Description

Direct Memory Access Driver.

Introduction

The DMADRV driver supports writing code using DMA which will work regardless of the type of the DMA controller on the underlying microcontroller. Additionally, DMA can be used in several modules that are completely unaware of each other. The driver does not preclude use of the native emlib API of the underlying DMA controller. On the contrary, it will often result in more efficient code and is necessary for complex DMA operations. The housekeeping functions of this driver are valuable even in this use-case.

The dmadrv.c and dmadrv.h source files are in the emdrv/dmadrv folder.

Note: DMA transfer completion callback functions are called from within the DMA interrupt handler.

Configuration Options

Some properties of the DMADRV driver are compile-time configurable. These properties are stored in a file named dmadrv_config.h. A template for this file, containing default values, is in the emdrv/config folder. Currently the configuration options are as follows:

The interrupt priority of the DMA peripheral.
A number of DMA channels to support.
Use the native emlib API belonging to the underlying DMA hardware in combination with the DMADRV API.

Both configuration options will help reduce the driver's RAM footprint.

To configure DMADRV, provide a custom configuration file. This is an example dmadrv_config.h file:

       
        #ifndef __SILICON_LABS_DMADRV_CONFIG_H__
       
        #define __SILICON_LABS_DMADRV_CONFIG_H__
       
        // DMADRV DMA interrupt priority configuration option.
       
        // Set DMA interrupt priority. Range is 0..7, 0 is the highest priority.
       
        #define EMDRV_DMADRV_DMA_IRQ_PRIORITY 4
       
        // DMADRV channel count configuration option.
       
        // A number of DMA channels to support. A lower DMA channel count will reduce
       
        // RAM footprint.
       
        #define EMDRV_DMADRV_DMA_CH_COUNT 4
       
        #endif

The API

This section contains brief descriptions of the API functions. For more information about input and output parameters and return values, click on the hyperlinked function names. Most functions return an error code, ECODE_EMDRV_DMADRV_OK is returned on success, see ECODE - Error Codes and Error Codes for other error codes.

The application code must include dmadrv.h header file.

DMADRV_Init() , DMADRV_DeInit()
These functions initialize or deinitialize the DMADRV driver. Typically, DMADRV_Init() is called once in the startup code.

DMADRV_AllocateChannel() , DMADRV_FreeChannel()
DMA channel reserve and release functions. It is recommended that application code check that DMADRV_AllocateChannel() returns ECODE_EMDRV_DMADRV_OK before starting a DMA transfer.

DMADRV_MemoryPeripheral()
Start a DMA transfer from memory to a peripheral.

DMADRV_PeripheralMemory()
Start a DMA transfer from a peripheral to memory.

DMADRV_MemoryPeripheralPingPong()
Start a DMA ping-pong transfer from memory to a peripheral.

DMADRV_PeripheralMemoryPingPong()
Start a DMA ping-pong transfer from a peripheral to memory.

DMADRV_LdmaStartTransfer()
Start a DMA transfer on an LDMA controller.

DMADRV_StopTransfer()
Stop an ongoing DMA transfer.

DMADRV_TransferActive()
Check if a transfer is ongoing.

DMADRV_TransferCompletePending()
Check if a transfer completion is pending.

DMADRV_TransferDone()
Check if a transfer has completed.

DMADRV_TransferRemainingCount()
Get number of items remaining in a transfer.

Example

Transfer a text string to USART1.

       
        #include "dmadrv.h"
       
        char
       
       str[] =
       
        "Hello DMA !"
       
       ;
      
        unsigned
       
        int
       
       channel;
      
        int
       
       main(
       
        void
       
       )
      
       {
      
        // Initialize DMA.
       
        DMADRV_Init
       
       ();
      
        // Request a DMA channel.
       
        DMADRV_AllocateChannel
       
       ( &channel, NULL );
      
        // Start the DMA transfer.
       
        DMADRV_MemoryPeripheral
       
       ( channel,
      
       dmadrvPeripheralSignal_USART1_TXBL,
      
       (
       
        void
       
       *)&(USART1->TXDATA),
      
       str,
      
        true
       
       ,
      
        sizeof
       
       ( str ),
      
       dmadrvDataSize1,
      
       NULL,
      
       NULL );
      
        return
       
       0;
      
       }

Modules
Error Codes

Functions
Ecode_t	DMADRV_AllocateChannel (unsigned int channelId, void capabilities)
	Allocate (reserve) a DMA channel.

Ecode_t	DMADRV_DeInit (void)
	Deinitialize DMADRV.

Ecode_t	DMADRV_FreeChannel (unsigned int channelId)
	Free an allocated (reserved) DMA channel.

Ecode_t	DMADRV_Init (void)
	Initialize DMADRV.

Ecode_t	DMADRV_MemoryPeripheral (unsigned int channelId, DMADRV_PeripheralSignal_t peripheralSignal, void dst, void src, bool srcInc, int len, DMADRV_DataSize_t size, DMADRV_Callback_t callback, void *cbUserParam)
	Start a memory to a peripheral DMA transfer.

Ecode_t	DMADRV_PeripheralMemory (unsigned int channelId, DMADRV_PeripheralSignal_t peripheralSignal, void dst, void src, bool dstInc, int len, DMADRV_DataSize_t size, DMADRV_Callback_t callback, void *cbUserParam)
	Start a peripheral to memory DMA transfer.

Ecode_t	DMADRV_MemoryPeripheralPingPong (unsigned int channelId, DMADRV_PeripheralSignal_t peripheralSignal, void dst, void src0, void src1, bool srcInc, int len, DMADRV_DataSize_t size, DMADRV_Callback_t callback, void cbUserParam)
	Start a memory to a peripheral ping-pong DMA transfer.

Ecode_t	DMADRV_PeripheralMemoryPingPong (unsigned int channelId, DMADRV_PeripheralSignal_t peripheralSignal, void dst0, void dst1, void src, bool dstInc, int len, DMADRV_DataSize_t size, DMADRV_Callback_t callback, void cbUserParam)
	Start a peripheral to memory ping-pong DMA transfer.

Ecode_t	DMADRV_LdmaStartTransfer (int channelId, LDMA_TransferCfg_t transfer, LDMA_Descriptor_t descriptor, DMADRV_Callback_t callback, void *cbUserParam)
	Start an LDMA transfer.

Ecode_t	DMADRV_PauseTransfer (unsigned int channelId)
	Pause an ongoing DMA transfer.

Ecode_t	DMADRV_ResumeTransfer (unsigned int channelId)
	Resume an ongoing DMA transfer.

Ecode_t	DMADRV_StopTransfer (unsigned int channelId)
	Stop an ongoing DMA transfer.

Ecode_t	DMADRV_TransferActive (unsigned int channelId, bool *active)
	Check if a transfer is running.

Ecode_t	DMADRV_TransferCompletePending (unsigned int channelId, bool *pending)
	Check if a transfer complete is pending.

Ecode_t	DMADRV_TransferDone (unsigned int channelId, bool *done)
	Check if a transfer has completed.

Ecode_t	DMADRV_TransferRemainingCount (unsigned int channelId, int *remaining)
	Get number of items remaining in a transfer.

Typedefs
typedef bool(*	DMADRV_Callback_t ) (unsigned int channel, unsigned int sequenceNo, void *userParam)
	DMADRV transfer completion callback function.

Variables
DMA_DESCRIPTOR_TypeDef	dmaControlBlock []
	uDMA control block array.

Function Documentation

◆ DMADRV_AllocateChannel()

Ecode_t DMADRV_AllocateChannel	(	unsigned int *	`channelId,`
		void *	`capabilities`
	)

Allocate (reserve) a DMA channel.

Parameters

[out]	`channelId`	The channel ID assigned by DMADRV.
[in]	`capabilities`	Not used.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_DeInit()

Ecode_t DMADRV_DeInit ( void )

Deinitialize DMADRV.

If DMA channels are not currently allocated, it will disable DMA hardware and mask associated interrupts.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_FreeChannel()

Ecode_t DMADRV_FreeChannel ( unsigned int channelId )

Free an allocated (reserved) DMA channel.

Parameters

[in] channelId The channel ID to free.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_Init()

Ecode_t DMADRV_Init ( void )

Initialize DMADRV.

The DMA hardware is initialized.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_MemoryPeripheral()

Ecode_t DMADRV_MemoryPeripheral	(	unsigned int	`channelId,`
		DMADRV_PeripheralSignal_t	`peripheralSignal,`
		void *	`dst,`
		void *	`src,`
		bool	`srcInc,`
		int	`len,`
		DMADRV_DataSize_t	`size,`
		DMADRV_Callback_t	`callback,`
		void *	`cbUserParam`
	)

Start a memory to a peripheral DMA transfer.

Parameters

[in]	`channelId`	The channel ID to use for the transfer.
[in]	`peripheralSignal`	Selects which peripheral/peripheralsignal to use.
[in]	`dst`	A destination (peripheral register) memory address.
[in]	`src`	A source memory address.
[in]	`srcInc`	Set to true to enable source address increment (increments according to size parameter).
[in]	`len`	A number of items (of size size) to transfer.
[in]	`size`	An item size, byte, halfword or word.
[in]	`callback`	A function to call on DMA completion, use NULL if not needed.
[in]	`cbUserParam`	An optional user parameter to feed to the callback function. Use NULL if not needed.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_PeripheralMemory()

Ecode_t DMADRV_PeripheralMemory	(	unsigned int	`channelId,`
		DMADRV_PeripheralSignal_t	`peripheralSignal,`
		void *	`dst,`
		void *	`src,`
		bool	`dstInc,`
		int	`len,`
		DMADRV_DataSize_t	`size,`
		DMADRV_Callback_t	`callback,`
		void *	`cbUserParam`
	)

Start a peripheral to memory DMA transfer.

Parameters

[in]	`channelId`	The channel ID to use for the transfer.
[in]	`peripheralSignal`	Selects which peripheral/peripheralsignal to use.
[in]	`dst`	A destination memory address.
[in]	`src`	A source memory (peripheral register) address.
[in]	`dstInc`	Set to true to enable destination address increment (increments according to size parameter).
[in]	`len`	A number of items (of size size) to transfer.
[in]	`size`	An item size, byte, halfword or word.
[in]	`callback`	A function to call on DMA completion, use NULL if not needed.
[in]	`cbUserParam`	An optional user parameter to feed to the callback function. Use NULL if not needed.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_MemoryPeripheralPingPong()

Ecode_t DMADRV_MemoryPeripheralPingPong	(	unsigned int	`channelId,`
		DMADRV_PeripheralSignal_t	`peripheralSignal,`
		void *	`dst,`
		void *	`src0,`
		void *	`src1,`
		bool	`srcInc,`
		int	`len,`
		DMADRV_DataSize_t	`size,`
		DMADRV_Callback_t	`callback,`
		void *	`cbUserParam`
	)

Start a memory to a peripheral ping-pong DMA transfer.

Parameters

[in]	`channelId`	The channel ID to use for the transfer.
[in]	`peripheralSignal`	Selects which peripheral/peripheralsignal to use.
[in]	`dst`	A destination (peripheral register) memory address.
[in]	`src0`	A source memory address of the first (ping) buffer.
[in]	`src1`	A source memory address of the second (pong) buffer.
[in]	`srcInc`	Set to true to enable source address increment (increments according to size parameter).
[in]	`len`	A number of items (of size size) to transfer.
[in]	`size`	An item size, byte, halfword or word.
[in]	`callback`	A function to call on DMA completion, use NULL if not needed.
[in]	`cbUserParam`	An optional user parameter to feed to the callback function. Use NULL if not needed.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_PeripheralMemoryPingPong()

Ecode_t DMADRV_PeripheralMemoryPingPong	(	unsigned int	`channelId,`
		DMADRV_PeripheralSignal_t	`peripheralSignal,`
		void *	`dst0,`
		void *	`dst1,`
		void *	`src,`
		bool	`dstInc,`
		int	`len,`
		DMADRV_DataSize_t	`size,`
		DMADRV_Callback_t	`callback,`
		void *	`cbUserParam`
	)

Start a peripheral to memory ping-pong DMA transfer.

Parameters

[in]	`channelId`	The channel ID to use for the transfer.
[in]	`peripheralSignal`	Selects which peripheral/peripheralsignal to use.
[in]	`dst0`	A destination memory address of the first (ping) buffer.
[in]	`dst1`	A destination memory address of the second (pong) buffer.
[in]	`src`	A source memory (peripheral register) address.
[in]	`dstInc`	Set to true to enable destination address increment (increments according to size parameter).
[in]	`len`	A number of items (of size size) to transfer.
[in]	`size`	An item size, byte, halfword or word.
[in]	`callback`	A function to call on DMA completion, use NULL if not needed.
[in]	`cbUserParam`	An optional user parameter to feed to the callback function. Use NULL if not needed.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_LdmaStartTransfer()

Ecode_t DMADRV_LdmaStartTransfer	(	int	`channelId,`
		LDMA_TransferCfg_t *	`transfer,`
		LDMA_Descriptor_t *	`descriptor,`
		DMADRV_Callback_t	`callback,`
		void *	`cbUserParam`
	)

Start an LDMA transfer.

This function is similar to the emlib LDMA function.

Parameters

[in]	`channelId`	The channel ID to use.
[in]	`transfer`	A DMA transfer configuration data structure.
[in]	`descriptor`	A DMA transfer descriptor, can be an array of descriptors linked together.
[in]	`callback`	An optional callback function for signalling completion. May be NULL if not needed.
[in]	`cbUserParam`	An optional user parameter to feed to the callback function. May be NULL if not needed.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_PauseTransfer()

Ecode_t DMADRV_PauseTransfer ( unsigned int channelId )

Pause an ongoing DMA transfer.

Parameters

[in] channelId The channel ID of the transfer to pause.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_ResumeTransfer()

Ecode_t DMADRV_ResumeTransfer ( unsigned int channelId )

Resume an ongoing DMA transfer.

Parameters

[in] channelId The channel ID of the transfer to resume.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_StopTransfer()

Ecode_t DMADRV_StopTransfer ( unsigned int channelId )

Stop an ongoing DMA transfer.

Parameters

[in] channelId The channel ID of the transfer to stop.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_TransferActive()

Ecode_t DMADRV_TransferActive	(	unsigned int	`channelId,`
		bool *	`active`
	)

Check if a transfer is running.

Parameters

[in]	`channelId`	The channel ID of the transfer to check.
[out]	`active`	True if transfer is running, false otherwise.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_TransferCompletePending()

Ecode_t DMADRV_TransferCompletePending	(	unsigned int	`channelId,`
		bool *	`pending`
	)

Check if a transfer complete is pending.

Will check the channel interrupt flag. This assumes that the DMA is configured to give a completion interrupt.

Parameters

[in]	`channelId`	The channel ID of the transfer to check.
[out]	`pending`	True if a transfer complete is pending, false otherwise.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_TransferDone()

Ecode_t DMADRV_TransferDone	(	unsigned int	`channelId,`
		bool *	`done`
	)

Check if a transfer has completed.

Note: This function should be used in a polled environment. Will only work reliably for transfers NOT using the completion interrupt. On UDMA, it will only work on basic transfers on the primary channel.

Parameters

[in]	`channelId`	The channel ID of the transfer to check.
[out]	`done`	True if a transfer has completed, false otherwise.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

◆ DMADRV_TransferRemainingCount()

Ecode_t DMADRV_TransferRemainingCount	(	unsigned int	`channelId,`
		int *	`remaining`
	)

Get number of items remaining in a transfer.

Note: This function does not take into account that a DMA transfer with a chain of linked transfers might be ongoing. It will only check the count for the current transfer. On UDMA, it will only work on the primary channel.

Parameters

[in]	`channelId`	The channel ID of the transfer to check.
[out]	`remaining`	A number of items remaining in the transfer.

Returns: ECODE_EMDRV_DMADRV_OK on success. On failure, an appropriate DMADRV Ecode_t is returned.

Typedef Documentation

◆ DMADRV_Callback_t

typedef bool(* DMADRV_Callback_t) (unsigned int channel, unsigned int sequenceNo, void *userParam)

DMADRV transfer completion callback function.

The callback function is called when a transfer is complete.

Parameters

[in]	`channel`	The DMA channel number.
[in]	`sequenceNo`	The number of times the callback was called. Useful on long chains of linked transfers or on endless ping-pong type transfers.
[in]	`userParam`	Optional user parameter supplied on DMA invocation.

Returns: When doing ping-pong transfers, return true to continue or false to stop transfers.

Variable Documentation

◆ dmaControlBlock

DMA_DESCRIPTOR_TypeDef dmaControlBlock[]

uDMA control block array.

Used with Series-0 only

DMADRV - DMA Driver

Description

Introduction

Configuration Options

The API

Example

Modules

Functions

Typedefs

Variables

Function Documentation

◆ DMADRV_AllocateChannel()

◆ DMADRV_DeInit()

◆ DMADRV_FreeChannel()

◆ DMADRV_Init()

◆ DMADRV_MemoryPeripheral()

◆ DMADRV_PeripheralMemory()

◆ DMADRV_MemoryPeripheralPingPong()

◆ DMADRV_PeripheralMemoryPingPong()

◆ DMADRV_LdmaStartTransfer()

◆ DMADRV_PauseTransfer()

◆ DMADRV_ResumeTransfer()

◆ DMADRV_StopTransfer()

◆ DMADRV_TransferActive()

◆ DMADRV_TransferCompletePending()

◆ DMADRV_TransferDone()

◆ DMADRV_TransferRemainingCount()

Typedef Documentation

◆ DMADRV_Callback_t

Variable Documentation

◆ dmaControlBlock