Timer
This GOAL core module provides functionalities for:
hard timers with an operating system (Figure 18),
hard timers without an operating system (Figure 19) and
soft timers (Figure 20).
Hard timers are high prioritized and handled interrupt-controlled or operating system-specific. Soft timers are low prioritized and handled loop-controlled. Both kinds of timer base on platform-specific timers. The value range of the timers depends on the platform-specific timer configuration. The standard GOAL system requires a minimal time period of 1 ms.
The accesses to the GOAL timers are protected by the GOAL locking mechanism.
Figure: typical case for hard timer with operating system
Figure: typical case for hard timer without operating system
Figure: soft timer handling
The timers can be used as:
single shot timer or
periodic timer
The timer type can be configured by function goal_timerSetup().
GOAL files:
goal_timer.[h,c], goal_timer_cli.c
example:
not available
Callback functions
There are the following callback functions to connect the timer with other functionality:
Table: cbTimerFunc()
Prototype | void cbTimerFunc(void *pArg) | |
Description | This callback function is always called if the current time stamp is captured. | |
Parameter | pArg | specific arguments used by the callback function |
Return values | none | |
Category | Mandatory | |
Registration | during runtime via function goal_timerSetup | |
Table: cbStopTimerFunc()
Prototype | void cbStopTimerFunc(void *pArg) | |
Description | This function is called once if the timer is stopped. | |
Parameter | pArg | specific arguments used by the callback function |
Return values | none | |
Category | optional | |
Registration | during runtime via function goal_timerStopCb() | |
Platform API
GOAL requires the following indication function to manage a platform-specific timer as base for GOAL timers:
Table: goal_targetTimerInit()
Prototype | GOAL_STATUS_T goal_targetTimerInit(void) |
Description | This indication function initializes a platform-specific timer and is called in stage GOAL_STAGE_TIMER_PRE in the state GOAL_FSA_INIT_GOAL. |
Parameters | none |
Return values | GOAL return status, see Chapter: GOAL status |
Category | mandatory |
Condition | none |
Table: goal_targetTimerCreate()
Prototype | GOAL_STATUS_T goal_targetTimerCreate(GOAL_TIMER_T *pTmr) | |
Description | This indication function creates a platform-specific timer for a GOAL hard timer. | |
Parameters | pTmr | handle for the GOAL hard timer |
Return values | GOAL return status, see Chapter: GOAL status | |
Category | mandatory for GOAL hard timers | |
Condition | none | |
Table: goal_targetTimerDelete()
Prototype | GOAL_STATUS_T goal_targetTimerDelete(GOAL_TIMER_T *pTmr) | |
Description | This indication function deletes a platform-specific timer for a GOAL hard timer. | |
Parameters | pTmr | handle for the GOAL hard timer |
Return values | GOAL return status, see Chapter: GOAL status | |
Category | mandatory for GOAL hard timers | |
Condition | none | |
Table: goal_targetTimerStart()
Prototype | GOAL_STATUS_T goal_targetTimerStart(GOAL_TIMER_T *pTmr) | |
Description | This indication function starts a platform-specific timer for a GOAL hard timer. | |
Parameters | pTmr | handle for the GOAL hard timer |
Return values | GOAL return status, see Chapter: GOAL status | |
Category | mandatory for GOAL hard timers | |
Condition | none | |
Table: goal_targetTimerStop()
Prototype | GOAL_STATUS_T goal_targetTimerStop(GOAL_TIMER_T *pTmr) | |
Description | This indication function stops a platform-specific timer for a GOAL hard timer. | |
Parameters | pTmr | handle for the GOAL hard timer |
Return values | GOAL return status, see Chapter: GOAL status | |
Category | mandatory for GOAL hard timers | |
Condition | none | |
Command line interface
Command | time current |
Description | Prints the current timestamp of the GOAL system to the command line interface. |
Parameter | none |
Implementation guidelines
Use a periodic soft timer and start the timer immediately
Create a handle for the timer:
GOAL_TIMER_T *pSoftTimer;Create a soft timer of low priority in state GOAL_FSA_INIT:
goal_timerCreate(&pSoftTimer, GOAL_TIMER_LOW);The soft timer shall be triggered every 1000 ms periodically and shall be started immediately. The timer is configured as follow:
goal_timerSetup(pSoftTimer, GOAL_TIMER_PERIODIC, 1000, cbTimerFunc, NULL, GOAL_TRUE);The callback function is called if the timer is expired again and again.
Stop the timer without calling a callback function after it is expired the next time:
Delete the timer:
Use a single soft timer and start the timer in the application
Create a handle for the timer:
Create a soft timer of low priority in state GOAL_FSA_INIT:
The soft timer shall be triggered only once after 1000 ms and shall be started by the application. The timer is configured as follow:
Start the timer in the application:
Stop the timer without calling a callback function:
Delete the timer:
Stop hard timer with callback function
Create a handle for the timer:
Create a hard timer of high priority in state GOAL_FSA_INIT:
The hard timer shall be triggered every 1000 ms periodically and shall be started immediately. The timer is configured as follow:
The callback function is called if the timer is expired again and again.
Stop the timer with calling a callback function:
Delete the timer: