Generic Vector DMA layer

group nrf_vdma

Helper layer that provides the common functionality for Vector DMA (VDMA).

Defines

NRF_VDMA_BUFFER_SIZE_MASK

Maximum size of VDMA buffer.

NRF_VDMA_REDUCED_JOB_SIZE(count)

Macro for computing size of the array of reduced job structures.

Parameters:

  • count – [in] Number of jobs to be stored in reduced job list.

NRF_VDMA_JOB_ELEMENT(p_buffer, size, attribute)

Macro for defining an element of a job list.

Parameters:

  • p_buffer – [in] Pointer to the buffer.

  • size – [in] Size of the transfer.

  • attribute – [in] Attribute mask.

Returns:

Two words of the job descriptor.

NRF_VDMA_REDUCED_JOB_INIT_ELEMENT(p_buffer, size, attribute)

Macro for defining initial element of reduced job list.

Parameters:

  • p_buffer – [in] Job buffer.

  • size – [in] Size of the job buffer.

  • attribute – [in] Attributes of the job.

Returns:

Two words of the job descriptor.

NRFX_VDMA_PERIPH_JOB(addr, size)

Macro for defining a job for transfer engaging peripheral.

Parameters:

  • addr – [in] Starting address.

  • size – [in] Size of a DMA job.

Returns:

Two words which contains address, size and the descriptor byte.

Typedefs

typedef uint32_t nrf_vdma_job_reduced_t

Type describing VDMA job with fixed attributes and length.

Enums

enum nrf_vdma_attributes_t

VDMA attributes.

Note

Only one attribute can be set for the job.

Values:

enumerator NRF_VDMA_ATTRIBUTE_PLAIN_DATA

Data is not modified.

enumerator NRF_VDMA_ATTRIBUTE_BYTE_SWAP

Data bytes are swapped.

enumerator NRF_VDMA_ATTRIBUTE_JOB_LIST

Allows chaining of joblists.

enumerator NRF_VDMA_ATTRIBUTE_BUFFER_FILL

Insters zeros into sink data buffers. Sink job attribute only.

enumerator NRF_VDMA_ATTRIBUTE_FIXED_ATTR

Identical job attributes and sizes for all jobs in the list.

enumerator NRF_VDMA_ATTRIBUTE_CRC

CRC checksum is calculated on all data in the source list.

enumerator NRF_VDMA_ATTRIBUTE_STATIC_ADDR

Memory address is fixed for the entirety of the job.

enumerator NRF_VDMA_ATTRIBUTE_PLAIN_DATA_BUF_WRITE

Used to get better write performance when many short bursts are beiing sent.

enum nrf_vdma_ext_attribute_t

VDMA extended attributes.

Note

This attributes can be combined with each other and with standard attribute

Values:

enumerator NRF_VDMA_EXT_ATTRIBUTE_PERIPHERAL_MODE
enumerator NRF_VDMA_EXT_ATTRIBUTE_EVENT_ENABLE

Functions

__STATIC_INLINE void nrf_vdma_job_fill(nrf_vdma_job_t *p_job, void *p_buffer, size_t size, uint8_t attributes)

Function for filling the specified structure of the job with given job parameters.

Parameters:

  • p_job – [out] Pointer to the structure of the job to be filled.

  • p_buffer – [in] Job buffer.

  • size – [in] Size of the job buffer.

  • attributes – [in] Attributes of the job.

__STATIC_INLINE void nrf_vdma_job_reduced_init(nrf_vdma_job_reduced_t *p_job, void *p_buffer, size_t size, uint8_t attributes)

Function for initializing the specified structure of the job with fixed attributes.

First element of reduced job list occupies space for two elements.

Note

Use nrf_vdma_job_terminate() to terminate reduced job list.

Parameters:

  • p_job – [out] Pointer to the reduced structure of the job to be filled.

  • p_buffer – [in] Job buffer.

  • size – [in] Size of the job buffer.

  • attributes – [in] Additional attribute of the job.

__STATIC_INLINE void nrf_vdma_job_reduced_fill(nrf_vdma_job_reduced_t *p_job, void *p_buffer)

Function for filling the specified reduced structure of the job with given buffer pointer.

Parameters:

  • p_job – [out] Pointer to the reduced structure of the job to be filled.

  • p_buffer – [in] Job buffer.

__STATIC_INLINE void *nrf_vdma_job_buffer_get(nrf_vdma_job_t const *p_job)

Function for getting the pointer to the buffer associated with specified job.

Parameters:

  • p_job – [in] Pointer to the structure of the specified job.

Returns:

Pointer to the job buffer.

__STATIC_INLINE size_t nrf_vdma_job_size_get(nrf_vdma_job_t const *p_job)

Function for getting the size of the buffer associated with specified job.

Parameters:

  • p_job – [in] Pointer to the structure of the specified job.

Returns:

Size of the job buffer.

__STATIC_INLINE void nrf_vdma_job_terminate(nrf_vdma_job_t *p_job)

Function for terminating the specified job.

When VectorDMA encounters job that is terminated, processing of the job list stops.

Parameters:

  • p_job – [out] Pointer to the structure of the job to be terminated.

Function for linking the job with another job.

When VectorDMA encounters job that is linked to another job, execution of the linked job starts.

Parameters:

  • p_job – [out] Pointer to the structure of the job to become link.

  • p_job_linked – [in] Pointer to the structure of the job to be linked.

struct nrf_vdma_job_t
#include <nrf_vdma.h>

Structure describing VDMA job.

Public Members

uint8_t *p_buffer

Pointer to the VDMA job buffer.

uint32_t size

Size of the job buffer.

uint8_t attributes

Attributes of the job.