MCUXpresso SDK API Reference Manual  Rev. 0
NXP Semiconductors
 All Data Structures Functions Variables Typedefs Enumerations Enumerator Groups Pages
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...
 

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_trx
 Handle for receive DMA channel. More...
 
edma_handle_ttx
 Handle for transmit DMA channel. More...
 
edma_tcd_t tcds [2]
 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[2]

Two 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
baseThe LPI2C peripheral base address.
handleHandle associated with the completed transfer.
completionStatusEither #kStatus_Success or an error code describing how the transfer completed.
userDataArbitrary 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
baseThe LPI2C peripheral base address.
[out]handlePointer to the LPI2C master driver handle.
rxDmaHandleHandle for the eDMA receive channel. Created by the user prior to calling this function.
txDmaHandleHandle for the eDMA transmit channel. Created by the user prior to calling this function.
callbackUser provided pointer to the asynchronous callback function.
userDataUser 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
baseThe LPI2C peripheral base address.
handlePointer to the LPI2C master driver handle.
transferThe pointer to the transfer descriptor.
Return values
#kStatus_SuccessThe transaction was started successfully.
kStatus_LPI2C_BusyEither 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
baseThe LPI2C peripheral base address.
handlePointer to the LPI2C master driver handle.
[out]countNumber of bytes transferred so far by the non-blocking transaction.
Return values
#kStatus_Success
#kStatus_NoTransferInProgressThere 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
baseThe LPI2C peripheral base address.
handlePointer to the LPI2C master driver handle.
Return values
#kStatus_SuccessA transaction was successfully aborted.
kStatus_LPI2C_IdleThere is not a DMA transaction currently in progress.