State machine for protocol handling in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Embedded C

enum State { IDLE, RECEIVING, PROCESSING, [1] };

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ADONE

BWAITING

CERROR

DSENDING

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a state that does not represent sending data.

Using a state that is not part of the protocol flow.

The state SENDING is commonly used to represent the state where the protocol is sending data.

2fill in blank

medium

Complete the code to transition to the PROCESSING state when data is received.

Embedded C

if (event == DATA_RECEIVED) {
    current_state = [1];
}

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AIDLE

BPROCESSING

CSENDING

DRECEIVING

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the state to IDLE instead of PROCESSING.

Using RECEIVING which is the previous state.

When data is received, the protocol should move to the PROCESSING state to handle the data.

3fill in blank

hard

Fix the error in the state transition to IDLE after sending is done.

Embedded C

if (event == SEND_COMPLETE) {
    current_state = [1];
}

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AIDLE

BRECEIVING

CERROR

DPROCESSING

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the state to PROCESSING or RECEIVING incorrectly.

Using ERROR state without an error event.

After sending is complete, the protocol should return to the IDLE state to wait for new events.

4fill in blank

hard

Fill both blanks to complete the state machine switch-case for handling events.

Embedded C

switch (current_state) {
    case IDLE:
        if (event == START_RECEIVE) {
            current_state = [1];
        }
        break;
    case RECEIVING:
        if (event == DATA_RECEIVED) {
            current_state = [2];
        }
        break;
}

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ARECEIVING

BPROCESSING

CIDLE

DSENDING

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the states in the blanks.

Using IDLE or SENDING incorrectly in these transitions.

From IDLE, on START_RECEIVE, move to RECEIVING. From RECEIVING, on DATA_RECEIVED, move to PROCESSING.

5fill in blank

hard

Fill all three blanks to complete the dictionary-like state transition table.

Embedded C

State next_state(State current, Event event) {
    if (current == [1] && event == START_SEND) {
        return [2];
    } else if (current == [3] && event == SEND_COMPLETE) {
        return IDLE;
    }
    return current;
}

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APROCESSING

BIDLE

CSENDING

DRECEIVING

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the states for sending and idle.

Returning wrong states on events.

When in IDLE and START_SEND event occurs, move to SENDING. When in SENDING and SEND_COMPLETE event occurs, return to IDLE.