I2C acknowledge and NACK behavior in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send an ACK after receiving a byte on I2C.

Embedded C

if (I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)) {
    uint8_t data = I2C_ReceiveData(I2C1);
    I2C_[1](I2C1, ENABLE);  // Send ACK
}

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ANACKConfig

BAcknowledgeConfig

CStopConfig

DStartConfig

Attempts:

3 left

💡 Hint

Common Mistakes

Using NACKConfig instead of AcknowledgeConfig

Confusing StopConfig with ACK control

The function AcknowledgeConfig enables sending an ACK after receiving a byte.

2fill in blank

medium

Complete the code to send a NACK after the last byte is received on I2C.

Embedded C

if (last_byte_received) {
    I2C_[1](I2C1, ENABLE);  // Send NACK
}

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AAcknowledgeConfig

BStopConfig

CNACKConfig

DStartConfig

Attempts:

3 left

💡 Hint

Common Mistakes

Using AcknowledgeConfig instead of NACKConfig

Forgetting to send NACK after last byte

To signal the end of data reception, NACKConfig is enabled to send a NACK.

3fill in blank

hard

Fix the error in the code to properly generate a NACK after receiving the last byte.

Embedded C

if (I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)) {
    if (last_byte) {
        I2C_AcknowledgeConfig(I2C1, [1]);  // Should send NACK
    }
    uint8_t data = I2C_ReceiveData(I2C1);
}

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ADISABLE

BENABLE

CTRUE

DFALSE

Attempts:

3 left

💡 Hint

Common Mistakes

Passing ENABLE instead of DISABLE

Not disabling acknowledge before last byte

To send a NACK, the acknowledge must be disabled by passing DISABLE.

4fill in blank

hard

Fill both blanks to correctly check for ACK and NACK events in I2C communication.

Embedded C

if (I2C_CheckEvent(I2C1, [1])) {
    // ACK received
}
else if (I2C_CheckEvent(I2C1, [2])) {
    // NACK received
}

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AI2C_EVENT_MASTER_BYTE_TRANSMITTED

BI2C_EVENT_MASTER_BYTE_RECEIVED

CI2C_EVENT_MASTER_NACK

DI2C_EVENT_MASTER_MODE_SELECT

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing transmit and receive events

Using wrong event constants

I2C_EVENT_MASTER_BYTE_RECEIVED indicates an ACK after byte reception, and I2C_EVENT_MASTER_NACK indicates a NACK event.

5fill in blank

hard

Fill all three blanks to implement sending a NACK and STOP condition after the last byte is received.

Embedded C

if (last_byte) {
    I2C_AcknowledgeConfig(I2C1, [1]);  // Send NACK
    I2C_GenerateSTOP(I2C1, [2]);          // Generate STOP
    while (!I2C_GetFlagStatus(I2C1, [3])) {}
}

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ADISABLE

BENABLE

CI2C_FLAG_STOPF

DI2C_FLAG_TXE

Attempts:

3 left

💡 Hint

Common Mistakes

Enabling acknowledge instead of disabling

Waiting for wrong flag

Not generating STOP condition

To send a NACK, acknowledge is disabled (DISABLE). The STOP condition is generated by enabling it (ENABLE). The code waits for the STOP flag (I2C_FLAG_STOPF) to confirm the STOP condition.