Asif,
There is no fundamental reason why you cannot use a signal of any type
as a "clock" i.e. a periodic signal used to trigger processes.
I suspect you are asking how to generate such a signal from an sc_clock
channel. You can do this inside a process that is sensitive to the
clock.
e.g
SC_MODULE(clock_gen) {
//ports
sc_out<sc_logic> clk;
//internal clock
sc_clock i_clk;
//processes
void do_proc() {
if i_clk.read() clk.write(sc_logic_1);
else clk.write(sc_logic_0); }
SC_CTOR(clock_gen):i_clk("ICLK", 10, SC_NS)
{
SC_METHOD(do_proc);
sensitive << i_clk;
}
};
Your next problem is how to use this clock to trigger other modules.
Unfortunately you cannot say
sensitive_pos << clk;
since this only works with bool signal ports so the processes must be
triggered by any clock transition.
If you look at the sc_signal<sc_logic> class (in sc_signal.h> you may
notice functions to detect positive and negative edges. Unfortunately,
these are not part of the interface class used by sc_in/sc_out so you
cannot use them on your clock port.
Here is a possible solution:
SC_MODULE(test) {
sc_in<sc_logic> clk;
void do_proc1() {
while (true)
{
cout << "Positive clock at " << sc_time_stamp() << endl;
do wait(); while ( Clock.read() != sc_logic_1);
}
}
void do_proc2()
{
if (Clock.read()== '0' ) {
cout << "Negative clock edge at " << sc_time_stamp() << endl;
}
SC_CTOR(test)
{
SC_THREAD(do_proc1);
sensitive << clk;
SC_METHOD(do_proc2);
sensitive << clk;
}
};
As you can see, it is much easier to use sc_clk and associated ports
unless you have a good reason not to. If you have a common requirement
to use your own clock types, I suggest you create your own clock channel
- look at how the sc_clock hierarchical channel and its interfaces are
written.
Dave
In message <20020404115649.14490.qmail@xxxxxxxxxxxxxxxxxxxxxxx>, Asif CN
<asifcn@xxxxxxxxx> writes
hi all,
can we declare "clock" as <sc_logic> data type???
ie, sc_in<sc_logic> clk;
and then how we will generate a clock and port map to the
<sc_logic> clock in main module???
please comment/advice on this.....
thanks a lot
Asif
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