Why DMA is needed in Embedded C - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a DMA transfer.

Embedded C

DMA_StartTransfer([1]);

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Adata

Bbuffer

Clength

Daddress

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the length instead of the data buffer.

Using the address variable which is not defined here.

The function DMA_StartTransfer needs the data buffer to begin the transfer.

2fill in blank

medium

Complete the code to check if DMA transfer is complete.

Embedded C

if (DMA_Status() == [1]) {
    // Transfer done
}

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ADMA_DONE

BDMA_BUSY

CDMA_ERROR

DDMA_IDLE

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for DMA_BUSY instead of DMA_DONE.

Using DMA_ERROR which means a problem occurred.

The status DMA_DONE indicates the DMA transfer has finished.

3fill in blank

hard

Fix the error in the DMA initialization code.

Embedded C

DMA_Init([1]);
DMA_StartTransfer(buffer, size);

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Asize

Bbuffer

Cconfig

Daddress

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the data buffer to DMA_Init instead of config.

Passing size or address which are not config structures.

The DMA_Init function requires a configuration structure, not the buffer or size.

4fill in blank

hard

Fill both blanks to create a DMA transfer that moves data from memory to peripheral.

Embedded C

DMA_SetSource([1]);
DMA_SetDestination([2]);

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Amemory_address

Bperipheral_address

Cbuffer

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping source and destination addresses.

Using buffer or size instead of addresses.

The source is the memory address and the destination is the peripheral address for this transfer.

5fill in blank

hard

Fill all three blanks to configure DMA with correct parameters.

Embedded C

DMA_Config config = {
    .source = [1],
    .destination = [2],
    .length = [3]
};

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Amemory_addr

Bperipheral_addr

Ctransfer_size

Dbuffer

Attempts:

3 left

💡 Hint

Common Mistakes

Using buffer instead of addresses.

Mixing up source and destination.

The DMA config needs source and destination addresses and the transfer size.