Pdm_edma

Overview

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

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

Driver version
#define	FSL_PDM_EDMA_DRIVER_VERSION   (MAKE_VERSION(2, 0, 0))
	Version 2.0.0.

PDM eDMA Transactional
void	PDM_TransferInstallEDMATCDMemory (pdm_edma_handle_t *handle, void *tcdAddr, size_t tcdNum)
	Install EDMA descriptor memory. More...
void	PDM_TransferCreateHandleEDMA (PDM_Type *base, pdm_edma_handle_t *handle, pdm_edma_callback_t callback, void *userData, edma_handle_t *dmaHandle)
	Initializes the PDM Rx eDMA handle. More...
void	PDM_TransferSetChannelConfigEDMA (PDM_Type *base, pdm_edma_handle_t *handle, uint32_t channel, const pdm_channel_config_t *config)
	Configures the PDM channel. More...
status_t	PDM_TransferReceiveEDMA (PDM_Type *base, pdm_edma_handle_t *handle, pdm_edma_transfer_t *xfer)
	Performs a non-blocking PDM receive using eDMA. More...
void	PDM_TransferTerminateReceiveEDMA (PDM_Type *base, pdm_edma_handle_t *handle)
	Terminate all PDM receive. More...
void	PDM_TransferAbortReceiveEDMA (PDM_Type *base, pdm_edma_handle_t *handle)
	Aborts a PDM receive using eDMA. More...
status_t	PDM_TransferGetReceiveCountEDMA (PDM_Type *base, pdm_edma_handle_t *handle, size_t *count)
	Gets byte count received by PDM. More...

---

Data Structure Documentation

struct pdm_edma_transfer_t

Data Fields
volatile uint8_t *	data
	Data start address to transfer. More...
volatile size_t	dataSize
	Total Transfer bytes size. More...
struct _pdm_edma_transfer *	linkTransfer
	linked transfer configurations

Field Documentation

volatile uint8_t* pdm_edma_transfer_t::data

volatile size_t pdm_edma_transfer_t::dataSize

struct _pdm_edma_handle

PDM edma handler.

Data Fields
edma_handle_t *	dmaHandle
	DMA handler for PDM send.
uint8_t	count
	The transfer data count in a DMA request.
uint32_t	receivedBytes
	total transfer count
uint32_t	state
	Internal state for PDM eDMA transfer.
pdm_edma_callback_t	callback
	Callback for users while transfer finish or error occurs.
bool	isLoopTransfer
	loop transfer
void *	userData
	User callback parameter.
edma_tcd_t *	tcd
	TCD pool for eDMA transfer. More...
uint32_t	tcdNum
	TCD number.
uint32_t	tcdUser
	Index for user to queue transfer. More...
uint32_t	tcdDriver
	Index for driver to get the transfer data and size.
volatile uint32_t	tcdUsedNum
	Index for user to queue transfer. More...
uint8_t	endChannel
	The last enabled channel.
uint8_t	channelNums
	total channel numbers

Field Documentation

edma_tcd_t* pdm_edma_handle_t::tcd

uint32_t pdm_edma_handle_t::tcdUser

volatile uint32_t pdm_edma_handle_t::tcdUsedNum

Function Documentation

void PDM_TransferInstallEDMATCDMemory	(	pdm_edma_handle_t *	handle,
		void *	tcdAddr,
		size_t	tcdNum
	)

Parameters

handle	Pointer to EDMA channel transfer handle.
tcdAddr	EDMA head descriptor address.
tcdNum	EDMA link descriptor address.

void PDM_TransferCreateHandleEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle,
		pdm_edma_callback_t	callback,
		void *	userData,
		edma_handle_t *	dmaHandle
	)

This function initializes the PDM slave 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.
base	PDM peripheral base address.
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.

void PDM_TransferSetChannelConfigEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle,
		uint32_t	channel,
		const pdm_channel_config_t *	config
	)

Parameters

base	PDM base pointer.
handle	PDM eDMA handle pointer.
channel	channel index.
config	pdm channel configurations.

status_t PDM_TransferReceiveEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle,
		pdm_edma_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.

1. Scatter gather case: This functio support dynamic scatter gather and staic scatter gather, a. for the dynamic scatter gather case: Application should call PDM_TransferReceiveEDMA function continuously to make sure new receive request is submit before the previous one finish. b. for the static scatter gather case: Application should use the link transfer feature and make sure a loop link transfer is provided, such as:

   * pdm_edma_transfer_t pdmXfer[2] =
   *   {
   *       {
   *       .data  = s_buffer,
   *       .dataSize = BUFFER_SIZE,
   *       .linkTransfer = &pdmXfer[1],
   *       },
   *
   *       {
   *       .data  = &s_buffer[BUFFER_SIZE],
   *       .dataSize = BUFFER_SIZE,
   *       .linkTransfer = &pdmXfer[0]
   *       },
   *   };
   *

2. Multi channel case: This function support receive multi pdm channel data, for example, if two channel is requested,

   * PDM_TransferSetChannelConfigEDMA(DEMO_PDM, &s_pdmRxHandle_0, DEMO_PDM_ENABLE_CHANNEL_0, &channelConfig);
   * PDM_TransferSetChannelConfigEDMA(DEMO_PDM, &s_pdmRxHandle_0, DEMO_PDM_ENABLE_CHANNEL_1, &channelConfig);
   * PDM_TransferReceiveEDMA(DEMO_PDM, &s_pdmRxHandle_0, pdmXfer);
   * 

   Then the output data will be formatted as:

|CHANNEL0 | CHANNEL1 | CHANNEL0 | CHANNEL1 | CHANNEL0 | CHANNEL 1 | ....|

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_TransferTerminateReceiveEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle
	)

This function will clear all transfer slots buffered in the pdm queue. If users only want to abort the current transfer slot, please call PDM_TransferAbortReceiveEDMA.

Parameters

base	PDM base pointer.
handle	PDM eDMA handle pointer.

void PDM_TransferAbortReceiveEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle
	)

This function only aborts the current transfer slots, the other transfer slots' information still kept in the handler. If users want to terminate all transfer slots, just call PDM_TransferTerminateReceiveEDMA.

Parameters

base	PDM base pointer
handle	PDM eDMA handle pointer.

status_t PDM_TransferGetReceiveCountEDMA	(	PDM_Type *	base,
		pdm_edma_handle_t *	handle,
		size_t *	count
	)

Parameters

base	PDM base pointer
handle	PDM eDMA handle pointer.
count	Bytes count received by PDM.

Return values

kStatus_Success	Succeed get the transfer count.
kStatus_NoTransferInProgress	There is no non-blocking transaction in progress.