Why state machines are used in embedded in Embedded C - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the initial state of the state machine.

Embedded C

enum State { INIT, RUNNING, ERROR };
State currentState = [1];

Drag options to blanks, or click blank then click option'

ARUNNING

BINIT

CERROR

DSTOPPED

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a state that is not defined like STOPPED.

Starting directly in ERROR or RUNNING state.

The initial state is usually set to INIT to start the state machine properly.

2fill in blank

medium

Complete the code to transition from INIT to RUNNING state.

Embedded C

if (currentState == INIT) {
    currentState = [1];
}

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ARUNNING

BERROR

CINIT

DSTOPPED

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the state back to INIT causing a loop.

Using an undefined state like STOPPED.

After initialization, the state machine moves to the RUNNING state to perform its main tasks.

3fill in blank

hard

Fix the error in the switch statement to handle the ERROR state.

Embedded C

switch (currentState) {
    case INIT:
        // initialization code
        break;
    case RUNNING:
        // running code
        break;
    case [1]:
        // error handling code
        break;
    default:
        break;
}

Drag options to blanks, or click blank then click option'

ASTOPPED

BINIT

CRUNNING

DERROR

Attempts:

3 left

💡 Hint

Common Mistakes

Using a state that does not exist like STOPPED.

Repeating INIT or RUNNING in the error case.

The ERROR state must be handled explicitly in the switch to manage error conditions.

4fill in blank

hard

Fill both blanks to check if the state machine is in RUNNING state and then set it to ERROR.

Embedded C

if (currentState == [1]) {
    currentState = [2];
}

Drag options to blanks, or click blank then click option'

ARUNNING

BINIT

CERROR

DSTOPPED

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the states in condition and assignment.

Using undefined states like STOPPED.

This code checks if the machine is RUNNING and sets it to ERROR if a problem occurs.

5fill in blank

hard

Fill all three blanks to create a dictionary that maps states to their string names.

Embedded C

const char* stateNames[] = { [1], [2], [3] };

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A"INIT"

B"RUNNING"

C"ERROR"

D"STOPPED"

Attempts:

3 left

💡 Hint

Common Mistakes

Including undefined states like STOPPED.

Mixing the order of state names.

This array holds the string names for each state in order: INIT, RUNNING, ERROR.