DMA with UART for bulk transfer in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable DMA for UART transmission.

Embedded C

UART->CR3 |= [1];

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AUSART_CR3_DMAT

BUSART_CR3_DMAR

CUSART_CR3_TE

DUSART_CR3_RE

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing DMA transmit enable with DMA receive enable.

Setting transmit or receive enable bits instead of DMA bits.

To enable DMA for UART transmission, set the DMAT bit in the UART control register 3.

2fill in blank

medium

Complete the code to configure the DMA channel for UART transmission direction.

Embedded C

DMA_Channel->CCR |= [1];

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ADMA_CCR_TCIE

BDMA_CCR_DIR

CDMA_CCR_EN

DDMA_CCR_MINC

Attempts:

3 left

💡 Hint

Common Mistakes

Using the enable bit instead of direction bit.

Confusing memory increment with direction.

The DIR bit in DMA channel configuration register sets the data transfer direction from memory to peripheral for UART transmission.

3fill in blank

hard

Fix the error in setting the DMA buffer size for UART transmission.

Embedded C

DMA_Channel->CNDTR = [1];

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Astrlen(buffer)

Bsizeof(buffer)

CBUFFER_SIZE

Dsizeof(buffer) - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using strlen which works only for strings, not binary data.

Using sizeof on a pointer instead of the actual buffer size.

The buffer size should be set explicitly with a defined constant representing the number of bytes to transfer, such as BUFFER_SIZE.

4fill in blank

hard

Fill both blanks to correctly configure DMA memory increment and enable the channel.

Embedded C

DMA_Channel->CCR |= [1] | [2];

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ADMA_CCR_MINC

BDMA_CCR_DIR

CDMA_CCR_EN

DDMA_CCR_TCIE

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to enable the DMA channel.

Confusing direction bit with memory increment.

Memory increment (MINC) must be enabled to move through the buffer, and the DMA channel must be enabled (EN) to start the transfer.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps UART buffer indices to their values if the value is greater than zero.

Embedded C

uart_data = [1]: [2] for [3] in range(BUFFER_SIZE) if buffer[[3]] > 0

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Ai

Bbuffer[i]

Dbuffer

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable name for the loop index.

Confusing the key and value in the comprehension.

This comprehension creates a dictionary where keys are indices i and values are buffer[i] for all indices where the buffer value is positive.