller 21 12.References 22 2. List of Figures Figure 1: Simple Computer Architecture [11] 5 Figure 2: Scheme of a typical microcontroller [1] 6 Figure 3: A read only input port permits microcontroller to sense external digital signals 8 Figure 4: Scheme of interaction of microcontroller elements [1] 8 Figure 5: How the Microcontroller CPU works 9 Figure 6: The circuit representation of Arduino R3 front [11] 14 Figure 7: The Front view of Arduino Leonaldo with header [11] 15 3. List of Tables Table 1: Execution of a simple addition of 4+5 9 Table 2: summarized qualities of microprocessor memory [3] 11 Table 3: The Common Features of Arduino Uno [11] 15 Table 4: The Main features of Arduino Leonardo [11] 16 Table 5: Summary of Arduino Due features [11] 17 4. Abstract The goal of this research is to emphasize the important role of microcontrollers in technology and engineering. In this research, we define concepts of microcontrollers along with their components such as memories, timers, analog-to-digital converter, etc. We discuss the advantages of microcontrollers and their common types. We talk about how the common types gain their popularity among other microcontrollers particularly Arduino Uno, Arduino Leonardo, and Arduino Due. Also, a table that compares popular microcontroller platforms is considered. Moreover, we provided a basic C programming example to turn an LED on and off in 10 milliseconds. We talked about some applications where microcontrollers are used. Also, the directions and trends of future development of microcontrollers were analyzed. 5. Introduction Current century is not only the information century but also the century of automation. Automation is one of the global forces, which are currently reshaping the world. Unlike in the past, the barriers that existed between information, communication and automation technology are becoming a forgotten in the past especially within the operational field. The significance of automation in the process industry has risen over the recent past with the greatest demand being experienced in the chemical industry, petrol chemical industry, and power production plants where automation is in high demand to change the face the processes involved [1]. In industries, process control ascertains that the plant continues to run predictably and within optimum profit, thereby providing improved outcome quality, increased productivity, and speeding system alteration and retrofitting. Compared according to regions, North America was the leader in process automation market with China reporting as the fastest growing center for automation in Asia and the world. For manufacturing plants in these countries, the production process has to be more flexible, smaller, productive, and has location determined by closeness to customer or raw materials. In the automation industry, microcontrollers play an important manufacturing role. Prior to the invention of microcontrollers, the operation of large electromechanical systems was through huge machines such as automobile engines and furnaces. These machines were responsible for performance and efficiency optimization. The first microprocessor was developed in 1970s by Integrated Electronics (Intel) for a Japanese client company, Busicon. However, when this company declined to purchase the chipset, Intel introduced the chipset into the market as a general purpose micro-processing system 4004. The market reception was a success prompting the second generation microprocessor 8008 in 1974. Later Motorola joined and a wider range of microcontrollers distributed to the market. Today is virtually impossible to work with electronics without microcontrollers. Simple electronics with microcontrollers are ovens, clock radios, toasters, lawn watering, and refrigerators. For sophisticated uses, microcontrollers are found in spacecraft, robots, life supporting machines, and ocean vessels. Although microcontrollers’ functions are similar to those of computers, they are specialized microcomputers and not computers. The basic computer architecture comprises of control logic, registers, instruction register, instruction memory, Arithmetic Logic Unit, Input/output and accumulator as illustrated in figure 1 below. Figure 1: Simple Computer Architecture [11] Microcontrollers, in short, are digital integrated circuits which have similar functions to computers but are designed specifically for automating different devices. With the help of microcontrollers, engineers have been able to create and devised a variety of home appliances, industrial machines, customized devices, etc. Microcontrollers are currently invaluable for the development of engineering. Having knowledge of microcontroller is essential for engineering students. Microcontrollers versatility enables them to add a lot of control and power to any engineering designs [7]. Most of today’s electronics have microcontrollers embedded in them. As a result, microcontrollers currently can be found everywhere, starting with alarm clocks and toasters, ending with devices for space exploration and more. This is a reason why engineering students should have knowledge of microcontrollers and learn to program them to maintain a level of competence and gain advantages from using them. In the technological space of microcontrollers, there have been a lot of researches and books written. For instance, references [1−7] discuss a lot of aspects about microcontrollers starting with concepts and elements, ending with advantages and programming. There are also other researches that discuss the manufacturing features that could be applied to microcontrollers such as the EEPROM memory which allows erasing and rewriting the programs stored in the microcontroller [8]. Today, technology is used in a lot of applications in our lives. In the area of transportation, microcontrollers add new technologies and features to automobiles such as road-conditions warnings, communication system and safety systems [2−9]. In addition to that, microcontrollers can be used to address traffic and safety problems to provide comfort road to us [5−10]. In Section 2 of this research, we define the concept of a microcontroller. We describe the difference between the types of memories microcontrollers have and the CPU of microcontrollers. In Section 3, we consider some of the advantages of microcontrollers. In Section 4, we discuss the types of microcontroller and also provide a table that compares popular microcontrollers’ platforms in terms of price, starter kit, processor, processor speed, Analog pins, etc. In Section 5, we demonstrate the ease of developing DIY solutions by programming a simple device to turn an LED on and off. In Section 6, we discuss the common applications where microcontrollers are used in such as automobiles. Section 7 is the conclusion which summarizes the research and also analyzes the future developments of microcontrollers and the evolution of their use. 6. What is a microcontroller? A microcontroller is a minicomputer which commonly includes the following elements: memory chip, processor core and peripherals for programmable inputs and outputs. The simplest definition of a microcontroller is a small device that controls gadgets, and machines among other things. This device takes the form of an integrated circuit that constitutes a memory and a central processing unit (CPU) just like a computer, but with no input components like a mouse or keyboard [2]. The manufacturers customize the controllers by adding different elements such as random access memories, timers, and analog-to-digital (A/D) converters to their controllers [1]. Microcontrollers usually come with the software that can be used to program the device. While “conventional” computers are general-purpose devices, microcontrollers can be referred to as the computers with a special purpose. The scheme of a typical controller is shown on Figure 1. Figure 2: Scheme of a typical microcontroller [1] In Figure 2, ROM denotes the read-only memory which is used to store the program for the microcontroller, and RAM is the chip with random access memory used for storing the results of calculations, variables and other temporary information at the program runtime. The difference between these two types of memory is the dependence on the power supply: ROM stores its content permanently while the content of RAM is cleared when the device’s power is off hence making it volatile. RAM operation begins with the operating system loading the application software into it when powered on and the CPU then runs it. While computers have gigabytes of RAM, most microcontrollers have in-built 256 bytes RAM. As for ROM, programming is done during manufacturing and it can only have the values specified during programing. Although it cannot be changed, ROM in microcontrollers can be done as many times as possible since programs stored I it do not change over long durations of time. In most case, ROM is perceived as a waste of address space hence not preferred by most people. Consequently, in most controllers, Electrically Erasable Programmable Read Only Memory (EEPROM) memory is installed: this type of memory allows rewriting the programs which are stored on this chip [6] and the biggest advantage is that no part needs to be removed from the circuit to reprogram it. Finally, for much faster ROM, Flash EEPROM is used in microcontrollers and only few hundreds of microseconds are needed to program each byte making it much faster than EEPROM. The drawback is that all content has to be removed before it can be reprogrammed. The central processing unit (CPU) is located in the center of the controller typically includes arithmetic-logical unit (ALU), accumulator and program decoder. The main role is to run the program supplied by the microcontroller designer and in each version of Microcontrollers, the CPU varies making it essential to know the version one requires and how to deal with it. RAM memory is commonly divided into registers: parts of them are special purpose registers used for storing the controller’s specific data while other parts are general purpose registers where program variables and other program data can be stored. Each controller has some input and output (I/O) ports which provide possibilities for interacting with the external world. I/O ports and methods might significantly vary for different controllers; COM and USB ports are commonly used as I/O variants. The most common I/O ports in microcontrollers are parallel ports. Parallel I/O makes it possible for the microcontroller software to interact with exterior devices. Parallel indicates that the ports can all be accessed simultaneously. The parallel port that permits the microcontroller to read external digital signals is referred to as input port and is read only. Consequently, as read cycle accesses the input ports, the values at the inputs during that particular time are returned. For instance, from the figure 3 below, the tristate driver forces the input signal onto the data bus in the course of the read cycle from port address while the write cycle does not affect the input port. As a result, the read digital values are copied to the microcontroller. Figure 3: A read only input port permits microcontroller to sense external digital signals However, an output port can provide both read and write roles just like an ordinary memory in the form of a readable output port. During communication with external devices, write cycle affects the values on the output pins. First, microcontroller situates information on the data bus for clocking into D-flip flops. The read cycle then returns the values present on the port pins. Low-level programming languages used to program microcontrollers include Assembly, C, and Basic in which simple instructions are written in the order of execution. Microcontroller’s mode of communication can be parallel or serial depending on the distance between devices. For closely situated devices, parallel communication occurs but for longer distances, parallel communication is the best solution.The major components of the microcontroller interact in the following way as shown in Figure 4. Figure 4: Scheme of interaction of microcontroller elements [1] The operation of a microcontroller operates commences with loading the completed program into the microcontroller by turning off the power supply. Upon turning on the power supply, control logic disables other circuits but enables the quartz crystal. Power supply remains until maximum voltage where the oscillator frequency stabilizes, special functions registers in RAM take the bits indicating the circuit states, and all pins are configured as inputs. Then, the program counter is set to zero and increments after instructions from a given address are sent to the decoder. The new PC value is the memory address for the next instruction for CPU execution. After decoding, the arithmetic and logic unit performs all logic calculations while the CPU internal registers stores the results. The figure below shows how the CPU works while the table represents simple microcontroller execution of a simple addition: 4+5. Figure 5: How the Microcontroller CPU works Address Instruction (a binary code value identifying the action to take) 0000 Read the value at memory address 0100, store in Register 1 0100 Read the value in memory address 0101, store in Register 2 0200 Add the value in Register 2 to the value in register 1 and save the result in register 1 Address Data 0100 4 0101 5 Table 1: Execution of a simple addition of 4+5 7. Advantages of microcontrollers Microcontrollers have numerous advantages, which have contributed to the increase of their popularity. First of all, microcontrollers can be programmed to fulfill different functions, the most common functions of which are information-processing, control of the device, generating signals, etc. Controller CPUs are fast and can respond to commands almost 1,000 times faster than mechanical systems, and can accept inputs from various channels [1]. Due to this feature, microcontrollers are currently widely used for creating real-time control and monitoring systems. Another advantage of microcontrollers is their size. The manufacturers of microcontrollers locate all components on the same chip and use cutting-edge technology for producing the components of microcontrollers. As a result, the controller can be embedded even into the smallest devices. In addition to that, microcontrollers are cheap. Compared to electromechanical predecessors, microcontrollers are cost effective especially if they can be reprogrammed where the designed application fails to work effectively or where its application changes. With Flash, EEPROM, and EPROM, any changes can be implemented straight forward on the used control law (summarized in Table 2). Additionally, including numerous components on one IC, component, and board area result in significant savings given that much lower specifications are required unlike low-power general purpose microprocessors. For instance, microcontrollers require less electrical energy compared to using individual components separately, thus making them energy efficient since only 5V supply is required. The cost of the integrated circuit itself is under $10 for simple controllers, and the related systems of development or kits cost is around $100 [1]. Due to this feature, microcontrollers are widely used by both large manufacturing companies and by individual researchers or even hobbyists. Table 2: summarized qualities of microprocessor memory [3] Today, the design and simulation of microcontrollers make it possible to guarantee precision of coding and system performance. Additionally, typical microcontroller applications involve tasks that are too minute and repetitive such that humans can reproduce quick and consistent motions, while increasing productivity. Unlike in the past where assembly language was used for programming, C compilers are accessible that is used on most microcontrollers. 8. Common types of microcontrollers Modern microcontrollers do not require brazing because they contain all major components of the circuit on the same chip. The variety of microcontrollers allows choosing the right chip and developing a customized device without extra effort. A significant advance in the development of microcontrollers was reached due to the creation of open platforms such as Raspberry Pi and Arduino [5]. When microcontrollers first appeared, engineering companies such as Intel protected their inventions and set high prices for their platforms for programming microcontrollers. As a result, microcontrollers were not readily available for the general public. However, when the open source platforms like Arduino emerged, millions of engineers and “do-it-yourself” fans became eager to purchase the microcontroller and to start different projects [4]. Figure 3 shows the first version of Arduino microcontroller. Figure 3 − First version of Arduino Microcontroller [4] The success of first open-source microcontrollers stimulated their rapid development, and it is now possible to choose a microcontroller with a starter kit in accordance with different parameters. Microcontrollers, which are readily available to the public, differ in the number of features, memory storage size, I/O ports, processor speed, the number of analog and digital pins, the type of memory, and in the type of programming language and expansibility. Currently microcontrollers are not only changing the world of engineering, but also changing the world of education. Many educational institutions nowadays purchase Raspberry Pi or Arduino for their students, and encourage young researchers and engineers to experiment and create new inventions [4]. Table 1 shows the comparison of the most popular microcontroller platforms and versions available today. Micro-controller name Arduino Uno Arduino Leonardo Arduino Due Mint-Duino Net-duino 2 Net-duino Plus 2 Raspberry Pi Beagle-Bone Black Price $29.99 $24.99 $49.99 $24.99 $34.99 $59.99 $39.99 $45.00 Starter Kit $64.99 $64.99 $64.99 $64.99 $99.99 $99.99 $129.99 In progress Processor ATmega 328 ATmega 32u4 ARM Cortex-M3 ATmega 328 STMicro Cortex-M3 STMicro Cortex-M3 ARM 1176JZF-S ARM Cortex-A8 Processor Speed 16 MHz 16 MHz 84 MHz 16 MHz 120 MHz 168 Mhz 700 MHz 1 GHz Analog pins 6 12 12 6 6 (12-Bit) 6 (12-Bit) 0 (no on-board ADC) 7 Digital pins 14 (6 PWM) 20 (7 PWM) 54 (12 PWM) 14 (6 PWM) 22 (GPIO - 6 PWM) 22 (GPIO - 6 PWM) 8 Digital GPIO 65 GPIO (8 PWM ) Program-ming language Arduino – variant of C programming language Microsoft Visual Basic or C# Any programming language supported by a compatible distribution of Linux Special features Onboard USB controller USB, on-board emulation of HID Support of Android ADK, CAN BUS, USB Host Arduino DIY Micro .Net program-ming framework Micro .Net program-ming framework, Ethernet on board Composite and HDMI output, Ethernet on board, HD Capable video-processor Ethernet on board, USB Host on board, HDMI, 2GB storage on board Table 1 − Comparison of popular microcontroller platforms [4] 8.1. Arduino Uno This microcontroller is found on ATmega328. The main features are 14 I/O pins, a Universal Serial Bus (USB) port, 6 analog pins, a power jack, 16 MHz ceramic resonator, a reset button, and an ICSP header. Basically, Arduino Uno has everything required to support the microcontrollers. All one has to do is attach to the workstation through a USB cable or use an AC-to-DC adapter or battery to power it [11]. Compared to all other microcontrollers, Uno does not comprise of the FTDI USB-to-serial driver. Conversely, the microcontroller comprises of an Atmega16U2 which is programmed to function as a USB to Serial driver converter. In Uno, the power supply is automatically chosen and can be USB connection or external power supply. For the USB connection, power is mostly from a battery or AC-to-DC adapter. When using an external power supply, Uno is stable at 6-20 Volts and les stable at 5volts Pin. Uno’s RAM is 32 Kb, with an SRAM 2kb, and 1K EEPROM. Figure 6 below represents the diagram or Uno R3 and Talble 3 is the summary of Arduino Uno features. Figure 6: The circuit representation of Arduino R3 front [11] Microcontroller ATmega328 Operating Voltage 5V Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V Digital I/O Pins 14 (of which 6 provide PWM output) Analog Input Pins 6 DC Current per I/O Pin 40 mA DC Current for 3.3V Pin 50 mA Flash Memory 32 KB (ATmega328) of which 0.5 KB used by bootloader SRAM 2 KB (ATmega328) EEPROM 1 KB (ATmega328) Clock Speed 16 MHz Table 3: The Common Features of Arduino Uno [11] 8.2. Arduino Leonaldo Arduino Leonaldo board is founded on the Atmega32u4. The microcontroller has 20 digital I/O pins, a micro USB, ICSP header, 16MHz crystal, oscillator, and a reset button. The difference between Leonardo and other Arduino microcontrollers is that it comprises of built-in USB communication, hence no need for another processor since appears a keyboard and mouse when connected to a computer [Boxtall]. The figure 7 below represents the front of Arduino Leonardo with headers, and table 4 represents the main features. Figure 7: The Front view of Arduino Leonaldo with header [11] Microcontroller ATmega32u4 Operating Voltage 5V Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V Digital I/O Pins 20 PWM Channels 7 Analog Input Channels 12 DC Current per I/O Pin 40 mA DC Current for 3.3V Pin 50 mA Flash Memory 32 KB (ATmega32u4) of which 4 KB used by bootloader SRAM 2.5 KB (ATmega32u4) EEPROM 1 KB (ATmega32u4) Clock Speed 16 MHz Table 4: The Main features of Arduino Leonardo [11] 8.3. Arduino Due This microcontroller board is an Atmel SAM3X8E ARM Cortex-M3 CPU.it pioneered the use of a 32-bit ARM and constitutes of 54 digital I/O pins, 4 UARTs, JTAG header, 12 analog inputs, and 84 MHz clock as well as a USB OTG. Caution is required when using Arduino due since the highest I/O pins voltage is 3.3V. Consequently, higher voltages of about 5 V could damage the board. The table 5 below represents a summary of the features of Due microcontroller. Microcontroller   AT91SAM3X8E Operating Voltage   3.3V Input Voltage (recommended)   7-12V Input Voltage (limits)   6-16V Digital I/O Pins   54 (of which 12 provide PWM output) Analog Input Pins   12 Analog Outputs Pins   2 (DAC) Total DC Output Current on all I/O lines   130 mA DC Current for 3.3V Pin   800 mA DC Current for 5V Pin   800 mA Flash Memory   512 KB all available for the user applications SRAM   96 KB (two banks: 64KB and 32KB) Clock Speed   84 MHz Table 5: Summary of Arduino Due features [11] 9. Example of the use of microcontroller timer Microcontrollers create great opportunities for anyone who has a disposition to engineering. With the help of microcontrollers, one can automate different functions and create links between hardware and software. It is reasonable to consider an example illustrating the ease of using microcontrollers for automation purposes. In this section, a simple example of programming a blinking LED which would turn on and off in 10 ms is considered. The use of time control and timers is one of the most frequently used functions of microcontrollers. Such functions make it is possible to solve important tasks such as showing current time, calculating time elapsed, controlling LED brightness as a function of time, controlling the movement and angle of a shaft, receiving data from external sensors at given intervals of time, etc. In the majority of microcontrollers, timers are implemented as counters which are incremented in accordance with the cycle of the embedded clock and prescaler [1]. Depending on the type and design of a microcontroller, these counters have different sizes and can be configured using different prescalers. In this example, the PIC microcontroller, version 16F877, timer will be implemented. This microcontroller has three timers, two of them – Timer 0 and Timer 2 – are 8-bit counter, which their values are between 0 and 255 range. The third timer – Timer 1 – is a 16-bit counter, the values of which are between 0 and 65535 [1]. The counter changes for every given number of clock cycles, and the length of the clock cycle depends on clock frequency. For example, if the microcontroller has 4 MHz clock frequency, and the timer increments every 4 clock cycles by default, this timer; therefore, will make one million steps in a minute. Using prescalers, it is possible to change the timer’s increment. For example, a timer with a prescaler equal to 8 will increment every 4*8=32 clock cycles. In general, in most cases it is optimal to use the highest available value of prescaler to avoid preliminary overflow of timer counter. To calculate the time passed since setting the timer, the following equation can be used: (1) In this equation, d is the timer delay (in milliseconds), t is the number of timer’s ticks, p is the value of the prescaler, and f is the clock frequency (in Hz). From this equation, it is possible to determine the expected delay in milliseconds to calculate time elapsed if needed. It is also possible to determine the exact value of timer counter to start some actions after a predetermined time (e.g. light a LED). For example, if it is necessary to determine the value of timer variable in 10 ms, given that the microcontroller’s clock is set to 20 MHz and the prescaler is set to 8, then, substituting these values into equation (1), one can obtain equation (2): (2) The number of timer’s ticks can be evaluated from equation (2) as: (3) Therefore, a basic C program for launching some action in a given period of time (e.g. turning on and off a LED) can be designed as follows: long d; //delay variable long p; //prescaler variable long c;//clock variable long t;//variable for the number of timer clicks setup_timer_1(T1_INTERNAL | T1_DIV_BY_8); //prescaler of timer 1 set to 8 d = 10; p = 8; c = 20000000; t = (d * c)/(4*1000*p); while (1) { set_timer1(0); //timer 1 value set to 0 while (get_timer1() Read More