PDM SDMA Driver

Typical use case

More...

Overview

The SDMA multi fifo script support transfer data between multi peripheral fifos and memory, a typical user case is that receiving multi PDM channel data and put it into memory as

| channel 0 | channel 1 | channel 2 | channel 3 | channel 4 | ......... |

Multi fifo script is target to implement above feature, it can supports 1.configurable fifo watermark range from 1~(2^12-1), it is a value of fifo_watermark * channel_numbers 2.configurable fifo numbers, support up to 15 continuous fifos 3.configurable fifo address offset, support address offset up to 64

/* load sdma script */
SDMA_LoadScript()
/* pdm multi channel configurations */
PDM_SetChannelConfigSDMA()
PDM_SetChannelConfigSDMA()
PDM_SetChannelConfigSDMA()
PDM_SetChannelConfigSDMA()
....

PDM_TransferReceiveSDMA

Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/pdm/pdm_sai_sdma

Data Structures
struct	_pdm_sdma_handle
	PDM DMA transfer handle, users should not touch the content of the handle. More...

Typedefs
typedef void(*	pdm_sdma_callback_t )(PDM_Type *base, pdm_sdma_handle_t *handle, status_t status, void *userData)
	PDM eDMA transfer callback function for finish and error.

Driver version
#define	FSL_PDM_SDMA_DRIVER_VERSION   (MAKE_VERSION(2, 7, 0))
	Version 2.7.0.

eDMA Transactional
void	PDM_TransferCreateHandleSDMA (PDM_Type *base, pdm_sdma_handle_t *handle, pdm_sdma_callback_t callback, void *userData, sdma_handle_t *dmaHandle, uint32_t eventSource)
	Initializes the PDM eDMA handle. More...
status_t	PDM_TransferReceiveSDMA (PDM_Type *base, pdm_sdma_handle_t *handle, pdm_transfer_t *xfer)
	Performs a non-blocking PDM receive using eDMA. More...
void	PDM_TransferAbortReceiveSDMA (PDM_Type *base, pdm_sdma_handle_t *handle)
	Aborts a PDM receive using eDMA. More...
void	PDM_SetChannelConfigSDMA (PDM_Type *base, pdm_sdma_handle_t *handle, uint32_t channel, const pdm_channel_config_t *config)
	PDM channel configurations. More...
void	PDM_TransferTerminateReceiveSDMA (PDM_Type *base, pdm_sdma_handle_t *handle)
	Terminate all the PDM sdma receive transfer. More...

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Data Structure Documentation

struct _pdm_sdma_handle

Data Fields
sdma_handle_t *	dmaHandle
	DMA handler for PDM send.
uint8_t	nbytes
	eDMA minor byte transfer count initially configured. More...
uint8_t	fifoWidth
	fifo width
uint8_t	endChannel
	The last enabled channel.
uint8_t	channelNums
	total channel numbers
uint32_t	count
	The transfer data count in a DMA request.
uint32_t	state
	Internal state for PDM eDMA transfer.
uint32_t	eventSource
	PDM event source number.
pdm_sdma_callback_t	callback
	Callback for users while transfer finish or error occurs.
void *	userData
	User callback parameter.
sdma_buffer_descriptor_t	bdPool [PDM_XFER_QUEUE_SIZE]
	BD pool for SDMA transfer. More...
pdm_transfer_t	pdmQueue [PDM_XFER_QUEUE_SIZE]
	Transfer queue storing queued transfer. More...
size_t	transferSize [PDM_XFER_QUEUE_SIZE]
	Data bytes need to transfer.
volatile uint8_t	queueUser
	Index for user to queue transfer. More...
volatile uint8_t	queueDriver
	Index for driver to get the transfer data and size.

Field Documentation

uint8_t _pdm_sdma_handle::nbytes

sdma_buffer_descriptor_t _pdm_sdma_handle::bdPool[PDM_XFER_QUEUE_SIZE]

pdm_transfer_t _pdm_sdma_handle::pdmQueue[PDM_XFER_QUEUE_SIZE]

volatile uint8_t _pdm_sdma_handle::queueUser

Function Documentation

void PDM_TransferCreateHandleSDMA	(	PDM_Type *	base,
		pdm_sdma_handle_t *	handle,
		pdm_sdma_callback_t	callback,
		void *	userData,
		sdma_handle_t *	dmaHandle,
		uint32_t	eventSource
	)

This function initializes the PDM DMA handle, which can be used for other PDM master transactional APIs. Usually, for a specified PDM instance, call this API once to get the initialized handle.

Parameters

base	PDM base pointer.
handle	PDM eDMA handle pointer.
callback	Pointer to user callback function.
userData	User parameter passed to the callback function.
dmaHandle	eDMA handle pointer, this handle shall be static allocated by users.
eventSource	PDM event source number.

status_t PDM_TransferReceiveSDMA	(	PDM_Type *	base,
		pdm_sdma_handle_t *	handle,
		pdm_transfer_t *	xfer
	)

Note

This interface returns immediately after the transfer initiates. Call the PDM_GetReceiveRemainingBytes to poll the transfer status and check whether the PDM transfer is finished.

Parameters

base	PDM base pointer
handle	PDM eDMA handle pointer.
xfer	Pointer to DMA transfer structure.

Return values

kStatus_Success	Start a PDM eDMA receive successfully.
kStatus_InvalidArgument	The input argument is invalid.
kStatus_RxBusy	PDM is busy receiving data.

void PDM_TransferAbortReceiveSDMA	(	PDM_Type *	base,
		pdm_sdma_handle_t *	handle
	)

Parameters

base	PDM base pointer
handle	PDM eDMA handle pointer.

void PDM_SetChannelConfigSDMA	(	PDM_Type *	base,
		pdm_sdma_handle_t *	handle,
		uint32_t	channel,
		const pdm_channel_config_t *	config
	)

Parameters

base	PDM base pointer.
handle	PDM eDMA handle pointer.
channel	channel number.
config	channel configurations.

void PDM_TransferTerminateReceiveSDMA	(	PDM_Type *	base,
		pdm_sdma_handle_t *	handle
	)

Parameters

base	PDM base pointer.
handle	PDM SDMA handle pointer.