SHIP:Node:timer

Node Home

Animations and delayed events or pauses require periodic or one-shot timers. The timer node fills this need in Template:SHIP.

The timer node is a 0.1s resolution event timer which can be set up to be free running or one-shot, with an auto-reload capability.

Parent Nodes

The following nodes are permitted to hold this node:

• box
• display
• group
• text
• page
• variable

Child Nodes

The following nodes are permitted to exist within this node:

• constant
• listener
• variable

Properties

Property	Data Type	Description
SHIP:Property:timer:name
enabled	Boolean	If true (default if unset) this timer is enabled.
alarm*	Boolean	Set to true at run-time when a timer's count value transitions from 1 to 0.
autoreload	Boolean	Determines whether or not period will be loaded into value automatically after it expires.
oneshot	Boolean	If set, the timer will stop when the count value is zero and self-set the enabled property to false
period	Integer	Value used by a timer to reload the countdown value after the timer has expired.
value	Integer	Remaining count-down value, in 10ths of a second, of the timer

*available at SHIPEngine run time only and cannot be set in SHIPTide. Use a Sail script at shiplaunch time if this property needs to be set when the GUI starts to run.

**available only in SHIPTide; cannot be accessed from Sail scripts at run-time.

Operation

The timer is a 0.1s resolution event timer which can be set up to be free-running or one-shot, with an auto-reload capability. The timer's value property represents the current remaining time on the given timer, in tenths of a seconds. For example, if the timer.value is 34, there are 3.4 seconds left on the timer before it hits 0.

When enabled is set to true and the timer.value property is non-zero, the timer begins to count down, with the value property decrementing ever 0.1Hz. On a count value transition from 1 to 0 (the timer expires), the alarm property is set to true. The alarm must be manually reset (set to false) by a Sail script.

In the majority of designs, a listener is attached to the alarm. When the alarm goes Template:Reference the associated script action is taken, often including restarting the timer.

The oneshot and autoreload Properties

A "one shot" timer is a timer that stops when it has completed its count. The opposite of a "one shot" timer is a "free running" timer which, when it competes its count, automatically restarts counting in a "free running" mode. The timer node supports both types of operation based on the oneshot value.

When a timer expires and the oneshot property is true, the timer.enabled property is set to false, stopping the timer. Hence the term "one shot", since the timer is now halted and must be re-configured and re-started manually from a Sail script.

However when a timer expires and all the following conditions are true:

• the oneshot is set to false (expressing a desire to be a free-running timer)
• the autoreload is set to true
• the period is set to a value greater than 0

then

• the enabled property is kept unchanged (true)
• the value will be automatically reloaded from period
• the timer will restart counting down.

This is the free-running mode of the timer.

In both one-shot and free-running modes, care must be taken to clear the alarm property in a Sail script before the next alarm or the next alarm event may be missed.

listeners and timers

Normally, a listener will be set to listen to a timer's alarm property. For example, the following shows a typical listener-script pair acting on an alarm when the timer expires:

One Shot, No Auto Reload

This mode is set when oneshot is true and autoreload is false.

When the alarm goes true (on a 1 to 0 transition on value), the timer:

• sets enabled false
• sets alarm true

The timer then stops (i.e. a "one shot"), and must be restarted in a Sail script, generally from a listener listeningto the alarm to go true.

If the enabled is subsequently set in a Sail script true, the act of re-enabling the timer with value 0 causes an auto reload of the value from period and the timer commences the count-down cycle again.

• reloads value from {{Prop|

f true, leaves enabled true, reloads value from period and restarts counting down

property and:

• if true, leaves enabled true, reloads value from period and restarts counting down
• if false, sets enabled false, reloads value from period and restarts counting down

In the vast majority of use cases, a listener is attached to the alarm, and in the associated script the alarm is reset.

When enabled is set to true and the value is non-zero, the timer begins to count down, with the value property decrementing ever 0.1Hz. When the {{Prop|timer|

in that it counts down from the programmed value until it hits 0 which then sets the alarm. If auto A GUI is generally composed of numerous graphically designed layout screens. Touch buttons navigate within an interactive GUI page and also cause screens to change from one to another. Since the word "screen" can easily be confused with the physical glass screen (vs. the GUI pixel content on the screen), SHIP uses the term "page" instead. The page in the GUI contains the visual layout for a specific GUI page. You can, and probably will, have many pages in a given GUI.