Delay Utility Functions

Macros
#define	MXC_DELAY_SEC(s)   (((uint32_t)s) * 1000000UL)
#define	MXC_DELAY_MSEC(ms)   (ms * 1000UL)
#define	MXC_DELAY_USEC(us)   (us)

Typedefs
typedef void(*	mxc_delay_complete_t) (int result)

Functions
int	MXC_Delay (uint32_t us)
int	MXC_DelayAsync (uint32_t us, mxc_delay_complete_t callback)
int	MXC_DelayCheck (void)
void	MXC_DelayAbort (void)
void	MXC_DelayHandler (void)

Detailed Description

Asynchronous delay routines based on the SysTick Timer.

Macro Definition Documentation

MXC_DELAY_MSEC

#define MXC_DELAY_MSEC

(

ms

)

(ms * 1000UL)

Macro used to specify a microsecond timing parameter in milliseconds.

x = MSEC(3) // 3ms -> x = 3,000

MXC_DELAY_SEC

#define MXC_DELAY_SEC

(

s

)

(((uint32_t)s) * 1000000UL)

Macro used to specify a microsecond timing parameter in seconds.

x = SEC(3) // 3 seconds -> x = 3,000,000

MXC_DELAY_USEC

#define MXC_DELAY_USEC

(

us

)

(us)

Macro used to specify a microsecond timing parameter.

x = USEC(3) // 3us -> x = 3

Typedef Documentation

mxc_delay_complete_t

typedef void(* mxc_delay_complete_t) (int result)

The callback routine used by MXC_DelayAsync() when the delay is complete or aborted early.

Parameters

result

See Error Codes for the list of error codes.

Function Documentation

MXC_Delay()

int MXC_Delay

(

uint32_t

us

)

Blocks and delays for the specified number of microseconds.

Uses the SysTick to create the requested delay. If the SysTick is running, the current settings will be used. If the SysTick is not running, it will be started.

Parameters

us	microseconds to delay

Returns

E_NO_ERROR if no errors, error if unsuccessful.

MXC_DelayAbort()

void MXC_DelayAbort

(

void

)

Stops an asynchronous delay previously started.

Precondition

Start the asynchronous delay by calling MXC_Delay_start().

MXC_DelayAsync()

int MXC_DelayAsync	(	uint32_t	us,
		mxc_delay_complete_t	callback
	)

Starts a non-blocking delay for the specified number of microseconds.

Uses the SysTick to time the requested delay. If the SysTick is running, the current settings will be used. If the SysTick is not running, it will be started.

Note

MXC_Delay_handler() must be called from the SysTick interrupt service routine or at a rate greater than the SysTick overflow rate.

Parameters

us	microseconds to delay
callback	Function pointer to the function to call after the delay has expired.

Returns

E_NO_ERROR if no errors, E_BUSY if currently servicing another delay request.

MXC_DelayCheck()

int MXC_DelayCheck

(

void

)

Returns the status of a non-blocking delay request.

Precondition

Start the asynchronous delay by calling MXC_Delay_start().

Returns

E_BUSY until the requested delay time has expired.

MXC_DelayHandler()

void MXC_DelayHandler

(

void

)

Processes the delay interrupt.

This function must be called from the SysTick IRQ or polled at a rate greater than the SysTick overflow rate.