Explore key concepts of interrupts and timers in embedded systems with this quiz designed to assess your understanding of event-driven execution, timer operations, and related hardware mechanisms. Ideal for professionals and learners seeking to strengthen their grasp on embedded system timing and interrupt handling techniques.
Which of the following is most commonly used as an external interrupt source in embedded systems to detect a button press event?
Explanation: A GPIO pin is typically used to detect digital changes, such as a button press, which can trigger an external interrupt. An analog comparator is designed for comparing voltage levels, and while it can generate interrupts, it is less common for simple digital inputs like button presses. PWM output is used for generating variable signals and is not suited for detecting external events. I2C bus is a communication interface and does not inherently serve as a direct interrupt source for button events.
In an embedded system with multiple interrupt sources, what happens if two interrupts with different priority levels occur at the same time?
Explanation: Most embedded systems employ an interrupt priority mechanism, ensuring that the higher priority interrupt is handled first while the lower priority interrupt waits. Simultaneously servicing both interrupts is not feasible due to hardware limitations. Ignoring both interrupts would defeat their purpose, and servicing the lower priority first is not consistent with established interrupt handling strategies in embedded systems.
Which timer mode would be most appropriate for generating a precise one-time delay in an embedded application, such as turning off an LED after a specific period?
Explanation: One-shot mode allows a timer to generate a single event after a set interval, suitable for tasks like turning off an LED after a defined period. Continuous mode is intended for periodic events and would continue indefinitely. While capture and compare modes offer special features for input timing and output timing respectively, they are not designed solely for generating one-time delays the way one-shot mode is.
What is the primary purpose of an Interrupt Service Routine (ISR) in embedded systems, for example when handling a timer overflow?
Explanation: An ISR is designed to respond immediately to specific interrupt events, like a timer overflow, executing the relevant code as soon as the event occurs. Background polling is handled by the main program loop and not by ISRs. Hardware initialization usually takes place during system startup routines, and periodic resets are not the function of an ISR, but rather a result of watchdog mechanisms or deliberate system control.
How does the clock frequency supplied to a timer influence its timing resolution in an embedded system?
Explanation: A higher clock frequency means the timer ticks faster, allowing it to measure smaller increments of time, resulting in increased timing resolution. Lower frequencies have the opposite effect, reducing resolution. Clock frequency is a critical factor in timer accuracy, and it does not disable the timer. Saying clock frequency has no effect on resolution or disables the timer is incorrect.