Timer

The hardware abstraction layer provides functions for managing callbacks based on timer expiry. These timers should be run from the main loop but also from systemProcessEvents when called within the WP43 code.

Functions

Defines

MAX_TIMER_ID

Typedefs

typedef void (*timerCallback_t)(uint16_t param)

Enums

enum timerId_t

Values:

enumerator tidTimeUpdate

enumerator tidAutoRepeat

enumerator tidShowNop

enumerator tidAsmActive

enumerator tidTimerAppRedraw

enumerator tidTimerAppDetectWrapAround

Functions

uint32_t timerRun(void)

void timerReset(void)

Cancel all running timers.

Timers need to be restarted after this call, and should also be configured with timerConfig.

void timerConfig(timerId_t nr, timerCallback_t func)

Configure the callback function for a given timer.

This function will only be called once when the timer has expired. If it should be called repeatedly then the callback function should call timerStart again. timerConfig must be called before timerStart is called.

Parameters

• nr – [in] timer ID

• func – [in] callback function called when a timer expires

void timerStart(timerId_t nr, uint16_t param, uint32_t time)

Set an expiry on a given timer.

The callback function configured in timerConfig will be called when the specified time has elapsed. It will only be called once, not repeatedly. If it is required to repeat then the callback function configured by timerConfig should call timerStart again.

Parameters

• nr – [in] timer ID

• param – [in] parameter that is passed to the callback function

• time – [in] time is milliseconds until the timer expires

void timerStop(timerId_t nr)

Stop a timer.

This will stop a running timer causing it to not fire. It is safe to call on a stopped timer, but will have no effect. The timer must be configured with timerConfig before timerStop is called though.

Parameters

• nr – [in] timer ID

bool timerIsRunning(timerId_t nr)

Query whether a timer is running.

Returns whether the given timer is running, that is that it has been started with timerStart, not stopped with timerStop, and it has not yet reached the expiry time.

Parameters

• nr – [in] timer ID

Returns

true if the timer is still running

Example

The configuration of the timers should be done early on in initialisation after first calling timerReset:

timerReset();
timerConfig(tidAutoRepeat, cbAutoRepeat);
timerConfig(tidShowNop,    cbShowNop);

where cbShowNop is the callback function for when the tidShowNop timer expires.

When the timer expires the timer callback function will be called once (not repeatedly). If the timer should be called repeatedly then the callback can start the timer again.

void cbShowNop(uint16_t param) {
  // ...
  // Restart timer to get callback in another 200 milliseconds
  timerStart(tidShowNop, param, 200);
}

void myFunction(void) {
  timerStart(tidShowNop, 0, 200);
}