Winter-Spring 2001 Codesign of Embedded Syste

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Debug and Trace Facilities in SystemC

Part ofHW/SW Codesign of

Embedded Systems Course (CE 40-226)

Winter-Spring 2001 Codesign of Embedded Syste

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Today programme Some SystemC examples Simulation and Debugging in

SystemC

Winter-Spring 2001 Codesign of Embedded Syste

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DFF Example

DFFInput_gen

disp

lay

clock_gen

d q

Winter-Spring 2001 Codesign of Embedded Syste

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DFF Example (cont’d)

DFFInput_gen

disp

lay

clock_gen

d qSC_MODULE(DFF) {

sc_in<bool> d, clk;

sc_out<bool> q;

void update();

SC_CTOR(DFF){

SC_METHOD(update);

sensitive_pos(clk);

}

};

void DFF::update()

{

q = d;

cout <<"Time: “<< sc_time_stamp()<<". DFF: output updated to “<< q << endl;

}

Winter-Spring 2001 Codesign of Embedded Syste

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DFF Example (cont’d)

DFFInput_gen

disp

lay

clock_gen

d qSC_MODULE(input_gen){

sc_in<bool> clk;

sc_out<bool> input_to_dff;

sc_logic val;

void gen()

{

input_to_dff = val;

val = !val;

cout<<"Time: ” <<sc_time_stamp() << ". input_gen: generating ” << input_to_dff<<" for next clock.\n"<<val;}

SC_CTOR(input_gen) {

SC_METHOD(gen);

sensitive_pos(clk);

val = 0;

}

};

Winter-Spring 2001 Codesign of Embedded Syste

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DFF Example (cont’d)

DFFInput_gen

disp

lay

clock_gen

d qSC_MODULE(display) {

sc_in<bool> output_of_dff;

void show() {

cout<<"Time: "<< sc_time_stamp()<<". display: showing "<< output_of_dff<< endl;

}

SC_CTOR(display) {

SC_METHOD(show);

sensitive<<output_of_dff;

}

};

Winter-Spring 2001 Codesign of Embedded Syste

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DFF Example (cont’d)int sc_main(int , char*argv[])

{

sc_clock clock_gen("CLK_GEN", 10, 0.5);

sc_signal<bool> d, q;

input_gen gen("Gen");

gen.clk(clock_gen.signal());

gen.input_to_dff(d);

DFF ff("Flip Flop");

ff.clk(clock_gen);

ff.d(d);

ff.q(q);

display disp("Disp");

disp.output_of_dff(q);

sc_start(50);

return 0;

}

DFFInput_gen

disp

lay

clock_gen

d q

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and Debugging Using SystemC Simulation Control

Advanced Simulation Control Techniques Tracing Waveforms

Creating The Trace File Tracing Scalar Variable and Signals Tracing Variables and Signals of Aggregate

Types Tracing Variable and Signal Arrays

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Simulation Control

sc_start(double simulation_duration) sc_stop() sc_time_stamp() Debugging aid

read/print signal, port, and variable values For ports and signals: The printed value is the

current value, not the value just written to it

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Simulation Control

Advanced Simulation control techniques

Instead of sc_start:sc_initialize();// init SystemC scheduler

// set signals by writing values to them

sc_cycle(double); // simulates signal writes, then advances simulation time by its argument value

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Tracing Waveforms

Supported waveform formats VCD (Value Change Dump) ASCII WIF (Wave Intermediate Format) ISDB (Integrated Signal DataBase)

Notes Variables local to a function cannot be traced scalar, array, and aggregate types can be traced Different types of trace files can be created during the

same simulation run A signal or variable can be traced any number of times

in different trace formats

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Tracing wave forms

Creating the trace file:sc_trace_file *tf;tf = sc_create_vcd_trace_file(“trace_file”);

For other trace file formats sc_create_wif_trace_file(<filename>); sc_create_isdb_trace_file(<filename>);

To close the trace file sc_close_vcd_trace_file(<trace-file pointer>); sc_close_wif_trace_file(<trace-file pointer>); sc_close_isdb_trace_file(<trace-file pointer>);

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Tracing scalar variable and signals

sc_trace(<trace-file pointer>, <traced variable>, <string>);

Examplesc_signal<int> a;

float b;

sc_trace(trace_file, a, “MyA”);

sc_trace(trace_file, b, “B”);

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Tracing variable and signals of

aggregate type Solution 1: trace each element

separately Solution 2: define a special trace

function for the type Will be covered later

Winter-Spring 2001 Codesign of Embedded Syste

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Simulation and … (cont’d) Tracing variable and signal arrays

Solution 1: trace each element separately

Solution 2: define a special trace function for the array

Will be covered later

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What we learned today More SystemC Examples Simulation and Debugging using

SystemC