Ladder signal", My own signal"

Ricardo,

There's a deliberate mistake in the transition statement in the code - I forgot to add vmin to the signal, so it's always referred to 0. I ran it with this netlist:

//
V1 (lad 0) ladder vmin=-60m vmax=60m maxcount=32 periodic=0 period=80n
R1 (lad 0) resistor r=1k

ahdl_include "ladder.va"
tran tran stop=5u

And it produces the attached picture (I set it to have 32 steps to make the steps more obvious).

Here's the fixed code:

`include "disciplines.vams"

module ladder (outp,outm);
output outp,outm;
electrical outp,outm;

// extent of the signal output
parameter real vmin=0;
parameter real vmax=2.56;
// number of steps in the "ladder"
parameter integer maxcount=256;
// is it periodic? Set to 0 if you want it to be one shot
parameter integer periodic=1;
// period of time between steps in the ladder
parameter real period=10n;
// rise, fall, and delay of each step
parameter real tr=0.1n;
parameter real tf=0.1n;
parameter real td=0;

// internal variables
real scale;
integer count;

analog begin
    @(initial_step) begin
	count=0;
	scale=(vmax-vmin)/(maxcount-1);
    end

    @(timer(period,period)) 
	if(periodic) count=(count+1)%maxcount;
	else count=min(count+1,maxcount-1);

    V(outp,outm) <+ transition(count*scale+vmin,td,tr,tf);
end

endmodule

Regards,

Andrew.

Ricardo,

There's a deliberate mistake in the transition statement in the code - I forgot to add vmin to the signal, so it's always referred to 0. I ran it with this netlist:

//
V1 (lad 0) ladder vmin=-60m vmax=60m maxcount=32 periodic=0 period=80n
R1 (lad 0) resistor r=1k

ahdl_include "ladder.va"
tran tran stop=5u

And it produces the attached picture (I set it to have 32 steps to make the steps more obvious).

Here's the fixed code:

`include "disciplines.vams"

module ladder (outp,outm);
output outp,outm;
electrical outp,outm;

// extent of the signal output
parameter real vmin=0;
parameter real vmax=2.56;
// number of steps in the "ladder"
parameter integer maxcount=256;
// is it periodic? Set to 0 if you want it to be one shot
parameter integer periodic=1;
// period of time between steps in the ladder
parameter real period=10n;
// rise, fall, and delay of each step
parameter real tr=0.1n;
parameter real tf=0.1n;
parameter real td=0;

// internal variables
real scale;
integer count;

analog begin
    @(initial_step) begin
	count=0;
	scale=(vmax-vmin)/(maxcount-1);
    end

    @(timer(period,period)) 
	if(periodic) count=(count+1)%maxcount;
	else count=min(count+1,maxcount-1);

    V(outp,outm) <+ transition(count*scale+vmin,td,tr,tf);
end

endmodule

Regards,

Andrew.