XBAR: Inter-Peripheral Crossbar Switch

Overview

The MCUXpresso SDK provides a peripheral driver for the Inter-Peripheral Crossbar Switch (XBAR) block of MCUXpresso SDK devices.

The XBAR peripheral driver configures the XBAR (Inter-Peripheral Crossbar Switch) and handles initialization and configuration of the XBAR module.

XBAR driver has two parts:

• Signal connection - This part interconnects input and output signals.
• Active edge feature - Some of the outputs provides active edge detection. If an active edge occurs, an interrupt or a DMA request can be called. APIs handle user callbacks for the interrupts. The driver also includes API for clearing and reading status bit.

Function groups

XBAR Initialization

To initialize the XBAR driver, a state structure has to be passed into the initialization function. This block of memory keeps pointers to user's callback functions and parameters to these functions. The XBAR module is initialized by calling the XBAR_Init() function.

Call diagram

1. Call the "XBAR_Init()" function to initialize the XBAR module.
2. Optionally, call the "XBAR_SetSignalsConnection()" function to Set connection between the selected XBAR_IN[*] input and the XBAR_OUT[*] output signal. It connects the XBAR input to the selected XBAR output. A configuration structure of the "xbar_input_signal_t" type and "xbar_output_signal_t" type is required.
3. Call the "XBAR_SetOutputSignalConfig" function to set the active edge features, such interrupts or DMA requests. A configuration structure of the "xbar_control_config_t" type is required to point to structure that keeps configuration of control register.
4. Finally, the XBAR works properly.

Typical use case

Data Structures
struct	_xbar_control_config
	Defines the configuration structure of the XBAR control register. More...

Typedefs
typedef enum _xbar_active_edge	xbar_active_edge_t
	XBAR active edge for detection.
typedef enum _xbar_request	xbar_request_t
	Defines the XBAR DMA and interrupt configurations.
typedef enum _xbar_status_flag_t	xbar_status_flag_t
	XBAR status flags. More...
typedef struct _xbar_control_config	xbar_control_config_t
	Defines the configuration structure of the XBAR control register. More...

Enumerations
enum	_xbar_active_edge {   kXBAR_EdgeNone = 0U,   kXBAR_EdgeRising = 1U,   kXBAR_EdgeFalling = 2U,   kXBAR_EdgeRisingAndFalling = 3U }
	XBAR active edge for detection. More...
enum	_xbar_request {   kXBAR_RequestDisable = 0U,   kXBAR_RequestDMAEnable = 1U,   kXBAR_RequestInterruptEnalbe = 2U }
	Defines the XBAR DMA and interrupt configurations. More...
enum	_xbar_status_flag_t { kXBAR_EdgeDetectionOut0 }
	XBAR status flags. More...

XBAR functional Operation
void	XBAR_Init (XBAR_Type *base)
	Initializes the XBAR modules. More...
void	XBAR_Deinit (XBAR_Type *base)
	Shutdown the XBAR modules. More...
void	XBAR_SetSignalsConnection (XBAR_Type *base, xbar_input_signal_t input, xbar_output_signal_t output)
	Set connection between the selected XBAR_IN[*] input and the XBAR_OUT[*] output signal. More...
void	XBAR_ClearStatusFlags (XBAR_Type *base, uint32_t mask)
	Clears the edge detection status flags of relative mask. More...
uint32_t	XBAR_GetStatusFlags (XBAR_Type *base)
	Gets the active edge detection status. More...
void	XBAR_SetOutputSignalConfig (XBAR_Type *base, xbar_output_signal_t output, const xbar_control_config_t *controlConfig)
	Configures the XBAR control register. More...

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Data Structure Documentation

struct _xbar_control_config

This structure keeps the configuration of XBAR control register for one output. Control registers are available only for a few outputs. Not every XBAR module has control registers.

Data Fields
xbar_active_edge_t	activeEdge
	Active edge to be detected. More...
xbar_request_t	requestType
	Selects DMA/Interrupt request. More...

Field Documentation

xbar_active_edge_t _xbar_control_config::activeEdge

xbar_request_t _xbar_control_config::requestType

Typedef Documentation

typedef enum _xbar_status_flag_t xbar_status_flag_t

This provides constants for the XBAR status flags for use in the XBAR functions.

typedef struct _xbar_control_config xbar_control_config_t

This structure keeps the configuration of XBAR control register for one output. Control registers are available only for a few outputs. Not every XBAR module has control registers.

Enumeration Type Documentation

enum _xbar_active_edge

Enumerator
kXBAR_EdgeNone	Edge detection status bit never asserts.
kXBAR_EdgeRising	Edge detection status bit asserts on rising edges.
kXBAR_EdgeFalling	Edge detection status bit asserts on falling edges.
kXBAR_EdgeRisingAndFalling	Edge detection status bit asserts on rising and falling edges.

enum _xbar_request

Enumerator
kXBAR_RequestDisable	Interrupt and DMA are disabled.
kXBAR_RequestDMAEnable	DMA enabled, interrupt disabled.
kXBAR_RequestInterruptEnalbe	Interrupt enabled, DMA disabled.

enum _xbar_status_flag_t

This provides constants for the XBAR status flags for use in the XBAR functions.

Enumerator
kXBAR_EdgeDetectionOut0	XBAR_OUT0 active edge interrupt flag, sets when active edge detected.

Function Documentation

void XBAR_Init

(

XBAR_Type *

base

)

This function un-gates the XBAR clock.

Parameters

base	XBAR peripheral address.

void XBAR_Deinit

(

XBAR_Type *

base

)

This function disables XBAR clock.

Parameters

base	XBAR peripheral address.

void XBAR_SetSignalsConnection	(	XBAR_Type *	base,
		xbar_input_signal_t	input,
		xbar_output_signal_t	output
	)

This function connects the XBAR input to the selected XBAR output. If more than one XBAR module is available, only the inputs and outputs from the same module can be connected.

Example:

XBAR_SetSignalsConnection(XBAR, kXBAR_InputTMR_CH0_Output, kXBAR_OutputXB_DMA_INT2);

Parameters

base	XBAR peripheral address
input	XBAR input signal.
output	XBAR output signal.

void XBAR_ClearStatusFlags	(	XBAR_Type *	base,
		uint32_t	mask
	)

Parameters

base	XBAR peripheral address
mask	the status flags to clear.

uint32_t XBAR_GetStatusFlags

(

XBAR_Type *

base

)

This function gets the active edge detect status of all XBAR_OUTs. If the active edge occurs, the return value is asserted. When the interrupt or the DMA functionality is enabled for the XBAR_OUTx, this field is 1 when the interrupt or DMA request is asserted and 0 when the interrupt or DMA request has been cleared.

Example:

uint32_t status;

status = XBAR_GetStatusFlags(XBAR);

Parameters

base	XBAR peripheral address.

Returns

the mask of these status flag bits.

void XBAR_SetOutputSignalConfig	(	XBAR_Type *	base,
		xbar_output_signal_t	output,
		const xbar_control_config_t *	controlConfig
	)

This function configures an XBAR control register. The active edge detection and the DMA/IRQ function on the corresponding XBAR output can be set.

Example:

xbar_control_config_t userConfig;
userConfig.activeEdge = kXBAR_EdgeRising;
userConfig.requestType = kXBAR_RequestInterruptEnalbe;
XBAR_SetOutputSignalConfig(XBAR, kXBAR_OutputXB_DMA_INT0, &userConfig);

Parameters

base	XBAR peripheral address
output	XBAR output number.
controlConfig	Pointer to structure that keeps configuration of control register.