LPI2C Master DMA Driver

Overview

Data Structures
struct	lpi2c_master_edma_handle_t
	Driver handle for master DMA APIs. More...

Typedefs
typedef void(*	lpi2c_master_edma_transfer_callback_t )(LPI2C_Type *base, lpi2c_master_edma_handle_t *handle, status_t completionStatus, void *userData)
	Master DMA completion callback function pointer type. More...

Master DMA
void	LPI2C_MasterCreateEDMAHandle (LPI2C_Type *base, lpi2c_master_edma_handle_t *handle, edma_handle_t *rxDmaHandle, edma_handle_t *txDmaHandle, lpi2c_master_edma_transfer_callback_t callback, void *userData)
	Create a new handle for the LPI2C master DMA APIs. More...
status_t	LPI2C_MasterTransferEDMA (LPI2C_Type *base, lpi2c_master_edma_handle_t *handle, lpi2c_master_transfer_t *transfer)
	Performs a non-blocking DMA-based transaction on the I2C bus. More...
status_t	LPI2C_MasterTransferGetCountEDMA (LPI2C_Type *base, lpi2c_master_edma_handle_t *handle, size_t *count)
	Returns number of bytes transferred so far. More...
status_t	LPI2C_MasterTransferAbortEDMA (LPI2C_Type *base, lpi2c_master_edma_handle_t *handle)
	Terminates a non-blocking LPI2C master transmission early. More...

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Data Structure Documentation

struct _lpi2c_master_edma_handle

Note

The contents of this structure are private and subject to change.

Data Fields
LPI2C_Type *	base
	LPI2C base pointer. More...
bool	isBusy
	Transfer state machine current state. More...
uint8_t	nbytes
	eDMA minor byte transfer count initially configured. More...
uint16_t	commandBuffer [7]
	LPI2C command sequence. More...
lpi2c_master_transfer_t	transfer
	Copy of the current transfer info. More...
lpi2c_master_edma_transfer_callback_t	completionCallback
	Callback function pointer. More...
void *	userData
	Application data passed to callback. More...
edma_handle_t *	rx
	Handle for receive DMA channel. More...
edma_handle_t *	tx
	Handle for transmit DMA channel. More...
edma_tcd_t	tcds [3]
	Software TCD. More...

Field Documentation

LPI2C_Type* lpi2c_master_edma_handle_t::base

bool lpi2c_master_edma_handle_t::isBusy

uint8_t lpi2c_master_edma_handle_t::nbytes

uint16_t lpi2c_master_edma_handle_t::commandBuffer[7]

lpi2c_master_transfer_t lpi2c_master_edma_handle_t::transfer

lpi2c_master_edma_transfer_callback_t lpi2c_master_edma_handle_t::completionCallback

void* lpi2c_master_edma_handle_t::userData

edma_handle_t* lpi2c_master_edma_handle_t::rx

edma_handle_t* lpi2c_master_edma_handle_t::tx

edma_tcd_t lpi2c_master_edma_handle_t::tcds[3]

Three are allocated to provide enough room to align to 32-bytes.

Typedef Documentation

typedef void(* lpi2c_master_edma_transfer_callback_t)(LPI2C_Type *base, lpi2c_master_edma_handle_t *handle, status_t completionStatus, void *userData)

This callback is used only for the non-blocking master transfer API. Specify the callback you wish to use in the call to LPI2C_MasterCreateEDMAHandle().

Parameters

base	The LPI2C peripheral base address.
handle	Handle associated with the completed transfer.
completionStatus	Either #kStatus_Success or an error code describing how the transfer completed.
userData	Arbitrary pointer-sized value passed from the application.

Function Documentation

void LPI2C_MasterCreateEDMAHandle	(	LPI2C_Type *	base,
		lpi2c_master_edma_handle_t *	handle,
		edma_handle_t *	rxDmaHandle,
		edma_handle_t *	txDmaHandle,
		lpi2c_master_edma_transfer_callback_t	callback,
		void *	userData
	)

The creation of a handle is for use with the DMA APIs. Once a handle is created, there is not a corresponding destroy handle. If the user wants to terminate a transfer, the LPI2C_MasterTransferAbortEDMA() API shall be called.

For devices where the LPI2C send and receive DMA requests are OR'd together, the txDmaHandle parameter is ignored and may be set to NULL.

Parameters

	base	The LPI2C peripheral base address.
[out]	handle	Pointer to the LPI2C master driver handle.
	rxDmaHandle	Handle for the eDMA receive channel. Created by the user prior to calling this function.
	txDmaHandle	Handle for the eDMA transmit channel. Created by the user prior to calling this function.
	callback	User provided pointer to the asynchronous callback function.
	userData	User provided pointer to the application callback data.

status_t LPI2C_MasterTransferEDMA	(	LPI2C_Type *	base,
		lpi2c_master_edma_handle_t *	handle,
		lpi2c_master_transfer_t *	transfer
	)

The callback specified when the handle was created is invoked when the transaction has completed.

Parameters

base	The LPI2C peripheral base address.
handle	Pointer to the LPI2C master driver handle.
transfer	The pointer to the transfer descriptor.

Return values

#kStatus_Success	The transaction was started successfully.
kStatus_LPI2C_Busy	Either another master is currently utilizing the bus, or another DMA transaction is already in progress.

status_t LPI2C_MasterTransferGetCountEDMA	(	LPI2C_Type *	base,
		lpi2c_master_edma_handle_t *	handle,
		size_t *	count
	)

Parameters

	base	The LPI2C peripheral base address.
	handle	Pointer to the LPI2C master driver handle.
[out]	count	Number of bytes transferred so far by the non-blocking transaction.

Return values

#kStatus_Success
#kStatus_NoTransferInProgress	There is not a DMA transaction currently in progress.

status_t LPI2C_MasterTransferAbortEDMA	(	LPI2C_Type *	base,
		lpi2c_master_edma_handle_t *	handle
	)

Note

It is not safe to call this function from an IRQ handler that has a higher priority than the eDMA peripheral's IRQ priority.

Parameters

base	The LPI2C peripheral base address.
handle	Pointer to the LPI2C master driver handle.

Return values

#kStatus_Success	A transaction was successfully aborted.
kStatus_LPI2C_Idle	There is not a DMA transaction currently in progress.