© 2003 The MathWorks, Inc. 1 Importing C code into Simulink for Signal Processing Applications © 2003 The MathWorks, Inc. Colin Warwick [email protected] #2 in the webinar series “Today’s Simulink for Wireless Design” MATLAB and Simulink are registered trademarks of The MathWorks, Inc.
© 2003 The MathWorks, Inc. 1 Importing C code into Simulink for Signal Processing Applications © 2003 The MathWorks, Inc. Colin Warwick [email protected].
Jan 14, 2016
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Importing C code into Simulinkfor Signal Processing Applications
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Colin Warwick
#2 in the webinar series “Today’s Simulink for Wireless Design”
MATLAB and Simulink are registered trademarks of The MathWorks, Inc.
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Agenda
What's available? Interoperability between MATLAB, Simulink, and C
Why call C from Simulink? The MathWorks’ System-Level Design Flow
How? S-function Builder block – new in R13 (August 2002) C-code S-function – full API
Same “full strength” API as we use to build our blocks
Webex live Q&A
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Flexible usage model: Six permutations
C
SimulinkMATLAB
From Simulink,
call C
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Flexible usage model: Six permutations
S-function BuilderC-code S-function
CSimulink
M-code S-functionCaution: interpreted, not compiledMATLABSimulink
>> sim(‘mymodel’)SimulinkMATLAB
MEXActiveX/COM & DDE
CMATLAB
Engine or COM[x,y,t] = sim(‘mymodel’,u0)SimulinkC
MATLAB EngineActiveX/COM & DDEMATLAB Compiler & runtime
MATLABC
How?Call…From…
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MATLAB
Simulink
Why use Simulink as a framework for your C-code?
Capture and validate an executable specification before component-level implementation
Use our blocks as a first cut and as a test harness
Capture your IP in C using Simulink as a framework
Validated Executable Specification
DSP/MCUSoftware Tools
EDA Tools
Analog & DigitalHardware
DSP & MCUSoftware
IMPLEMENTATION TOOLS
C
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Why use Simulink as a framework for your C-code? Jump start your project
Prebuilt Blocksets and application examples MathWorks, 3rd parties
Test bench surrounding your product Stimulus generation
From a simple sin wave to a complete transmitter & channel model
Response instrumentation, visualization Time (eye), I-Q (constellation), frequency (spectra)
M-file scripting (test executive), BER versus Eb/No plot Block diagram paradigm
Intuitive capture of concurrent simulation time Divide and conquer Self-documenting
Algorithm visualization Library of reusable blocks
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Structure of code to be imported: `core and leaves´
test_slicer.exe
//test_slicer.cmain(){ for(){ slicer(); }}
//slicer.cslicer(){ return;}
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Try it! Quick demo. Today’s demos use…
Simulink(simulink.dll & matlab.exe)
Optional: Symbolic DebuggerSee Tech Note 1601 for a list
User-defined Blocks (“S-function .dll”)in a block diagram (“Model” .mdl)
MATLAB Central
.c .h
Compiler: see Tech Note 1601 for a list
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Structure of code after import: `wrapped leaves´ Call your `leaf´ code from a wrapper to interface with
Simulink Compile both and link .dll Simulink calls the DLL using several functions
(“methods”) wrap_slicer.dll
Simulink //wrap_slicer.cmdlOutputs(S){ slicer();}
//slicer.c//definition// of//slicer()
UNIX is a registered trademark of The Open Group
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The “S-function” DLL contains several methods
mdlInitializeSizes()
mdlInitializeSampleTimes()
mdlOutputs()
mdlTerminate()
yt = f(t, ut)y = outputs, t = timeu = inputs
Done?n
y
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What about leaf functions with states?
States preserved across time steps Independent set of states per instance
FIR, IIR, coders, decoders Also known as...
Computer science: “Re-entrant persistent storage” Object-oriented: “property” C++: “member variable”
Different from… static variables in C are persistent but shared, not re-
entrant If a leaf contains static data it can only be instantiated
once
int always_one(void){ int y = 0; y = y + 1; return y;}
int up(void){ static int y = 0; y = y + 1; return y;}
int counter(int *z){ *z = *z + 1; return *z;}
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Two main types of state available in Simulink
Discrete states, xd
Read-only (const) in the mdlOutput() method Available in S-Function Builder block and full S-function
Work vectors, w Read-write in mdlOutput() Presently only accessible from full S-function API
statesxd, w
input u output y=f(t,xd,w,u)
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Approach depends on code structure
1) “Output-update” structure – use S-function Builder block Leaf with separate output and update functions Use “discrete states”, update them in mdlUpdate()
2) General structure or advanced needs – use full S-function Leaf with output and update functions intermixed Use “work vectors” , update them in mdlOutputs()
yt = f(t, xt, ut), xt+ t = g(t, xt, ut)y = outputs, t = time, x = states, u = inputs
[xt+ t , yt]= f(t, xt, ut)
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1) “Output-update” leaf structure
mdlInitializeSizes()
mdlInitializeSampleTimes()
mdlOutputs()
mdlTerminate()
xt+t = g(t, xt, ut)Done?
n
y
mdlUpdate()
yt = f(t, xt, ut)y = outputs, t = timex = states, u = inputs
“Division of labor is preferred”
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2) General leaf structure
mdlInitializeSizes()
mdlInitializeSampleTimes()
mdlOutputs()
mdlTerminate()
yt = f(t, wt, ut)wt+t = g(t, wt, ut)y = outputst = timew = work vecu = inputs
Done?n
y
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Demonstrations
S-function Builder block features Slicer: a memoryless block IIR Filter: a block with memory
Output-update structure S-function Builder A Discrete state Output in mdlOutputs()and update in mdlUpdate()
General structure Full S-function 1-element Work vector Output and update in mdlOutputs()
Using the sample code as a resource Tour of the S-function reference material
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Summary
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MATLAB
Simulink
Why use Simulink as a framework for your C-code?
Capture and validate an executable specification before component-level implementation
Use our blocks as a first cut and as a test harness
Capture your IP in C using Simulink as a framework
Validated Executable Specification
DSP/MCUSoftware Tools
EDA Tools
Analog & DigitalHardware
DSP & MCUSoftware
IMPLEMENTATION TOOLS
C
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Further Information on Products and Services
Twelve compilers across nine platforms - Tech Note 1601 mathworks.com/support/tech-notes/v5/1600/1601.shtml
Documentation, including templates and sample code Writing S-functions
File Download for this webinar matlabcentral.com
Consulting – Jump Start mathworks.com/consulting
Thankyou!
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Webex Q&A session
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Webinar End
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