(SEM VI) THEORY EXAMINATION 2024-25 EMBEDDED SYSTEM

BOE062 – EMBEDDED SYSTEM

Section-Wise Solved Answers (2024–25)

SECTION A

Attempt all questions in brief (2 × 7 = 14 marks)

(a) Explain real-time scheduling in embedded systems.

Real-time scheduling is the method of deciding the execution order of tasks in an embedded system where timing constraints are critical. Each task must be completed within a specific deadline. Scheduling ensures that high-priority or time-critical tasks get CPU access before less important ones. Common scheduling techniques include rate-monotonic scheduling and earliest deadline first scheduling.

(b) Name the different components of embedded system hardware.

Embedded system hardware consists of a microcontroller or microprocessor, memory (RAM, ROM, Flash), input/output devices, sensors, actuators, communication interfaces, power supply, and clock circuitry. These components work together to perform dedicated functions.

(c) Define CAN Bus.

CAN (Controller Area Network) Bus is a serial communication protocol used mainly in automotive and industrial embedded systems. It allows multiple electronic control units to communicate with each other without a central controller, providing high reliability and real-time performance.

(d) Elaborate data flow graph in embedded firmware development environment.

A data flow graph (DFG) represents the flow of data between different processing blocks in an embedded system. Nodes represent operations or processes, and edges show data transfer. It helps designers visualize data dependencies, optimize performance, and efficiently allocate hardware or software resources.

(e) Discuss the functions of RTOS.

A Real-Time Operating System (RTOS) manages task scheduling, interrupt handling, memory management, inter-task communication, and synchronization. Its main function is to ensure predictable timing behavior so that real-time deadlines are always met.

(f) Mention the different states of a thread.

A thread can exist in different states such as new, ready, running, blocked/waiting, and terminated. These states describe the lifecycle of a thread during execution in an embedded system.

(g) Mention the design issues of embedded system application development.

Major design issues include real-time constraints, power consumption, limited memory, hardware-software integration, reliability, scalability, and security. Proper design must balance performance with cost and resource limitations.

SECTION B

Attempt any three (7 × 3 = 21 marks)

(a) Discuss watchdog timer.

A watchdog timer is a hardware or software timer used to detect and recover from system malfunctions. If the embedded system fails to reset the watchdog within a specified time, the timer triggers a system reset. This improves system reliability, especially in safety-critical applications.

(b) Discuss I/O device ports and serial bus communication protocols.

I/O device ports provide an interface between the processor and external devices like sensors, displays, and switches. Serial bus communication protocols such as UART, SPI, I²C, and CAN enable data transfer between embedded components using fewer wires, reducing complexity and cost.

(c) Explain the different phases of EDLC.

The Embedded Development Life Cycle (EDLC) consists of requirement analysis, system design, hardware and software co-design, implementation, testing and debugging, integration, and maintenance. Each phase ensures systematic development and reliable system performance.

(d) What are the functions of RTOS?

RTOS functions include task scheduling, context switching, interrupt handling, memory allocation, inter-process communication, and time management. These functions help in executing multiple tasks efficiently within strict timing constraints.

(e) Mention automotive applications in embedded system development.

Embedded systems are widely used in automotive applications such as engine control units, anti-lock braking systems, airbag control, infotainment systems, cruise control, and advanced driver assistance systems (ADAS).

 SECTION C

Attempt any one (7 × 1 = 7 marks)

(a) Elaborate the working and benefits of Direct Memory Access (DMA) in embedded systems.

DMA allows data transfer between memory and peripherals without CPU intervention. A DMA controller handles the data movement, freeing the CPU for other tasks. Benefits include faster data transfer, reduced CPU load, lower power consumption, and improved system performance.

(b) Define in-circuit emulator with benefits and industrial applications. Differentiate between in-circuit emulator and chip debugging.

An in-circuit emulator (ICE) is a debugging tool that replaces the target microcontroller and provides full control and monitoring of system operation.
ICE offers real-time debugging, full visibility of registers and memory, and accurate timing analysis.
Chip debugging uses on-chip debugging features and is less expensive but offers limited control compared to ICE.