5.1 State TWO applications of microcontrollers in commercial devices - NSC Electrical Technology Digital - Question 5 - 2020 - Paper 1

A = ROM (Read-Only Memory) B = RAM (Random Access Memory)

The CPU (Central Processing Unit) is responsible for interpreting and executing the instructions stored in the memory. It acts as the brain of the microcontroller, performing calculations and making logical decisions based on the program.

The input/output unit enables the microcontroller to interface with external devices. It facilitates communication with sensors, displays, and other peripherals, allowing the microcontroller to receive input signals and send output signals.

1. Integration: Microcontrollers combine multiple functions into a single chip, reducing the number of discrete components needed.
2. Cost-Effectiveness: Utilizing microcontrollers can lower production costs due to reduced material and assembly requirements.
3. Flexibility: Microcontrollers can be programmed for various tasks, making them more adaptable than traditional discrete components.

A CPU register is a small data storage location within the CPU used to hold data temporarily while it's being processed. Registers enable high-speed data access and manipulation, crucial for efficient CPU operation.

1. Program Counter (PC): Holds the address of the next instruction to be executed.
2. Memory Address Register (MAR): Contains the address of the memory location to be accessed.
3. Current Instruction Register (CIR): Stores the current instruction that is being executed.

The A/D (Analog-to-Digital) converter transforms an analog signal into a digital format that the CPU can interpret. This conversion is essential for microcontrollers to process real-world signals, such as temperature and light levels.

An A/D converter is used with microcontrollers to enable digital processing of analog signals. Since most sensors output analog data, the A/D converter allows the microcontroller to handle these signals efficiently, making it possible to automate and control various processes.

A = Data bus

The control bus carries control signals from the CPU to various components within the computer system, managing the timing and direction of data transfers. It coordinates the operations of the CPU, memory, and input/output devices.

The address bus transmits memory addresses from the CPU to other components. It specifies where data is being sent or received in memory, ensuring the correct addressing of storage locations.

SPI is characterized by:

1. Full Duplex Communication: It can send and receive data simultaneously.
2. Master-Slave Configuration: One device acts as the master controlling the communication, while one or more devices serve as slaves.
3. Separate Data Lines: Using different lines for data input and output streamlines the communication process.

The SPI serves to provide fast and efficient communication between microcontrollers and peripheral devices, facilitating data transfer with minimal latency.

1. Digital Signal Processors (DSPs): SPI is commonly used for communication between microcontrollers and DSPs for audio or signal processing tasks.
2. Shift Registers: It can interface with shift registers in applications needing to control multiple output devices.

For RS-485 communications:

• Logic '1': Typically around +200mV or greater.
• Logic '0': Typically around -200mV or less.

1. Point of Sale Terminals: Used for financial transactions.
2. PLC's (Programmable Logic Controllers): Widely used in automation systems.
3. Metering Instruments: For measuring and monitoring electrical consumption.

A = Sender/Transmitter B = Direction of data flow / data flow C = Receiver

Data is transferred through the device in the form of a continuous stream or block of data. Each bit is transmitted sequentially, and at the receiving end, these bits are counted and reconstructed into bytes. Synchronization via a common clock ensures that both the sender and receiver are aligned for accurate data communication.