Trigger - Add trigger or function port to subsystem or model - Simulink (original) (raw)

Add trigger or function port to subsystem or model

Libraries:
Simulink / Ports & Subsystems
HDL Coder / Ports & Subsystems

Description

The Trigger block adds an external signal or message port to control the execution of a subsystem or a model. To enable this functionality, add this block to a Subsystem block or at the root level of a model that is referenced in aModel block.

Then, configure the Trigger block to execute a subsystem or model:

• Once at each time step, when the value of the control signal changes in a way that you specify.
• Multiple times during a time step, when the control signal is a function-call event from a Stateflow® chart, Function-Call Generator block, orS-Function block.
• Based on messages received at the control port.

Examples

Ports

Output

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If the Trigger type isrising,falling,either, orfunction-call, the port outputs a value that identifies a control signal, returned as a scalar or vector. For each element of the input signal, the value at a given time step is:

• 1 for a signal that causes a rising trigger
• -1 for a signal that causes a falling trigger
• 2 for a function-call event
• 0 in all other cases

If the Trigger type ismessage, the port outputs data extracted from message received at the control port.

Dependencies

To enable this port, select Show output port or set Trigger type tomessage.

Data Types: double | int8

Parameters

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Main

Select the type of control signal that executes a subsystem or model.

• rising — Trigger execution of subsystem or model when the control signal rises from a negative or zero value to a positive value. If the initial value is negative, a rising signal to zero triggers execution.
• falling — Trigger execution of subsystem or model when the control signal falls from a positive or a zero value to a negative value. If the initial value is positive, a falling signal to zero triggers execution.
• either — Trigger execution of subsystem or model when the control signal is either rising or falling.
• function-call — Execute subsystem or model when the control port receives a function-call event from a Stateflow chart, Function-Call Generator block, S-Function block, or Hit Crossing block.
• message — Trigger execution of subsystem when a message is available at the control port. The block must be inside a subsystem.

Programmatic Use

Select this parameter to create a Simulink Function block by configuring a Subsystem block that is callable with arguments from a function caller. The Trigger block must reside within the subsystem. You can edit the function prototype that displays on the block face to specify input and output arguments for the block.

Clear this parameter to remove the configuration.

Dependencies

To display and enable this parameter, set Trigger type tofunction-call.

Programmatic Use

Specify whether to execute the Simulink Function block asynchronously for a subsystem containing this Trigger port block.

• Select this parameter to model asynchronous execution where the caller (client) makes a request to call the function (server). The function is executed based on the ordering defined in the Schedule Editor and then returns the output arguments to the caller.
• Clear this parameter to model synchronous execution where the caller calls the function and the function runs immediately then returns the output arguments to the caller.

Dependencies

To display and enable this parameter, set Trigger type to function-call, select Treat as a Simulink Function, and setFunction visibility toport.

Programmatic Use

Specify the function name for a Simulink Function block. Alternatively, you can specify the name by editing the function prototype on the face of the block.

Dependencies

To display and enable this parameter, set Trigger type to function-call and select Treat as a Simulink Function.

Programmatic Use

Select scope of Simulink Function block within subsystem or model.

• scoped — Limit accessibility of function to:
  • Hierarchic level containing the Simulink Function block and levels below.
  • One hierarchical level above with qualification.
• global — Function accessible from any part of the model hierarchy.
• port — Function accessible only through an exporting function port created by a Function Element block.

Dependencies

To display and enable this parameter, set Trigger type to function-call and select Treat as a Simulink Function.

Programmatic Use

For a Simulink Function block with port visibility, specify the name of the exporting function port created by a Function Element block through which the function can be called.

Example: 'ServerPort'

Dependencies

To display and enable this parameter, set Trigger type to function-call, select Treat as a Simulink Function, and setFunction visibility toport.

Programmatic Use

Control activating the variant control (condition) defined with theVariant Control parameter.

Select this parameter to activate variant control of the subsystem. Selecting this parameter:

• Enables the Variant control parameter.
• Displays a variant badge on the face of the block indicating that variant conditions are enabled.

Clear this parameter to deactivate variant control of the subsystem.

Dependencies

To display and enable this parameter, set Trigger type to function-call and select Treat as Simulink function.

Programmatic Use

Specify variant control (condition) expression that executes a variantSimulink Function block when the expression evaluates to true.

• (inherit) — Default value for variant control. Inherits the variant condition from the correspondingFunction Caller blocks in the model. WhenVariant Control is set as(inherit) the value forGenerate preprocessor conditionals is inherited automatically from the Function Caller block in the model.
• logical expression — A logical (Boolean) expression or aSimulink.VariantExpression object representing a logical expression. The function is activated when the expression evaluates to true.
  If you want to generate code for your model, define the variables in the expression asSimulink.Parameter objects.

Dependencies

To display and enable this parameter, set Trigger type to function-call, select Treat as a Simulink Function, and select Enable variant condition.

Programmatic Use

Control enclosing variant choices within C preprocessor conditional statements.

Select this parameter to enclose variant choices within C preprocessor conditional statements (#if) when generating code for an ERT target.

Dependencies

To display and enable this parameter, select Enable variant condition .

Programmatic Use

Select how to set block state values when the subsystem or model is disabled.

• held — Leave the block states at their current values.
• reset — Reset the block state values.
• inherit — Use theheld orreset setting from the parent subsystem initiating the function-call. If the parent of the initiator is the model root, the inherited setting isheld. If the trigger has multiple initiators, set the parents of all initiators to eitherheld orreset.

Dependencies

To enable this parameter, set Trigger Type tofunction-call.

This parameter setting applies only if the model explicitly enables and disables the function-call subsystem. For example:

• The function-call subsystem resides in an enabled subsystem. In this case, the model enables and disables the function-call subsystem along with the parent subsystem.
• The function-call initiator that controls the function-call subsystem resides in an enabled subsystem. In this case, the model enables and disables the function-call subsystem along with the enabled subsystem containing the function-call initiator.
• The function-call initiator is a Stateflow event bound to a particular state. SeeControl Function-Call Subsystems by Using bind Actions (Stateflow).
• The function-call initiator is an S-function that explicitly enables and disables the function-call subsystem. See ssEnableSystemWithTid for an example.

Programmatic Use

Select when to propagate variable-size signals.

• During execution — Propagate variable-size signals at each time step.
• Only when enabling — Propagate variable-size signals when executing a Subsystem block or Model block containing anEnable port, Trigger port withTrigger type set tofunction-call, or Action Port block. When you select this option, sample time must be periodic.

Dependencies

To display and enable this parameter for a Trigger port block, set Trigger type toFunction-call.

Programmatic Use

Control display of an output port for a signal that identifies the trigger signal or function-call event signal.

Select this parameter to display the output port and determine which signal caused the trigger signal or function-call event. The width of the output port signal is the width of the control signal. The signal value is:

• 1 for a signal that causes a rising trigger
• -1 for a signal that causes a falling trigger
• 2 for a function-call event
• 0 in all other cases

Clear this parameter to remove the output port.

Dependencies

To display and enable this parameter, set Trigger type to an option other thanmessage.

Programmatic Use

Select the output port data type for the signal that identifies the trigger signal or function-call event signal.

• auto — Data type from the port connected to the output
• double — Double value
• int8 — Integer value

Dependencies

To enable this parameter, select Show output port.

The Trigger block ignores the Data type override setting for the Fixed-Point Tool.

Programmatic Use

Select the calling rate for a subsystem or model.

• triggered — Apply to applications that do not have a periodic function-call frequency. A function-call initiator can execute a triggered (aperiodic) function-call subsystem one or more times per time step and can provide a series of aperiodic function-call events.
• periodic — A function-call initiator can execute a periodic function-call system only once per time step and must provide a series of periodic function-call events.. A Stateflow chart is an example of a function-call initiator.

Dependencies

To enable this parameter, set Trigger type to Function-call.

Programmatic Use

Specify the time interval between function calls to a subsystem or model containing this Trigger port block. If the actual calling rate for the subsystem or model differs from the time interval this parameter specifies, the software displays an error.

• Ts — Scalar where Ts is the time interval
• [Ts, To] — Vector whereTs is the time interval andTo is the initial time offset
• -1 — Inherited time interval from the control signal

Dependencies

To enable this parameter, set Trigger type to function-call and Sample time type toperiodic.

Programmatic Use

Select this parameter to detect zero crossings.

Dependencies

To enable this parameter, set Trigger type torising,falling, oreither.

Programmatic Use

Select the initial state of the trigger control signal.

• compatibility (no trigger on first evaluation) — No trigger at the first evaluation of trigger signal. If you choose this option and theTrigger block is in a subsystem where the states are reset, the block does not reset.
• zero — Zero. Helps to evaluate a rising or falling trigger signal at the first time step.
• positive — Positive value. Helps to evaluate a falling trigger signal at the first time step.
• negative — Negative value. Helps to evaluate a rising trigger signal at the first time step.

Dependencies

To display and activate this parameter, set Trigger type to rising,falling, oreither.

Programmatic Use

For a subsystem triggered by message input, specify timing of execution.

• on message available — Trigger execution of subsystem and pull messages whenever one or more messages are available at the control port.
• on sample time hit — At each time step, check whether a message is available at the control port. If so, pull one message and trigger execution of subsystem. If no message is available, do not execute subsystem at that time step.

Dependencies

To display and activate this parameter, set Trigger type to message.

Programmatic Use

For a subsystem triggered by message availability, specify execution mode.

Clear this parameter for immediate mode, in which the subsystem executes as soon as a message is available at the control port, which pushes the message to the subsystem without a queue buffering the message.

Select this parameter for scheduled mode, which allows subsystem execution to be deferred after a specific Simulink® task while staying at the same time step.

Dependencies

To display and activate this parameter, set Trigger type to message andTrigger time to on message available.

Programmatic Use

Signal Attributes

Specify dimensions for the trigger signal attached externally aModel block and passed into the referenced model.

• 1 — Scalar signal
• [n] — Vector signal of widthn
• [m n] — Matrix signal havingm rows and n columns
• -1 — Inherited dimensions

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Specify time interval between block method executions for the block driving the trigger signal.

• -1 — Inherited time interval
• Ts — Scalar where Ts is the time interval
• [Ts, To] — Vector whereTs is the time interval andTo is the initial time offset

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Specify minimum value for the trigger signal attached externally to aModel block and passed to the inside of the block.

The software uses this value to perform:

• Simulation range checking. See Specify Signal Ranges.
• Automatic scaling of fixed-point data types.
• Optimization of generated code. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. See Optimize using the specified minimum and maximum values (Embedded Coder).

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Specify maximum value for the trigger signal attached externally to aModel block and passed to the inside of the block.

The software uses this value to perform:

• Simulation range checking. See Specify Signal Ranges.
• Automatic scaling of fixed-point data types.
• Optimization of generated code. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. See Optimize using the specified minimum and maximum values (Embedded Coder).

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Select data type for the trigger signal attached externally to aModel block and passed to the inside of the block.

• Inherit: auto — Inherited data type
• double — Double-precision floating point
• single — Single-precision floating point
• int8 — Signed 8-bit integer
• uint8 — Unsigned 8-bit integer
• int16 — Signed 16-bit integer
• uint16 — Unsigned 16-bit integer
• int32 — Signed 32-bit integer
• uint32 — Unsigned 32-bit integer
• int64 — Signed 64-bit integer
• uint64 — Unsigned 64-bit integer
• boolean — Boolean with a value oftrue or false
• fixdt(1,16) — Signed 16-bit fixed point number with binary point undefined
• fixdt(1,16,0) — Signed 16-bit fixed point number with binary point set to zero
• fixdt(1,16,2^,0) — Signed 16-bit fixed point number with slope set to 2^0 and bias set to 0
• <data type expression> — Data type object, for example a Simulink.NumericType object

You cannot enter the name of a Simulink.Bus object as a data type expression.

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Select data type category and display drop-down lists to help you define the data type.

• Built in — Display menus for data type and Data type override.
• Fixed point — Display menus forSignedness,Scaling, and Data type override.
• Expression — Display text box for entering an expression.

Dependencies

To enable this parameter, select the Show data type assistant button .

Control how missing workspace data is estimated when loading data from the MATLAB® workspace.

Select this parameter to linearly interpolate output at time steps for which no corresponding workspace data exists.

Clear this parameter to set the output at such time steps equal to the output at the most recent time step for which data exists.

Dependencies

To display and enable this parameter for a Trigger port block at the root-level of a model, set Trigger type to rising,falling, oreither.

Programmatic Use

Block Characteristics

Extended Capabilities

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HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

For more information, see HDL Code Generation in Triggered Subsystem.

HDL Architecture

This block has one default HDL architecture.

Restriction

You cannot generate HDL code for a Trigger Block that has Trigger type set to function-call ormessage.

Version History

Introduced before R2006a