el_trigger.h File Reference

#include "el_common.h"
#include "el_process.h"

Go to the source code of this file.

Typedefs
typedef bool(*	el_condition )(void *)

Enumerations
enum	el_trigger_event_type {   EL_EVENT_NONE = 0, EL_EVENT_INTERNAL_A = 1, EL_EVENT_INTERNAL_B = 2, EL_EVENT_INTERNAL_C = 3,   EL_EVENT_INTERNAL_D = 4, EL_EVENT_INTERNAL_E = 5, EL_EVENT_INTERNAL_F = 6, EL_EVENT_IR_RECEIVER_INCOME = 10,   EL_EVENT_UART1_RECEIVED = 11, EL_EVENT_UART2_RECEIVED = 12, EL_EVENT_ACCELEROMETER_UPDATE = 20, EL_EVENT_IR_PROXIMITY_UPDATE = 21,   EL_EVENT_CAMERA_FRAME_UPDATE = 22 }

Functions
el_handle	el_create_trigger ()
	create a trigger in the system More...
void	el_delete_trigger (el_handle trigger)
	delete the trigger More...
void	el_trigger_enable (el_handle h)
	enable a trigger More...
void	el_trigger_disable (el_handle h)
	disable a trigger More...
el_bool	el_trigger_is_enabled (el_handle h)
	check whether a trigger More...
void	el_trigger_set_event (el_handle h, el_trigger_event_type e)
	set the event of the trigger More...
void	el_trigger_set_condition (el_handle h, el_condition f)
	set the condition callback function of the trigger More...
void	el_trigger_set_process (el_handle h, el_process func)
	set the process entry function of the trigger More...
el_uint32	el_trigger_get_counter (el_handle h)
	get the number of times the trigger passed its condition More...
void	el_trigger_issue_internal_event (el_enum e)
	issue an internal event More...

Detailed Description

Author

Jianing Chen

Enumeration Type Documentation

enum el_trigger_event_type

This enum is used in el_trigger_set_event to specify the event of a trigger. Internal events are manually triggered using el_trigger_issue_internal_event.

Enumerator
EL_EVENT_NONE	no event
EL_EVENT_INTERNAL_A	internal event A
EL_EVENT_INTERNAL_B	internal event B
EL_EVENT_INTERNAL_C	internal event C
EL_EVENT_INTERNAL_D	internal event D
EL_EVENT_INTERNAL_E	internal event E
EL_EVENT_INTERNAL_F	internal event F
EL_EVENT_IR_RECEIVER_INCOME	when the ir receiver receives data
EL_EVENT_UART1_RECEIVED	when UART1 receives data
EL_EVENT_UART2_RECEIVED	when UART2 receives data (not implemented yet)
EL_EVENT_ACCELEROMETER_UPDATE	when the accelerometer output is updated (120 Hz)
EL_EVENT_IR_PROXIMITY_UPDATE	when the ir proximity sensor outputs are updated (30 Hz)
EL_EVENT_CAMERA_FRAME_UPDATE	when a new image frame from the camera is ready (9~18 fps)

Function Documentation

el_handle el_create_trigger

(

)

create a trigger in the system

Returns

handle of the trigger

This function create a trigger in the system. It returns a handle to the trigger created. This handle is used to refer the trigger in the related functions.

void el_delete_trigger

(

el_handle

trigger

)

delete the trigger

Parameters

handle

of the trigger

void el_trigger_enable

(

el_handle

h

)

enable a trigger

Parameters

h	handle of the trigger

Only when a trigger is enabled, its event will be effective. A trigger is enabled by default after its creation.

void el_trigger_disable

(

el_handle

h

)

disable a trigger

Parameters

h	handle of the trigger

When a trigger is disabled, its event will be ignored. A trigger is automatically disabled when its process is launched.

el_bool el_trigger_is_enabled

(

el_handle

h

)

check whether a trigger

Parameters

h	handle of the trigger

Returns

the enabling status

void el_trigger_set_event	(	el_handle	h,
		el_trigger_event_type	e
	)

set the event of the trigger

Parameters

h	handle of the trigger
e	type of the event within the category

This function defines the event of the trigger.

void el_trigger_set_condition	(	el_handle	h,
		el_condition	f
	)

set the condition callback function of the trigger

Parameters

h	handle of the trigger
f	pointer to the callback function

When the event of the trigger occurs, the trigger's condition callback will be called. If this callback function returns true, the trigger passes the condition. Otherwise, the trigger does not pass the condition.

If a trigger does not have a condition callback (by default), the trigger will automatically pass it's condition.

void el_trigger_set_process	(	el_handle	h,
		el_process	func
	)

set the process entry function of the trigger

Parameters

h	handle of the trigger
func	pointer to the process function

When the trigger passes its condition and it has a registered process, the process will be launched while the trigger will be disabled automatically.

The parameter of the process function of a trigger will be assigned with the handle of the trigger. The following code can be used to make the handle more explicit:

void TriggerA_Process(void*arg){
    el_handle this_trigger = arg;
    
    // the program to be executed
    ...
    
    // re-enable the trigger if the trigger is supposed to be periodic. 
    el_trigger_enable(this_trigger);
    
}

To learn more about the usage of a process, see Process.

el_uint32 el_trigger_get_counter

(

el_handle

h

)

get the number of times the trigger passed its condition

Parameters

h	handle of the trigger

Returns

counter of the trigger

For each time the trigger passes its condition, its counter will +1.

void el_trigger_issue_internal_event

(

el_enum

e

)

issue an internal event

Parameters

e	event type (must be internal events)

This will affect those triggers using "EL_EVENT_INTERNAL_<*>" as their events.