ADC interrupt-driven reading in Embedded C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main advantage of using ADC interrupt-driven reading over polling?

Interrupt-driven reading allows the CPU to perform other tasks and only respond when the ADC conversion is complete, improving efficiency and responsiveness.

beginner

In ADC interrupt-driven reading, what triggers the interrupt?

The ADC hardware triggers an interrupt when the analog-to-digital conversion is finished and the result is ready to be read.

intermediate

What is the typical role of the Interrupt Service Routine (ISR) in ADC interrupt-driven reading?

The ISR reads the ADC conversion result, processes or stores it, and clears the interrupt flag to prepare for the next conversion.

intermediate

Why is it important to clear the ADC interrupt flag inside the ISR?

Clearing the interrupt flag prevents the ISR from being called repeatedly for the same event and allows new ADC interrupts to be detected.

intermediate

How do you start a new ADC conversion in an interrupt-driven ADC reading system?

You typically start a new ADC conversion either at the end of the ISR or by a timer or event that triggers the ADC hardware to begin conversion again.

What happens when the ADC conversion completes in an interrupt-driven system?

A An interrupt is triggered to run the ISR

B The CPU stops all tasks

C The ADC conversion restarts automatically

D The system resets

When ADC conversion finishes, it triggers an interrupt to run the ISR where the result is handled.

Where should the ADC result be read in an interrupt-driven ADC system?

A In the main loop before starting conversion

B In a separate thread

C After system reset

D Inside the Interrupt Service Routine (ISR)

The ADC result is read inside the ISR to immediately process the conversion result.

Why is polling less efficient than interrupt-driven ADC reading?

A Polling is faster

B Polling wastes CPU time checking repeatedly

C Polling uses less power

D Polling requires no code

Polling wastes CPU cycles by constantly checking if conversion is done instead of reacting only when ready.

What must be done inside the ISR to allow future ADC interrupts?

A Reset the microcontroller

B Disable ADC

C Clear the ADC interrupt flag

D Start a new ADC conversion

Clearing the interrupt flag inside the ISR allows the system to detect the next ADC interrupt.

How can you trigger ADC conversions repeatedly in an interrupt-driven system?

A Start a new conversion at the end of the ISR or use a timer

B Only once at system start

C By polling continuously

D By resetting the CPU

Starting a new conversion inside the ISR or using a timer ensures continuous ADC readings.

Explain how ADC interrupt-driven reading works and why it is useful.

Think about how the CPU reacts only when ADC finishes.

Describe the key steps you must do inside the ADC ISR.

Focus on what happens right after ADC conversion completes.