DMA controller concept in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable the DMA controller.

Embedded C

DMA->[1] |= DMA_ENABLE;

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ACONFIG

BCTRL

CSTATUS

DINTERRUPT

Attempts:

3 left

💡 Hint

Common Mistakes

Using STATUS register instead of CONFIG.

Trying to enable DMA in INTERRUPT register.

The DMA controller is enabled by setting the enable bit in the CONFIG register.

2fill in blank

medium

Complete the code to set the source address for DMA transfer.

Embedded C

DMA->SRC_ADDR = [1];

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A0x40000000

BDMA_ENABLE

C0x20000000

D0x00000000

Attempts:

3 left

💡 Hint

Common Mistakes

Using DMA_ENABLE instead of an address.

Using zero address which is usually invalid.

The source address must be a valid memory address where data is read from.

3fill in blank

hard

Fix the error in the code to start the DMA transfer.

Embedded C

DMA->[1] = 1; // Start transfer

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ACTRL

BCONFIG

CSTATUS

DSRC_ADDR

Attempts:

3 left

💡 Hint

Common Mistakes

Writing to STATUS register which is read-only.

Writing to SRC_ADDR which sets address, not start.

The CTRL register is used to start or stop the DMA transfer by writing 1 to the start bit.

4fill in blank

hard

Fill both blanks to configure the DMA transfer size and direction.

Embedded C

DMA->[1] = 256; // Transfer size
DMA->[2] = [2]_MEM_TO_PERIPH;

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ASIZE

BDIR

CCTRL

DCONFIG

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing CTRL with SIZE or DIR registers.

Setting direction in CONFIG register incorrectly.

SIZE register sets the number of bytes to transfer. DIR register sets the direction of transfer.

5fill in blank

hard

Fill all three blanks to create a DMA transfer descriptor with source, destination, and size.

Embedded C

dma_desc.src_addr = [1];
dma_desc.dst_addr = [2];
dma_desc.size = [3];

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A0x20001000

B0x40002000

C512

DDMA_ENABLE

Attempts:

3 left

💡 Hint

Common Mistakes

Using DMA_ENABLE as an address or size.

Mixing up source and destination addresses.

The source and destination addresses must be valid memory locations. Size is the number of bytes to transfer.