SHIP:Node:timer

Node Home

Node Type	Description
timer	Generates delays and timed alarm events.

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

Ancestors

timer nodes are only permitted in the layout area. The following layout area nodes are permitted to have timers as descendants:

Node Type	Description
box†	A generic rectangular container, available as a reusable resource or layout element.
display†	Contains the visual GUI layout for a specific LCD display/touch set.
group†	Lightweight node that encloses other nodes for pure organizational benefit, or to create an array of nodes.
layout	Top of the Layout Area within a SHIP GUI, which completely describes how the GUI is visually organized.
page†	Visual layout area for a specific GUI "page", or "screen"
text†	Defines a text resource or a visual text representation.
timer†	Generates delays and timed alarm events.
variable†	Run-time value accessible by scripts and able to generate events on change.

^†timer nodes are permitted directly underneath these nodes.

Descendants

The following nodes are permitted within timers:

Node Type	Description
constant†	Defines a constant value for use in SHIPTide properties or SAIL scripts.
group†	Lightweight node that encloses other nodes for pure organizational benefit, or to create an array of nodes.
listener†	Monitors one or more properties (including variable values!) for changes, and on changes invokes a script.
script	Run-time algorithms, written in SHIPSail.
timer†	Generates delays and timed alarm events.
variable†	Run-time value accessible by scripts and able to generate events on change.

^†only these nodes are permitted directly underneath the timer node.

Properties

Property	Data Type	Description
name**	String	The name used to identify this node in SHIPTide.
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.

Overview

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 every 0.1 seconds. 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 true the associated script action is taken, often including restarting the timer.

Timer Modes of Operation

The two timer properties oneshot and autoreload determine the operational mode of a timer. These modes are:

Mode	oneshot	autoreload	Operation
Mode 0	false	false	Manual free-running operation When enabled, the timer will count down to zero then pause until a new non-zero count value is loaded by a Sail script. Setting the period has no effect.
Mode 1	false	true	Automatic free-running operation When enabled, the timer will count down to zero then re-load the value from the period and restart the count down process. A period value of zero will cause the timer to pause (still enabled) until a non-zero value is loaded into the value or period.
Mode 2	true	false	Manual one-shot operation When enabled with value non-zero, the timer will count down to zero then self-set enabled to false. The timer will restart when a non-zero value is loaded and the timer is re-enabled by a Sail script. Setting the period has no effect.
Mode 3	true	true	Automatic one-shot operation When enabled with value non-zero, the timer will count down to zero then self-set enabled to false. When re-enabled with value zero, the value will be reloaded from the period and the timer will restart.

Mode 0

Manual free-running operation

To start a timer in this mode, ensure:

• oneshot is false, indicating a free running timer mode
• autoreload false, meaning the timer will not automatically reload the value from the period
• enabled is true
• value is loaded with a value greater than zero

In this mode, the timer will count down until the timer expires (the value hits 0), at which point:

• alarm will go true (if it is not already true)
• enabled will stay true
• The timer will pause counting at value zero

Since the timer is still enabled, the timer will immediately restart counting down when a new non-zero count value is loaded by a Sail script.

Hence, a listener-script on the alarm could simply:

timer.alarm = false; // clear alarm
timer.value = 50; // restart immediately at 5 seconds

to restart the timer at 5 seconds. The period property is not used by the timer in this mode, and is available to the GUI designer to store any Integer value, such as the desired reload value. The setup of the timer could therefore be:

timer.period = 50;
timer.oneshot = false; // free running mode
timer.autoreload = false; // no automatic reload from period
timer.value = timer.period; // start at 5 seconds
timer.enabled = true;       // start now 

Of course, all these values could be configured on the timer node in SHIPTide without any code all. Then the listener-script could simply be:

timer.alarm = false; // clear alarm
timer.value = timer.period; // restart immediately at whatever the period is set to

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.

Mode 1

Automatic free-running operation

To start a timer in this mode, ensure:

• oneshot is false, indicating a free running timer mode
• autoreload true, meaning the timer will automatically reload the value from the period
• enabled is true

If the value is zero when the timer is enabled, the timer will load the value from the period.

In this mode, the timer will count down until the timer expires (the value hits 0), at which point:

• alarm will go true (if it is not already true)
• enabled will stay true
• The timer will reload its value from its period and restart counting immediately

If the period is zero when a reload is attempted, the timer will remain enabled but paused until either:

• value is loaded with a non-zero value, or,
• period is loaded with a non-zero value (which will be auto-loaded into value immediately)).

The setup of the timer could therefore be:

timer.period = 50;
timer.oneshot = false; // free running mode
timer.autoreload = true; // automatic reload from period
timer.value = 0; // timer will automatically load from period when 0
timer.enabled = true;       // start now 

These values can be configured on the timer node in SHIPTide without any code all.

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. For example, the listener-script on the alarm could simply be:

timer.alarm = false; // clear alarm
// do some action; timer is still running and was auto reloaded.

Mode 2

Manual one-shot operation

To start a timer in this mode, ensure:

• oneshot is true, indicating one-shot timer mode
• autoreload false, meaning the timer will not automatically reload the value from the period
• enabled is true

If the value is zero when the timer is enabled, the timer will not start and the enabled property will not go true.

In this mode, the timer will count down until the timer expires (the value hits 0), at which point:

• alarm will go true (if it is not already true)
• enabled will self-set to false and the timer will stop.

To re-start thetimer, the value must be reloaded with a non-zero value and the enabled must be re-set to true.

Setting the period has no effect in this mode, and this property can be used as a placeholder for the value a script may wish to use as a reload value.

The setup of the timer could therefore be:

timer.period = 50;
timer.oneshot = true; // one shot mode
timer.autoreload = false; // do not automatic reload from period
timer.value = timer.period; // must set up value manually
timer.enabled = true;       // start now 

These values can be configured on the timer node in SHIPTide and do not need to be initialized in a Sail script.

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. For example, the listener-script on the alarm could simply be:

timer.alarm = false; // clear alarm
timer.value = timer.period; // manually reload period

// do some action; timer is halted

timer.enabled = true; // restart timer

Mode 3

Automatic one-shot operation

To start a timer in this mode, ensure:

• oneshot is true, indicating one-shot timer mode
• autoreload true, meaning the timer will automatically reload the value from the period
• enabled is true

If the value is zero when the timer is enabled, the timer will re-load the value from the period which, if non-zero, will restart the timer count down. If the period is zero, enabled will not go true as requested.

In this mode, the timer will count down until the timer expires (the value hits 0), at which point:

• alarm will go true (if it is not already true)
• enabled will self-set to false and the timer will stop.

To re-start thetimer, simply re-set enabled to true. As described above, the timer will re-load the value from the period which, if non-zero, will restart the timer count down.

The setup of the timer could therefore be:

timer.period = 50;
timer.oneshot = true; // one shot mode
timer.autoreload = true; //  automatic reload from period
timer.value = 0; // will reload from period
timer.enabled = true;       // start now 

These values can be configured on the timer node in SHIPTide and do not need to be initialized in a Sail script.

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. For example, the listener-script on the alarm could simply be:

timer.alarm = false; // clear alarm
// do some action; timer is halted
timer.enabled = true; // restart timer, will auto-reload from period

Examples

Animation Timers

Here is a complete example of a timer, including an associated listener and script which increment a variable every 0.3 seconds:

In this example, the timer is set up as a oneshot with a 0.3 second period. Each time the alarm goes true, the listener awakes and runs the script. The script increments a Short variable named animationCounter.

animationCounter can now be the foundation for numerous listeners throughout the GUI. They will wake up every time animationCounter increments (once every 0.3 seconds) and can use the value to determine which animation image needs to be displayed. For example, if a given animation is composed of 3 cycling images, (animationCounter % 3) could be used in a switch statement to select and display the correct image in the cycle.