The generated code includes scheduling code that executes application code based on sample times specified in the model. An ARM® Cortex®-M processor typically uses a bare-metal scheduler for scheduling application code. While the example presented here shows how to implement a bare-metal scheduler, the same conceptual steps also apply to an operating system scheduler.
Create and add a new OperatingSystem
object, os
,
to your Target
(Embedded Coder Support Package for ARM Cortex-A Processors) object, tgt
,
by calling addNewBaremetalScheduler
with the name
of the scheduler, for example, 'My Baremetal Scheduler'
.
scheduler = addNewBaremetalScheduler(tgt,'My Baremetal Scheduler');
Do not delete the Baremetal Scheduler
object, scheduler
,
from the MATLAB® workspace before you save the target.
Note
The scheduler provided with base target for ARM Cortex-M target only can be used with the GNU toolchain.
Confirm that the operating system 'My Baremetal
Scheduler'
is added to your target.
show(tgt);
My ARM Cortex M Board Display Name My ARM Cortex M Board My New Deployer 1 My Baremetal Scheduler 0
The output shows that bare-metal scheduler 'My Baremetal Scheduler'
is
added to the target. However, note that the scheduler is not used for the hardware
'My ARM Cortex M Board'
, and this fact is denoted by showing
0
in the corresponding position for the hardware.
Map the BaremetalScheduler
object, scheduler
,
to the Hardware
(Embedded Coder Support Package for ARM Cortex-A Processors) object, hw
.
map(tgt,hw,scheduler);
Confirm that the bare-metal scheduler 'My Baremetal Scheduler'
is used for the hardware 'My ARM Cortex M Board'
show(tgt);
My ARM Cortex M Board Display Name My ARM Cortex M Board My New Deployer 1 My Baremetal Scheduler 1
The output shows that the bare-metal scheduler 'My Baremetal
Scheduler'
is used for the hardware 'My ARM Cortex
MBoard'
, and this fact is denoted by showing 1
in
the corresponding position for the hardware.
Create and add a new BaseRateTrigger
object, baseRateTrigger
,
to the BaremetalScheduler
object, scheduler
,
by calling addNewBaremetalSchedular
with the name
of the scheduler, for example, 'My BaremetalScheduler'
.
baseRateTrigger = addNewBaseRateTrigger(scheduler,'My Base Rate Trigger');
Do not delete the BaseRateTrigger
object, baseRateTrigger
,
from the MATLAB workspace before you save the target.
Set the properties of the BaseRateTrigger
object, baseRateTrigger
,
as needed for your hardware. For example, you may set the source code
function that configures the base rate trigger by setting the ConfigurationFcn
property.
baseRateTrigger.ConfigurationFcn = 'myBaseRateTrigger_ConfigFcn(modelBaseRate)';
The configuration function typically sets up a hardware interrupt,
such as a timer, at the rate that corresponds to the base rate of
the model. For that purpose, the function takes the model base rate
as a parameter modelBaseRate
. The generated code
will call the configuration function from its main
function.
Similarly, set the BaseRateTrigger
object
properties EnableInterruptFcn
and DisableInterruptFcn
to
register the functions that enable and disable the base rate trigger
interrupt.
baseRateTrigger.EnableInterruptFcn = 'myBaseRateTriggerInterruptEnable()'; baseRateTrigger.DisableInterruptFcn = 'myBaseRateTriggerInterruptDisable()';
Save the information that describes a target to its framework.
saveTarget(tgt);
Test that the scheduler works correctly.
testTarget(tgt,'scheduler')
Upon completion of the test, a summary result is displayed.
If the test PASSED
, then you can proceed with adding
the next feature. Otherwise, if the test FAILED
,
a link to the test diagnostic logs is shown below the test summary.
Note
Until an External Mode feature is added to the target, the scheduler
cannot be fully tested and will return Incomplete
in
the test.
In MATLAB, on the Home tab, select New
> Simulink Model. The default name of the model is untitled
.
Click File > Save As and save your model
as test
.
In the model, select Simulation > Model Configuration Parameters.
In the Configuration Parameters dialog box, select Solver
.
From the Type list, select Fixed-step
.
From the Solver list, select auto
.
In the Configuration Parameters dialog box, select
the Hardware Implementation
tab.
Set Hardware board to the hardware
you registered, for example, 'My ARM Cortex M Board'
.
On the Solver
tab, set
Tasking mode for periodic sample times to Auto.
On the Optimization
tab,
clear Block reduction.
On the Code Generation > Interface tab, select MAT-file logging. Click OK.
In MATLAB, on the Home tab, select Simulink® Library.
In the Simulink library, open Sources and add a
Constant block to your model. Double-click the
Constant block and set Sample time to
1
.
Add another Constant block to the model.
Double-click the Constant1
block and set Sample
time to 2
and Constant value to 2
.
In the Simulink library, open Sinks and add a To
Workspace block to your model. Click the block and set Save
format to Array
.
Copy and paste this To Workspace block to the model.
Connect the Constant block to the To Workspace, and Constant1 and To Workspace1 .
Build your model. After the build completes, the code will run on your hardware. You need to verify whether the code actually runs. The technique you use for verification will be specific to your hardware.