What is the key difference between a microcontroller and a microprocessor?

A microcontroller runs faster than a microprocessor A microcontroller includes CPU, memory, and peripherals on one chip; a microprocessor is CPU only A microprocessor can run an operating system; a microcontroller cannot run any software A microcontroller only processes analog signals

An Arduino Uno has 32 KB of Flash memory and 2 KB of SRAM. What are these two types of memory used for?

Flash stores temporary sensor readings; SRAM stores the bootloader permanently Flash stores the program code (non-volatile); SRAM stores variables during execution (volatile) Both Flash and SRAM store code; Flash is faster SRAM is used for long-term data logging; Flash for network communication

A microcontroller GPIO pin is configured as an output and set HIGH (5 V). A 220 Ω resistor and an LED are connected in series to ground. Approximately what current flows through the LED?

Approximately 5 mA Approximately 19 mA Approximately 100 mA Approximately 1 mA

A PWM output on a microcontroller runs at 1 kHz with a 75% duty cycle driving a motor. What is the effective average voltage on a 5 V system?

1.25 V 5 V 3.75 V 2.5 V

Which communication protocol uses only 2 wires (SDA and SCL) and supports multiple devices on the same bus?

SPI UART I2C CAN bus

Why are interrupts preferred over polling when responding to a button press on a microcontroller?

Polling is faster but interrupts use less code Interrupts let the CPU do other work and respond immediately when the button is pressed, rather than repeatedly checking its state Interrupts require less power because the button controls the CPU clock Polling is only for analog sensors; interrupts only work for digital signals

What is the purpose of a watchdog timer in an embedded system?

It measures how long the program has been running to optimise power usage It resets the microcontroller if the program hangs and fails to reset the timer within a set period It prevents the clock speed from exceeding the rated maximum It monitors the watchdog sensor for temperature overload

SPI (Serial Peripheral Interface) is often used for communicating with SD cards and displays rather than I2C. Why?

SPI uses less power, making it better for battery-powered displays SPI is significantly faster than I2C, achieving tens of Mbps because it uses separate MOSI and MISO lines and no addressing overhead SPI supports more devices on a single bus than I2C SPI is the only protocol that works at 3.3 V

A microcontroller's 12-bit ADC reads a temperature sensor output of 2.0 V on a 0–3.3 V reference. What is the digital reading?

2048 2482 3300 1240

What is the role of a Real-Time Operating System (RTOS) in an embedded system?

It provides a user graphical interface for embedded systems It schedules multiple tasks with guaranteed timing, ensuring critical tasks run within their deadlines It replaces Flash memory with faster virtual memory It automatically compiles and uploads code to the microcontroller

The Arduino Uno uses the ATmega328P running at 16 MHz. Approximately how many simple instructions can it execute per second?

160,000 instructions per second 16,000 instructions per second 16 million instructions per second 160 billion instructions per second

In an embedded system controlling a greenhouse, a sensor reads soil moisture every 10 seconds using I2C, and a pump is controlled via a relay on a GPIO pin. Which architecture is most appropriate?

A hard real-time RTOS with three preemptive tasks running at 1 kHz A full Linux operating system for maximum flexibility A simple superloop (main loop) with timer-driven reads, without an RTOS A multi-core microprocessor with distributed memory