Double buffer technique in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare two buffers for double buffering.

Embedded C

char buffer1[[1]];

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A128

B1024

C256

D512

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a buffer size too small to hold data.

The buffer size is set to 512 bytes to hold enough data for the double buffer.

2fill in blank

medium

Complete the code to switch the active buffer pointer.

Embedded C

activeBuffer = (activeBuffer == buffer1) ? buffer2 : [1];

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Abuffer1

Bbuffer0

Cbuffer3

Dbuffer4

Attempts:

3 left

💡 Hint

Common Mistakes

Using a buffer name that does not exist.

The active buffer switches back to buffer1 if it was buffer2, enabling double buffering.

3fill in blank

hard

Fix the error in the buffer swap function to correctly toggle buffers.

Embedded C

void swapBuffers() {
    if (currentBuffer == buffer1) {
        currentBuffer = [1];
    } else {
        currentBuffer = buffer1;
    }
}

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Abuffer1

Bbuffer3

Cbuffer2

Dbuffer0

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the same buffer again causing no toggle.

The function toggles currentBuffer between buffer1 and buffer2 for double buffering.

4fill in blank

hard

Fill both blanks to complete the double buffer initialization and usage.

Embedded C

char [1][512];
char [2][512];
char *activeBuffer = buffer1;

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Abuffer1

Bbuffer2

Cbuffer3

Dbuffer4

Attempts:

3 left

💡 Hint

Common Mistakes

Using buffer names that do not match the pointer initialization.

Two buffers named buffer1 and buffer2 are declared for double buffering.

5fill in blank

hard

Fill all three blanks to complete the double buffer data copy and swap logic.

Embedded C

void updateDisplay() {
    memcpy([1], [2], 512);
    [3] = ([3] == buffer1) ? buffer2 : buffer1;
}

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

AactiveBuffer

BinactiveBuffer

Cbuffer1

Dbuffer2

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the wrong buffer pointer or copying in the wrong direction.

Data is copied from inactiveBuffer to activeBuffer, then activeBuffer pointer toggles between buffer1 and buffer2.