Chapter-8_Microcontrollers(2).pdf

Chapter-8: Microcontrollers 1. What is Microcontroller? Microcontroller: The microcontroller is the electronic device. It has processing unit along with fixed sized ROM, RAM, and other required peripheral components. These all the components are embedded on the...

Chapter-8: Microcontrollers 1. What is Microcontroller? Microcontroller: The microcontroller is the electronic device. It has processing unit along with fixed sized ROM, RAM, and other required peripheral components. These all the components are embedded on the single chip. As it has all the components required to process and store data, it is also called as minicomputer or computer on the single chip. Below is the block diagram of the architecture of microcontroller. Figure: Microcontroller on a single chip It is widely used in embedded system. 2. What are the structural components of a microcontroller? Figure: Structure of a microcontroller Any electric appliance that stores, measures, displays information or calculates comprise of a microcontroller chip inside it. The basic structure of a microcontroller comprise of:- CPU – Microcontrollers brain is named as CPU. CPU is the device which is employed to fetch data, decode it and at the end complete the assigned task successfully. With the help of CPU all the components of microcontroller is connected into a single system. Instruction fetched by the programmable memory is decoded by the CPU. Memory – In a microcontroller memory chip works same as microprocessor. Memory chip stores all programs & data. Microcontrollers are built with certain amount of ROM or RAM (EPROM, EEPROM, etc) or flash memory for the storage of program source codes. Input/output ports – I/O ports are basically employed to interface or drive different appliances such as- printers, LCD’s, LED’s, etc. Serial Ports – These ports give serial interfaces amid microcontroller & various other peripherals such as parallel port. Timers – A microcontroller may be in-built with one or more timer or counters. The timers & counters control all counting & timing operations within a microcontroller. Timers are employed to count external pulses. The main operations performed by timers’ are- pulse generations, clock functions, frequency measuring, modulations, making oscillations, etc. ADC (Analog to digital converter) – ADC is employed to convert analog signals to digital ones. The input signals need to be analog for ADC. The digital signal production can be employed for different digital applications (such as- measurement gadgets). Interpret Control- This controller is employed for giving delayed control for a working program. The interpret can be internal or external. Special Functioning Block – Some special microcontrollers manufactured for special appliances like- space systems, robots, etc, comprise of this special function block. This special block has additional ports so as to carry out some special operations. 3. Microcontroller Features: Microcontrollers usually contain from several to dozens of general purpose input/output pins (GPIO). GPIO pins are software configurable to either an input or an output state. When GPIO pins are configured to an input state, they are often used to read sensors or external signals. Configured to the output state, GPIO pins can drive external devices such as LEDs or motors, often indirectly, through external power electronics. Many embedded systems need to read sensors that produce analog signals. This is the purpose of the analog-to-digital converter (ADC). Since processors are built to interpret and process digital data, i.e. 1s and 0s, they are not able to do anything with the analog signals that may be sent to it by a device. So the analog to digital converter is used to convert the incoming data into a form that the processor can recognize. A less common feature on some microcontrollers is a digital-to-analog converter (DAC) that allows the processor to output analog signals or voltage levels. In addition to the converters, many embedded microprocessors include a variety of timers as well. One of the most common types of timers is the programmable interval timer (PIT). A PIT may either count down from some value to zero, or up to the capacity of the count register, overflowing to zero. Once it reaches zero, it sends an interrupt to the processor indicating that it has finished counting. This is useful for devices such as thermostats, which periodically test the temperature around them to see if they need to turn the air conditioner on, the heater on, etc. A dedicated pulse-width modulation (PWM) block makes it possible for the CPU to control power converters, resistive loads, motors, etc., without using many CPU resources in tight timer loops. A universal asynchronous receiver/transmitter (UART) block makes it possible to receive and transmit data over a serial line with very little load on the CPU. Dedicated on-chip hardware also often includes capabilities to communicate with other devices (chips) in digital formats such as Inter- Integrated Circuit (I²C), Serial Peripheral Interface (SPI), Universal Serial Bus (USB), and Ethernet. 4. Types of microcontroller Microcontroller can be categorized on the basis of architecture and service providers. On the basis of architecture the types of microcontroller are: 1. Havard Architecture 2. Von Neumann Architecture On the basis of Service Provider or Vendor the types of microcontroller are: 1. AVR 2. PIC 3. Hitachi 4. Motorola Types of Microcontroller on the basis of Architecture On the basis of architecture the types of microcontroller are: 1) Havard Architecture: In Havard architecture separate storage and signal buses are provided for different set of instructions and data. This architecture has the entire data storage within the CPU and there is no access available for instruction storage as data. This architecture provides simultaneous access to an instructions and data stored inside internal buses of microcontroller. Let's see the block diagram of Havard Architecture: 2) Von Neumann Architecture: This architecture of microcontroller was proposed by scientist John Von Neumann. In this architecture for both instruction and data a single data path or bus is present. Therefore the CPU performs a single operation at a time. It either performs Read/Write operation on data, or fetches a set of instruction from memory. Hence instruction fetch and a data transfer operation cannot occur simultaneously by using a common bus. Let's see the block diagram of Von Neumann Architecture: Types of Microcontroller on the basis of Service Provider On the basis of Service Provider or Vendor the types of microcontroller are: 1) AVR: AVR microcontroller is developed by Atmel service provider, AVR architecture is based on the Harvard architecture. It is based on Reduced Instruction Set Computers (RISC). AVR is not an acronym it is just a name given to the RISC architecture based microcontroller. 2) PIC: PIC microcontroller is also a Harvard architecture based controller. PIC is an acronym stands for "Peripheral Interface Controller". This type of microcontroller supports programming in C, Assembly and BASIC C. 3) Hitachi: Hitachi microcontroller belongs to H8 family of the controller. H8 is name used in large family of 8- bit, 16-bit and 32-bit microcontroller developed by Renesas Technology, founded in an early 1990s within Hitachi semiconductors. 4) Motorola: Motorola microcontroller is highly integrated microcontroller that is used for high-performance data manipulation operation. This microcontroller unit uses a System Integration Module (SIM), Time Processing Unit (TPU) and Queued Serial Module (QSM). 5. PIC and PIC16f877a Introduction PIC Introduction: Peripheral Interface Controllers (PIC) is one of the advanced microcontrollers developed by microchip technologies. These microcontrollers are widely used in modern electronics applications. A PIC controller integrates all type of advanced interfacing ports and memory modules. These controllers are more advanced than normal microcontroller like 8051. The first PIC chip was announced in 1975 (PIC1650). As like normal microcontroller, the PIC chip also combines a microprocessor unit called CPU and is integrated with various types of memory modules (RAM, ROM, EEPROM ,etc), I/O ports, timers/counters, communication ports, etc. All PIC microcontroller family uses Harvard architecture. This architecture has the program and data accessed from separate memories so the device has a program memory bus and a data memory bus (more than 8 lines in a normal bus). This improves the bandwidth (data throughput) over traditional von Neumann architecture where program and data are fetched from the same memory (accesses over the same bus). Separating program and data memory further allows instructions to be sized differently than the 8-bit wide data word. Now we will move to PIC16F877A. PIC16F877A Introduction: Microcontroller PIC16F877A is one of the PICMicro Family microcontroller which is popular at this moment, start from beginner until all professionals. Because very easy using PIC16F877Aand use FLASH memory technology so that can be write-erase until thousand times. The superiority this Risc Microcontroller compared to with other microcontroller 8-bit especially at a speed of and his code compression. The 16F877A is a capable microcontroller that can do many tasks because it has a large enough programming memory (large in terms of sensor and control projects) 8k words and 368 Bytes of RAM. This is enough to do many different projects. 6. Features of PIC16F877A The PIC16F877A CMOS FLASH-based 8-bit microcontroller is upward compatible with the PIC16C5x, PIC12Cxxx and PIC16C7x devices. It features 200 ns instruction execution, 256 bytes of EEPROM data memory, self programming, an ICD, 2 Comparators, 8 channels of 10-bit Analog-to-Digital (A/D) converter, 2 capture/compare/PWM functions, a synchronous serial port that can be configured as either 3-wire SPI or 2-wire I2C bus, a USART, and a Parallel Slave Port. High-Performance RISC CPU  Lead-free; RoHS-compliant  Operating speed: 20 MHz, 200 ns instruction cycle  Operating voltage: 4.0-5.5V  Industrial temperature range (-40° to +85°C)  15 Interrupt Sources   35 single-word instructions  All single-cycle instructions except for program branches (two-cycle) Special Microcontroller Features  Flash Memory: 14.3 Kbytes (8192 words)  Data SRAM: 368 bytes  Data EEPROM: 256 bytes  Self-reprogrammable under software control  In-Circuit Serial Programming via two pins (5V)  Watchdog Timer with on-chip RC oscillator  Programmable code protection  Power-saving Sleep mode  Selectable oscillator options  In-Circuit Debug via two pins Peripheral Features  33 I/O pins; 5 I/O ports  Timer0: 8-bit timer/counter with 8-bit prescaler  Timer1: 16-bit timer/counter with prescaler  Can be incremented during Sleep via external crystal/clock  Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler  Two Capture, Compare, PWM modules  16-bit Capture input; max resolution 12.5 ns  16-bit Compare; max resolution 200 ns  10-bit PWM  Synchronous Serial Port with two modes:  SPI Master  I2C Master and Slave  USART/SCI with 9-bit address detection  Parallel Slave Port (PSP)  8 bits wide with external RD, WR and CS controls  Brown-out detection circuitry for Brown-Out Reset Analog Features  10-bit, 8-channel A/D Converter  Brown-Out Reset  Analog Comparator module  2 analog comparators  Programmable on-chip voltage reference module  Programmable input multiplexing from device inputs and internal VREF  Comparator outputs are externally accessible 7. Different Applications of Microcontroller Microcontroller is termed as “Computer-on-a-Chip“. It is named so, because not only the CPU, but RAM, ROM, I/O ports, Timer/Counter, Serial I/Os all are put together on a single microcontroller chip. Microcontrollers are task specific and are essentially used for making Embedded Systems. The below image shows very few examples for the application of microcontrollers in our day-to-day used products. Actually wherever we need electronic automation, we use microcontroller. The application area of microcontrollers is so vast, probably we won’t be able to finish up listing them all. Here we will categorize different application areas of microcontrollers:  Figure: Application of microcontroller i. Consumer Electronics Products: Toys, Cameras, Robots, Washing Machine, Microwave Ovens etc. [any automatic home appliance] ii. Instrumentation and Process Control: Oscilloscopes, Multi-meter, Leakage Current Tester, Data Acquisition and Control etc. iii. Medical Instruments: ECG Machine, Accu-Check etc. iv. Communication: Cell Phones, Telephone Sets, Answering Machines etc. v. Office Equipment: Fax, Printers etc. vi. Multimedia Application: Mp3 Player, PDAs etc. vii. Automobile: Speedometer, Auto-breaking system etc. 8. Differentiate between CISC and RISC CISC is a Complex Instruction Set Computer. It is a computer that can address a large number of instructions. In the early 1980s, computer designers recommended that computers should use fewer instructions with simple constructs so that they can be executed much faster within the CPU without having to use memory. Such computers are classified as Reduced Instruction Set Computer or RISC. The following points differentiate a CISC from a RISC – CISC RISC Larger set of instructions. Easy to program Smaller set of Instructions. Difficult to program. Simpler design of compiler, considering larger Complex design of compiler. set of instructions. Many addressing modes causing complex Few addressing modes, fix instruction instruction formats. format. Instruction length is variable. Instruction length varies.  Higher clock cycles per second. Low clock cycle per second. Emphasis is on hardware. Emphasis is on software. Control unit implements large instruction set Each instruction is to be executed by using micro-program unit. hardware. Slower execution, as instructions are to be read Faster execution, as each instruction is to be from memory and decoded by the decoder unit. executed by hardware. Pipelining is not possible. Pipelining of instructions is possible, considering single clock cycle. 9. Architecture of PIC Microcontroller: The architecture of Peripheral Interface Controller comprises of central processing unit (CPU), I/O ports, A/D converter, memory organization, timers/counters, serial communication, interrupts, oscillator and CCP module that are discussed in detailed below. Central Processing Unit (CPU) PIC microcontroller’s CPU is not different like other microcontroller CPU, which includes the ALU, controller unit, the memory unit, and accumulator. ALU is mainly used for arithmetic and logical operations. The memory unit is used to store the commands after processing. The control unit is used to control the internal & external peripherals, and the accumulator is used to store the final results and further process. Memory Organization The memory module in the PIC microcontroller architecture consists of Random Access Memory, Read Only Memory and STACK. RAM (Random Access Memory) RAM is used to store the information temporarily in its registers. It is categorized into two banks, each bank has so many registers. The RAM registers are categorized into two types, namely SFR (Special Function Registers) and GPR (General Purpose Registers). Special Function Registers As the name implies, SFRs are used only for special purposes. These registers will work based on the function assigned to them, and these registers cannot work as a normal register. For instance, if you cannot use the STATUS register for storing the information, SFRs are used for viewing the status of the program. So, a consumer cannot change the SFR’s function; the function is given by the retailer at the time of built-up. Memory Organization The memory organization of Peripheral Interface Controller includes the following  Read Only Memory (ROM)  Electrically Erasable Programmable Read Only Memory (EEPROM)  Flash Memory  Stack  Figure: Architecture of PIC Microcontroller Memory Organization I/O Ports The PIC microcontroller consists of 5-ports, namely Port A, Port B, Port C, Port D and Port E. BUS BUS is used to transfer & receive the data from one peripheral to another. It is categorized into two types like data bus and address.Data Bus is used to transfer or receive the data. BUS The address bus is used to transfer the memory address from the peripherals to the central processing unit. Input/Output pins are used to interface the exterior peripherals; both the UART & USART are serial communication protocols, used to interface with serial devices such as GPS, GSM, IR, Bluetooth, etc. A/D Converters A/D converter is used to convert analog voltage values to digital voltage values. An A/D module in Peripheral Interface Controller comprises of 5-inputs for 28-pin devices & 8-inputs for 40-pin devices. The operation of the A/D converter is controlled by special registers like ADCON0 & ADCON1. The upper and lower bits of the converter are stored in registers like ADRESH and ADRESL. In this process, it needs 5V of an analog reference voltage. Analog to Digital converter Timers/ Counters PIC microcontroller has four-timer/counters wherein the one 8-bit timer and the remaining timers have the choice to select 8 or 16-bit mode. Timers are used for generating accuracy actions, for example, creating specific time delays between two operations. Interrupts PIC microcontroller consists of 20 internal & 3-external interrupt sources which are allied with different peripherals like USART, ADC, Timers, and so on. Serial Communication Serial communication is the method for transferring one-bit data at a time sequentially over a communication channel. Figure: Serial Communication using MAX 232 (i) USART The term USART stands for “Universal synchronous and Asynchronous Receiver” and Tx which is a serial communication for two protocols. USART is used for transmitting & receiving the data bit by bit over a single wire with respect to CLK pulses. The Peripheral Interface Controller consists of two pins TXD & RXD. These pins are used for transmitting & receiving the data serially. (ii) SPI Protocol The term SPI (Serial Peripheral Interface) is used to send information between PIC microcontroller and other peripherals like sensors, SD cards, and shift registers. This microcontroller supports 3-wire SPI communications between two devices on a common CLK source. The data rate of this protocol is more than that of the USART. (iii) I2C Protocol The term I2C stands for “Inter-Integrated Circuit”, and it is a serial protocol, used to connect low- speed devices like EEPROMS, A/D converters, microcontrollers, etc. PIC microcontroller supports this communication between two devices which can work as both Master & Slave device. Oscillators Oscillators are used for timing generation. This microcontroller comprises of external oscillators such as crystal oscillators or RC oscillators. Where the crystal oscillator is associated with the two pins of the oscillator. The capacitor value is connected to each pin that chooses the operation mode of the oscillator. These modes are the high-speed mode, crystal mode, and the low-power mode. In the case of RC oscillators, the resistor value and capacitor decide the CLK frequency and the clock frequency range from 30 KHz to 4 MHz. CCP Module The term CCP stands for “capture/compare/PWM” where it works in 3-modes such as compare mode, capture mode, and PWM mode. Capture Mode This mode captures the signal arrival time, or in other words, when the pin of this mode goes high, it captures the Timer1 value. Compare Mode Compare mode performances as an analog comparator. When the value of the timer1 reaches a certain reference value, then it produces an o/p. PWM Mode The PWM mode offers pulse width modulated o/p with a 10-bit resolution and programmable duty cycle. 10. Explain General-purpose registers and SFR registers General-purpose registers: General-purpose registers are used for storing temporary data and results created during operation. For example, if the program performs a counting (for example, counting products on the assembly line), it is necessary to have a register which stands for what we in everyday life call “sum”. Since the microcontroller is not creative at all, it is necessary to specify the address of some general purpose register by 1, after each product passes through a sensor, should be created. Therefore, the microcontroller can execute that program because it now knows what and where the sum which must be incremented is. Similar to this example, each program variable must be reassigned some of general-purpose register. SFR Registers: Special purpose registers are also Ram memory locations, but unlike general- purpose registers, their purpose is predetermined during manufacturing process and cannot be changed. Since their bits are physically connected to particular circuits on the chip (A/D converter, serial communication module, etc.), any change of their contents directly affects the operation of microcontroller or some of its circuits. For example, by changing TRISA register, the function of each port A pin can be changed in a way it acts as input or output. Another feature of these memory locations is that they have their names (registers and their bits), which considerably facilities program writing. Since high-level programming language can use the list of all registers with their exact addresses, it is enough to specify the register’s name in order to read or change its contents. 11. The key differences between microcontroller and microprocessor. Differences between microcontroller and microprocessor: 12. Explain Von Neumann and Harvard architecture with suitable diagram. Von Neumann Architecture The Von Neumann architecture was first proposed by a computer scientist John von Neumann. In this architecture, one data path or bus exists for both instruction and data. As a result, the CPU does one operation at a time. It either fetches an instruction from memory, or performs read/write operation on data. So an instruction fetch and a data operation cannot occur simultaneously, sharing a common bus. Von-Neumann architecture supports simple hardware. It allows the use of a single, sequential memory. Today's processing speeds vastly outpace memory access times, and we employ a very fast but small amount of memory (cache) local to the processor. Harvard Architecture The Harvard architecture offers separate storage and signal buses for instructions and data. This architecture has data storage entirely contained within the CPU, and there is no access to the instruction storage as data. Computers have separate memory areas for program instructions and data using internal data buses, allowing simultaneous access to both instructions and data. Programs needed to be loaded by an operator; the processor could not boot itself. In a Harvard architecture, there is no need to make the two memories share properties. 13. Differentiate between Von-Neumann Architecture vs Harvard Architecture The following points distinguish the Von Neumann Architecture from the Harvard Architecture. Von-Neumann Architecture Harvard Architecture Single memory to be shared by both code Separate memories for code and data. and data.  Processor needs to fetch code in a separate Single clock cycle is sufficient, as clock cycle and data in another clock cycle. separate buses are used to access code and So it requires two clock cycles. data. Higher speed, thus less time consuming. Slower in speed, thus more time- consuming. Simple in design. Complex in design. 14. Interrupt: An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention. Whenever an interrupt occurs, the controller completes the execution of the current instruction and starts the execution of an Interrupt Service Routine (ISR) or Interrupt Handler. ISR tells the processor or controller what to do when the interrupt occurs. The interrupts can be either hardware interrupts or software interrupts. Hardware Interrupt A hardware interrupt is an electronic alerting signal sent to the processor from an external device, like a disk controller or an external peripheral. For example, when we press a key on the keyboard or move the mouse, they trigger hardware interrupts which cause the processor to read the keystroke or mouse position. Software Interrupt A software interrupt is caused either by an exceptional condition or a special instruction in the instruction set which causes an interrupt when it is executed by the processor. For example, if the processor's arithmetic logic unit runs a command to divide a number by zero, to cause a divide-by- zero exception, thus causing the computer to abandon the calculation or display an error message. Software interrupt instructions work similar to subroutine calls. What is Polling? The state of continuous monitoring is known as polling. The microcontroller keeps checking the status of other devices; and while doing so, it does no other operation and consumes all its processing time for monitoring. This problem can be addressed by using interrupts. In the interrupt method, the controller responds only when an interruption occurs. Thus, the controller is not required to regularly monitor the status (flags, signals etc.) of interfaced and inbuilt devices. Interrupts v/s Polling Here is an analogy that differentiates an interrupt from polling − Interrupt Polling An interrupt is like a shopkeeper. If one The polling method is like a salesperson. The needs a service or product, he goes to him salesman goes from door to door while requesting and apprises him of his needs. In case of to buy a product or service. Similarly, the controller interrupts, when the flags or signals are keeps monitoring the flags or signals one by one for received, they notify the controller that they all devices and provides service to whichever need to be serviced. component that needs its service. Interrupt Service Routine For every interrupt, there must be an interrupt service routine (ISR), or interrupt handler. When an interrupt occurs, the microcontroller runs the interrupt service routine. For every interrupt, there is a fixed location in memory that holds the address of its interrupt service routine, ISR. The table of memory locations set aside to hold the addresses of ISRs is called as the Interrupt Vector Table. 15. Arduino: Arduino is an open-source electronics platform based on easy-to-use hardware and software. It's popular for both beginners and experts in electronics and programming. The Arduino boards read inputs (like light on a sensor or a button press) and turn them into outputs (like turning on an LED or activating a motor). Key elements of Arduino include:  Arduino Boards: Hardware components, such as the Arduino Uno, Nano, and Mega, which contain a microcontroller.  Arduino IDE: The Integrated Development Environment (IDE) where you write and upload code to the Arduino board.  Shields: Add-on boards that can be plugged into the Arduino to extend its capabilities (e.g., Wi-Fi shields, motor shields).  Sensors and Actuators: Arduino can interface with a wide range of sensors (temperature, light, proximity) and actuators (motors, LEDs). For teaching microcontrollers, Arduino is especially useful because of its simplicity and vast support community. 16. Arduino Boards Overview: Arduino boards are open-source microcontroller platforms designed to make it easier to create interactive projects. They come in various models, each tailored to different project requirements. The most common Arduino boards include:  Arduino Uno: A popular model for beginners, based on the ATmega328 microcontroller.  Arduino Nano: A smaller, compact version of the Uno, suitable for space-constrained projects.  Arduino Mega: For projects requiring more input/output pins and memory, based on the ATmega2560 microcontroller.  Arduino Leonardo: Features native USB communication, making it ideal for projects like custom keyboards or game controllers.  Arduino Due: Based on a 32-bit ARM microcontroller, offering more power for complex applications. 17. Arduino Advantages and Disadvantages: Advantages of Arduino Boards 1. Beginner-Friendly: Arduino is known for its simplicity. The hardware and software are easy to understand, making it accessible for beginners with little to no experience in electronics or programming. 2. Open-Source: Both the hardware and software are open-source, meaning users can modify or build upon the original designs. This fosters innovation and community contributions. 3. Wide Range of Applications: Arduino boards can be used in a variety of projects, from simple LED control to advanced robotics. It's versatile enough for prototyping, home automation, IoT projects, and more. 4. Large Community and Support: With a massive global user base, there are numerous tutorials, forums, and resources available online, making troubleshooting and learning much easier. 5. Extensive Libraries: The Arduino software (IDE) includes a wide range of libraries for interfacing with different sensors, motors, displays, and other components, simplifying code development. 6. Affordable: Arduino boards are relatively inexpensive, especially compared to other microcontroller platforms, which makes it affordable for hobbyists and students. 7. Cross-Platform: The Arduino IDE runs on Windows, macOS, and Linux, offering flexibility for developers who use different operating systems. 8. Rapid Prototyping: The simple setup and programming environment allow for quick prototyping of electronic projects, making it ideal for fast iterations and testing. Disadvantages of Arduino Boards 1. Limited Processing Power: Most Arduino boards, especially the Uno and Nano, are based on 8- bit microcontrollers with limited processing speed and memory, making them unsuitable for very complex or performance-intensive tasks. 2. Power Consumption: Arduino boards are not as power-efficient as other microcontroller platforms, such as the ESP32 or STM32, especially when used in battery-operated projects. 3. Limited Features for Advanced Users: While Arduino is great for beginners, advanced users might find its abstraction layer too limiting. The platform doesn't offer the fine-grained control needed for more specialized applications (e.g., real-time operating systems). 4. Basic IDE: The Arduino IDE is simple and functional but lacks some of the advanced features of modern integrated development environments (IDEs), such as advanced debugging, code refactoring tools, or integrated simulation. 5. Relatively Large Size: Compared to other microcontroller platforms, such as ARM-based boards (like the STM32) or ESP8266/ESP32, many Arduino boards are relatively large, which can be a limitation in space-constrained projects. 6. No Native Support for Complex Communication Protocols: Although shields are available, Arduino boards do not natively support advanced communication protocols like Wi-Fi, Bluetooth, or cellular without additional modules, making it slightly less integrated for IoT projects out of the box. 18. 8051 Microcontroller: The 8051 microcontroller is one of the most well-known and widely used microcontrollers, originally developed by Intel in 1980. It became popular due to its simplicity and versatility, and many companies still manufacture 8051-compatible microcontrollers. The 8051 architecture is used in embedded systems, industrial control systems, and consumer electronics. Key Features of the 8051 Microcontroller 1. 8-bit Microcontroller: The 8051 is an 8-bit microcontroller, meaning that the CPU can process 8 bits of data in a single operation. 2. Harvard Architecture: It uses the Harvard architecture, where the program memory (ROM) and data memory (RAM) are separate, allowing simultaneous access to both. 3. Clock Speed: Typical 8051 microcontrollers run at 12 MHz, but higher speeds can be achieved in modern variants. 4. Memory: o On-chip ROM: 8051 typically has 4 KB of ROM, which is used to store the program code. o On-chip RAM: The original 8051 has 128 bytes of RAM, with some variants having more. o External memory: It supports up to 64 KB of external program memory and 64 KB of external data memory. 5. I/O Ports: It has 4 I/O ports, each 8 bits wide, providing 32 general-purpose I/O pins for connecting to external devices. 6. Timers and Counters: The 8051 has two 16-bit timers/counters, which can be used for timing operations or counting external events. 7. Interrupt System: It features 5 interrupt sources, including two external interrupts, two timer interrupts, and a serial port interrupt, allowing the processor to respond quickly to external and internal events. 8. Serial Communication: The 8051 has a UART (Universal Asynchronous Receiver/Transmitter) for serial communication, making it easier to interface with serial devices like modems or other microcontrollers. 9. Power Saving Modes: The 8051 can operate in Idle and Power-down modes to save power, which is important in battery-powered applications. Advantages of the 8051 Microcontroller 1. Simplicity: The 8051 is a simple and easy-to-learn microcontroller, making it a popular choice for beginners. 2. Wide Availability: Many manufacturers produce 8051 variants, which makes it widely available and affordable. 3. Strong Community Support: Due to its popularity, there is a large amount of documentation, tutorials, and libraries available for working with the 8051. 4. Real-Time Applications: With its interrupt-driven capabilities, the 8051 is ideal for real-time applications like industrial control systems. 5. Stable Architecture: The 8051 has been around for decades, and its proven stability makes it a reliable choice for embedded systems. Disadvantages of the 8051 Microcontroller 1. Limited Processing Power: Being an 8-bit microcontroller with a modest clock speed, the 8051 is not suitable for complex or computationally demanding tasks. 2. Low Memory: The original 8051 has limited on-chip memory (4 KB ROM, 128 bytes RAM), which can restrict its use in applications that require large program sizes or data storage. 3. Lack of Modern Features: Compared to modern microcontrollers (like ARM Cortex-M or ESP32), the 8051 lacks advanced features such as higher clock speeds, better power efficiency, and integrated peripherals like Wi-Fi or Bluetooth. 4. External Components: For more extensive programs or data storage, external memory is required, increasing the complexity and size of the system. Applications of 8051 Microcontroller 1. Embedded Systems: Widely used in embedded applications such as remote controls, washing machines, and microwave ovens. 2. Industrial Automation: Used in industrial machines and process control systems due to its real- time processing capabilities. 3. Consumer Electronics: Found in devices like printers, keyboards, and security systems. 4. Automotive Systems: Deployed in various automotive control applications such as dashboard displays and engine management systems. 19. How to Program a Microcontroller: Programming a microcontroller involves several key steps, from selecting the microcontroller to writing code, compiling it, and finally uploading it to the microcontroller. Here's a step-by-step procedure to program a microcontroller: 1. Choose a microcontroller: Select one that fits your project requirements (e.g., Arduino, PIC, STM32). 2. Set up the development environment: o Install the appropriate Integrated Development Environment (IDE) o Install necessary drivers and toolchains 3. Learn the basics of the programming language: o Most microcontrollers use C or C++ o Some platforms like Arduino have their own simplified language 4. Understand the microcontroller's architecture: o Study the datasheet o Learn about registers, interrupts, and peripherals 5. Write your program: o Start with simple tasks like blinking an LED o Gradually build up to more complex functionality 6. Compile and upload: o Compile your code in the IDE o Upload it to the microcontroller using a programmer or bootloader 7. Test and debug: o Use debugging tools to identify and fix issues o Iterate on your code as needed ------x-----