systemc model of d-flip-flop

[ankit]

1) I will be thankful if i could get some support to resolve error in the attachment as i have tried to implement a pre-defined example.

 

2) for what time  wait() statement is used in method tb_input

 

3) please guide me a bit about hierarchy ( module instantiation ) syntax part

 

4) how to view output in waveform

#include "systemc.h"

SC_MODULE (d_ff) 
{
	sc_in<bool> d;
	sc_in<bool> q;
	bool clk;

SC_CTOR (d_ff) 
{
	SC_METHOD(flop);
	sensitive<<clk.pos();
}

void flop()
{
	q.write(d.read());
}

};

// hierarchy
SC_MODULE (d_ff_4) 
{
	sc_in<bool> d;
	sc_out<bool> q3;
	sc_signal<bool> q0,q1,q2;
	bool clk;

	d_ff d1,d2,d3,d4;

SC_CTOR(d_ff_4) : d1("d1"), d2("d2"),d3("d3"),d4("d4")
{
	d1.d(d);
	d1.clk(clk);
	d1.q(q0);

	d2.d(q0);
	d2.clk(clk);
	d2.q(q1);

	d3.d(q1);
	d3.clk(clk);
	d3.q(q2);

	d4.d(q2);
	d4.clk(clk);
	d4.q(q3);
}

};

//test bench

SC_MODULE(tb) 
{
	sc_out<bool> d;
	bool clk;

void tb_input() 
{
	d.write(false);
	wait();
	d.write(true);
	wait();
	sc_stop();
}

SC_CTOR(tb)
{
	SC_THREAD(tb_input);
	sensitive<<clk.pos();
}
};

//top

int sc_main(int argc, char* argv[]) 
{
	sc_clock testclk("testclock", 10, SC_NS,0.5);

	d_ff d_111("d_111");
	d_mast.flop();

	d_ff_4 d_112("d_112");

	tb t1("t1");
	t1.tb_input();

	sc_start();

return (0);
}

[apfitch]

It would help to post the error message.

However the error that stands out is q in your dff should be an output (sc_out<bool>), not an input,

 

The wait() in tb_input waits until the rising edge of clk, which is every 10 ns.

 

I'm not sure what you're asking about hierarchy. Have you seen this tutorial?

 

http://www.doulos.com/knowhow/systemc/tutorial/

 

 

regards

Alan

[apfitch]

And the clock in your dff model should be declared

sc_in<boo> clk;

 

Alan

[susharmas]

Hello Sir, 

 

Can you please help me to find out the error in this small code. I am newbie to the SystemC and not able to debug it.

I am designing the D flip flop in SystemC. Here below is the code and error:

 

//////////////////////////////////////////////////////////////////////

//dff.cpp

/////////////////////////////////////////////////////////////////////

#include "systemc.h"

 

SC_MODULE(dff){

     sc_in<bool> din;

sc_in<bool> clk;

sc_out<bool> out;

 

void func();

 

       SC_CTOR(dff){

  SC_THREAD(func);

  sensitive_pos<<clk;

  }

};

 

void dff::func()

{

 out.write(din.read());

}

 

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 

AND BELOW IS THE TB FILE:  dff_main.cpp

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 

 

#include "systemc.h"

#include "dff.cpp"

 

int sc_main(int argc, char* argv[]){

      

     sc_signal<bool> din;

sc_signal<bool> out;

 

sc_clock clk("clk", 10, 0.5, 0, true);

 

dff inst("inst");

inst.din(din);

inst.clk(clk);

inst.out(out);

 

sc_start(100, SC_NS);

 

sc_trace_file *tf = sc_create_vcd_trace_file("inst");

    sc_trace(tf, din, "din");

sc_trace(tf, clk, "clk");

sc_trace(tf, out, "out");

 

 

din.write(0);

wait(5, SC_NS);

 

din.write(1);

wait(10, SC_NS);

 

din.write(0);

wait(15, SC_NS);

 

din.write(1);

wait(10, SC_NS);

 

din.write(0);

wait(20, SC_NS);

 

din.write(1);

wait(10, SC_NS);

 

din.write(0);

wait(8, SC_NS);

 

sc_stop();

 

  return (0);

  

}

 

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

And the error is:

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

 

\dff.dir/objects.a(dff.cpp.obj):dff.cpp:(.text+0x0): multiple definition of `dff::func()'

CMakeFiles\dff.dir/objects.a(dff_main.cpp.obj):dff_main.cpp:(.text+0x0): first defined here

collect2.exe: error: ld returned 1 exit status

 

Please help me how to remove this error.

 

Regards

Sunil S.

 

 

 

 

[apfitch]

You need to separate your dff.cpp into two files, dff.h and dff.cpp. Put the class in dff.h, and put the function func() in dff.cpp.

Change the main to include dff.h instead of dff.cpp,

 

Alan