Post on 30-May-2017
CONTENTS
1)Study of Simulation using tools.
2)Design Entry and Simulation of Combinational Logic Circuits
a)Basic logic gates
b)Half adder and full adder
c)Half Subtractor and full Subtractor
d)8 bit adder
e)4 bit multiplier
f)Encoder and Decoder
g)Address Decoder
h)Multiplexer
3)Design Entry and Simulation of Sequential Logic Circuits
a)Flip-Flops
b)Counter
c)PRBS generator
d)Accumulator
4)Study of Synthesis tools
5)Place and Route and Back annotation for FPGAs
6)Schematic Entry and SPICE Simulation
a)CMOS Inverter
b)Universal Gate
c)Differential Amplifier
7)Layout of a CMOS Inverter
8)Design of a 10 bit number controlled oscillator
9)Automatic Layout Generation
VLSI DESIGN
VLSI LAB MANUAL
Page 5
ASIC DESIGN FLOW
ASIC FLOW
Fig 1: Waveform Editor - Initialize Timing Dialog Box
Expt. No : STUDY OF SIMULATION TOOLS
Date :
AIM:
To study the Simulation tools
THEORY:
Creating a Test Bench for Simulation:
In this section, you will create a test bench waveform containinginput stimulus you can use to simulate the counter module. This test bench waveform is a graphical view of a test bench. It is used with asimulator to verify that the counter design meets both behavioral andtiming design requirements. You will use the Waveform Editor to create atest bench waveform (TBW) file.
1.Select the counter HDL file in the Sources in Project window.
2.Create a new source by selecting Project -New Source.
3.In the New Source window, select Test Bench Waveform asthe source type, and type test bench
in the File Name field.
4.Click Next.
5.The Source File dialog box shows that you are associating thetest bench
with the source file: counter.v Click Next.
6.Click Finish. You need to set initial values for your test benchwaveform in the Initialize Timing dialog box before the test bench waveform editing window opens.
7.Fill in the fields in the Initialize Timing dialog box usingthe information below:
Clock Time High:20 ns. Clock Time Low:20 ns. Input Setup Time:10 ns. Output Valid Delay:10 ns.
Initial Offset:0 ns
Global Signals:GSR (FPGA)
Leave the remaining fields with their default values.
8.Click OK to open the waveform editor. The blue shaded areas areassociated with each input signal and correspond to the Input Setup Timein the Initialize Timing dialog box. In this tutorial, the input transitionsoccur at the edge of the blue cells located under each rising edge of theCLOCK input.
Fig 2: Waveform Editor - Test Bench
9.In this design, the only stimulus that you will provide is on theDIRECTION port. Make the transitions as shown below for theDIRECTION port:
Click on the blue cell at approximately the 300 ns clock transition. Thesignal switches to high at this point.
Click on the blue cell at approximately the 1400 ns clocktransition. The signal switches to high again.
10.Select File -Save to save the waveform. In the Sources in Projectwindow, the TBW file is automatically added to your project.
11.Close the Waveform Editor window
VLSI LAB MANUAL
Simulating the Behavioral Model (ISE Simulator):
If you are using ISE Base or Foundation, you can simulate your design with theISE Simulator. If you wish to simulate your design with a ModelSim simulator,skip this section and proceed to the “Simulating the Behavioral Model(ModelSim)” section.
Fig 3: Simulator Processes for Test Bench
Fig 4: Behavioral Simulation in ISE Simulator
To run the integrated simulation processes in ISE:
1.Select the test bench waveform in the Sources in Project window. You cansee the Xilinx ISE Simulator processes in the Processes for Source window.
2.Double-click the Simulate Behavioral Model process. The ISE Simulatoropens and runs the simulation to the end of the test bench.
3.To see your simulation results, select the test bench tab and zoom in on thetransitions. You can use the zoom icons in the waveform view, or right clickand select a zoom command. The ISE window, including the waveform view.
4.Zoom in on the area between 300 ns and 900 ns to verify that thecounter is counting up and down as directed by the stimulus on theDIRECTION port.
5.Close the waveform view window. You have completed simulation of yourdesign using the ISE Simulator.
Simulating the Behavioral Model (ModelSim):
If you have a ModelSim simulator installed, you can simulate your design usingthe integrated ModelSim flow. You can run processes from within ISE whichlaunches the installed ModelSim simulator.
To run the integrated simulation processes in ISE:
1.Select the test bench in the Sources in Project window. You can seeModelSim Simulator processes in the Processes for Source window in Fig4
Fig 5: Simulator Processes for Test Bench
Fig 6: Behavioral Simulation in ModelSim
2.Double-click the Simulate Behavioral Model process. The ModelSimsimulator opens and runs your simulation to the end of the test bench. TheModelSim window, including the waveform, should look likeFig 6.To see your simulation results, view the Wave window.
1. Right-click in the Wave window and select a zoom command.
2.Zoom in on the area between 300 ns and 900 ns to verify that thecounter is counting up and down as directed by the stimulus on theDIRECTION port.
3.Close the ModelSim window
RESULT:
DESIGN ENTRY AND SIMULATION OF COMBINATIONAL LOGIC CIRCUITS
BASIC LOGIC GATES
Expt. No :
Date:
AIM:
To implement basic logic gates using Verilog HDL.
APPARATUS REQUIRED:
PC with Windows XP. XILINX, ModelSim software. FPGA kit. RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above Verilog code (usingModelSim or Xilinx) and verify
the output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM:
AND Gate: // Module Name: Andgate
module Andgate (i1, i2,out);
input i1, i2;
output out;
and (out,i1,i2);
endmodule
// Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1, i2;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Andgate uut1 (.i1(i1),.i2(i2),.out(out));
initial
begin
$display("\t\t\t\tAND Gate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b ",i1,i2,out);
#4 $display("\t\t--------------------------------------");
end
initial begin
i1=1'b0;
i2=1'b0;
#1 i2=1'b1;
#1 i1=1'b1;
i2=1'b0;
#1 i1=1'b1;
i2=1'b1;
#1$stop;
endendmodule
Symbol
TRUTH TABLE:
Simulated Waveform
PROGRAM
OR Gate:
// Module Name: Orgate
module Orgate (i1, i2,out);
input i1, i2;
output out;
or (out,i1,i2);
endmodule
// Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1, i2;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Orgate uut1 (.i1(i1),.i2(i2),.out(out));
initial
begin
$display("\t\t\t\tORGate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b ",i1,i2,out);
#4 $display("\t\t--------------------------------------");
end
initial
begin
i1=1'b0;
i2=1'b0;
#1 i2=1'b1;
#1 i1=1'b1;
i2=1'b0;
#1 i1=1'b1;
i2=1'b1;
#1$stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAMNOR Gate: // Module Name: Norgate
Module Norgate (i1, i2,out);
input i1, i2;
output out;
nor (out,i1,i2);
endmodule
// Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1, i2;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Norgate uut1 (.i1(i1),.i2(i2),.out(out));
initial
begin
$display("\t\t\t\tNORGate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b ",i1,i2,out);
#4 $display("\t\t--------------------------------------");
end
initial
begin
i1=1'b0; i2=1'b0; #1 i2=1'b1;
#1 i1=1'b1; i2=1'b0; #1 i1=1'b1; i2=1'b1;
#1$stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
Simulated Waveform
PROGRAM
XOR Gate: // Module Name:Xorgate
module Xorgate (i1, i2,out);
input i1, i2;
output out;
xor (out,i1,i2);
endmodule
//Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1, i2;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Xorgate uut1 (.i1(i1),.i2(i2),.out(out));
initial
begin
$display("\t\t\t\tXORGate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b ",i1,i2,out);
#4 $display("\t\t--------------------------------------");
end
initial
begin
i1=1'b0; i2=1'b0; #1 i2=1'b1;
#1 i1=1'b1; i2=1'b0; #1 i1=1'b1; i2=1'b1;
#1$stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAMXNOR Gate: // Module Name: Xnorgatemodule Xnorgate (i1, i2,out);
input i1, i2;
output out;xnor (out,i1,i2);
endmodule
//Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1, i2;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Xnorgate uut1 (.i1(i1),.i2(i2),.out(out));
initial begin$display("\t\t\t\tXNORGate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b ",i1,i2,out);
#4 $display("\t\t--------------------------------------");
end
initial
begini1=1'b0; i2=1'b0; #1 i2=1'b1;
#1 i1=1'b1; i2=1'b0; #1 i1=1'b1; i2=1'b1;
#1$stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAMNOT Gate: // Module Name: Notgatemodule Notgate (i1, out);
input i1;
output out;
not (out,i1);
endmodule
//Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1;
//Outputs
wire out;
// Instantiate the Unit Under Test (UUT)
Notgate uut1 (.i1(i1),. out(out));
initial
begin
$display("\t\t\t\tNOTGate");
$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Output");
$display("\t\t--------------------------------------");
$monitor("\t\t\t%b \t\t%b ",i1 ,out);
#4 $display("\t\t--------------------------------------");
end
initial begini1=1'b0;#1 i1=1'b1; #1 $stop;endendmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAM
Buffer:
// Module Name: Buffer
module Buffer (i1, out);
input i1;
output out;
buf (out,i1);
endmodule
// Module Name: Stimulus.v module
module stimulus;
//Inputs
reg i1;
//Outputs
wire out;// Instantiate the Unit Under Test (UUT)
Buffer uut1 (.i1(i1),. out(out));
initial
begin
$display("\t\t\t\tBuffer");$display("\t\t--------------------------------------");
$display("\t\tInput1\t\t Output");$display("\t\t--------------------------------------");
$monitor("\t\t\t%b \t\t%b ",i1 ,out);
#4 $display("\t\t--------------------------------------");
end
initial
begini1=1'b0;#1 i1=1'b1;
#1 $stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
RESULT:
Expt. No: HALF ADDER AND FULL ADDER
Date :
AIM:
To implement half adder and full adder using Verilog HDL.
APPARATUS REQUIRED:
PC with Windows XP XILINX, ModelSim software. FPGA kit RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above Verilog code (using ModelSimor Xilinx) and verify
the output waveform as obtained. Implement the above code in Spartan III using FPGA kit
PROGRAM:
Half Adder:
// Module Name: HalfAddr
module HalfAddr(sum, c_out, i1, i2);
output sum, c_out;
input i1;
input i2;
xor(sum,i1,i2);
and(c_out,i1,i2);
endmodule
//Module Name: Stimulus.v
module Stimulus_v;
// Inputs
reg i1,i2;
// Outputs
wire sum, c_out;
// Instantiate the Unit Under Test (UUT)
HalfAddr uut (.sum(sum),.c_out(c_out),.i1(i1),.i2(i2));
initial
begin
$display("\t\t\Half Adder");
$display("\t\tInput1\t\t Input2\t\t Carry\t\t Sum");
$display("\t\t----------------------------------------");
$monitor(“\%b\t\t%b\t\t%b\t\t”,i1,i2,c_out,sum);
$display("\t\t ---------------------------------------“);
end
initial
begin
i1=1'b0; i2=1'b0; #1 i2=1'b1;#1 i1=1'b1; i2=1'b0;
#1 i1=1'b1; i2=1'b1;
#1 $stop;
end
endmodule
SYMBOL:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAM
Full Adder:
// Module Name: FullAddr
module FullAddr(i1, i2, c_in, c_out, sum);
input i1, i2, c_in;
output c_out, sum;
wire s1,c1,c2;
xor n1(s1,i1,i2);
and n2(c1,i1,i2);
xor n3(sum,s1,c_in);
and n4(c2,s1,c_in);
or n5(c_out,c1,c2);
endmodule
// Module Name: Stimulus.v
module Stimulus_v;
// Inputsreg i1 , i2 , c_in;
// Outputswire c_out, sum;
// Instantiate the Unit Under Test (UUT)
FullAddr uut (.i1(i1),.i2(i2),.c_in(c_in),.c_out(c_out),.sum(sum));
initial
begin
$display("\t\t\t\t\t\tFull Adder");
$display("\t\t----------------------------------------------------------------");
$display("\t\ti1\t\ti2\t\tC_in\t\t\tC_out\t\tSum");
$display("\t\t----------------------------------------------------------------");
$monitor(" t\t%b\t\t%b\t\t%b\t\t\t%b\t\t%b",i1,i2,c_in,c_out,sum);
#9 $display("\t\t-------------------------------------------------------------------");
end
initial
begin
#1i1 = 0;i2 = 0;c_in = 0;
#1 i1 = 0;i2 = 0;c_in = 0;
#1 i1 = 0;i2 = 0;c_in = 1;
#1 i1 = 0;i2 = 1;c_in = 0;
#1 i1 = 0;i2 = 1;c_in = 1;
#1 i1 = 1;i2 = 0;c_in = 0;
#1 i1 = 1;i2 = 0;c_in = 1;
#1 i1 = 1;i2 = 1;c_in = 0;
#1 i1 = 1;i2 = 1;c_in = 1;
#2 $stop;
end
endmodule
LOGIC DIAGRAM:
TRUTH TABLE:
SIMULATED WAVEFORM:
RESULT:
Expt. No: HALF SUBTRACTOR & FULL SUBTRACTOR
Date :
AIM:
To implement half subtractor and full subtractor using Verilog HDL.
APPARATUS REQUIRED:
PC with Windows XP XILINX, ModelSim software. FPGA kit RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above verilog code (using ModelSim orXilinx) and verify the
output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM:
Half Subtractor: // Module Name: HalfSub
module HalfSub(i0, i1, bor, dif);
input i0, i1;
output bor,dif;
wire i0n;not(i0n,i0);xor(dif,i0,i1);
and(bor,i0n,i1);
endmodule
// ModuleName:Stimulus.v
module Stimulus_v;
// Inputs
reg i0, i1;
//Outputs
wire bor; wire dif;
//Instantiate the Unit Under Test (UUT)
HalfSub uut (.i0(i0),.i1(i1),.bor(bor),.dif(dif));
initial
begin
$display("\t\t\t\t\tHalf Subtractor");
$display("\t\t----------------------------------------------------------");
$display("\t\tInput1\t\t Input2\t\t Borrow\t\t Difference");
$display("\t\t----------------------------------------------------------");
$monitor("\t\t\t%b\t\t%b\t\t%b\t\t%b",i0,i1,bor,dif);
#4 $display("\t\t-----------------------------------------------------------");
end
initial
begin
i0=1'b0;
i1=1'b0;
#1 i1=1'b1;
#1 i0=1'b1;
i1=1'b0;
#1 i0=1'b1;
i1=1'b1;
#1$stop;
end
endmodule
LOGIC DIAGRAM:
TRUTH TABLE:
SIMULATED WAVEFORM
PROGRAM
Full Subtractor:
// Module Name: FullSub
module FullSub(b_in, i1, i0, b_out, dif);
input b_in;
input i1, i0;
output b_out,dif;
assign {b_out,dif}=i0-i1-b_in;
endmodule
// Module Name: Stimulus.v
module Stimulus_v;
// Inputsreg b_in, i1,i0;/
/ Outputs
wire b_out;
wire dif;
// Instantiate the Unit Under Test (UUT)
FullSub uut (.b_in(b_in),.i1(i1),.i0(i0),.b_out(b_out),.dif(dif));
initial
begin
$display("\t\t\t\t\t\tFull Subtractor");
$display("\t\t-------------------------------------------------------------------------");
$display("\t\tB_in\t\tI1\t\ti0\t\t\tB_out\t\tDifference");
$display("\t\t-------------------------------------------------------------------------");
$monitor("\t\t%b\t\t%b\t\t%b\t\t\t %b\t\t\t %b",b_in,i1,i0,b_out,dif);
#9 $display("\t\t-------------------------------------------------------------------------");
end
initial
begin
// Initialize Inputs
b_in = 0;i1 = 0;i0 = 0;
#1 b_in = 0;i1 = 0;i0 = 0;
#1 b_in = 0;i1 = 0;i0 = 1;
#1 b_in = 0;i1 = 1;i0 = 0;
#1 b_in = 0;i1 = 1;i0 = 1;
#1 b_in = 1;i1 = 0;i0 = 0;
#1 b_in = 1;i1 = 0;i0 = 1;
#1 b_in = 1;i1 = 1;i0 = 0;
#1 b_in = 1;i1 = 1;i0 = 1;
#2 $stop;
end
endmodule
LOGIC DIAGRAM:
TRUTH TABLE:
SIMULATED WAVEFORM:
RESULT:
Expt. No: 4BIT MULTIPLIER
Date :
AIM:
To implement four bit multiplier using Verilog.
APPARATUS REQUIRED:
PC with Windows XP XILINX, ModelSim software FPGA kit RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above verilog code (usingModelSim or Xilinx) and verify the
output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM
MULTIPLIER
module multi(a,b, c);
input [3:0] a,b;
output [7:0] c;
assign c = a * b;
endmodule
STIMULUS
module testbenchmulti ;
//inputsreg [3:0] a,b;
//outputswire [7:0] c;
multi multipl(.c(c),.a(a),.b(b));
initial begina=4'b0; b=4'b0;
//wait 100ns for global reset to finish
#100; a=4'd3; b=4'd4;
#100; a=4'd3; b=4'd5;
#100; a=4'd2; b=4'd4;
end
endmodule
BLOCK DIAGRAM:
SIMULATED WAVEFORM:
RESULT:
Expt. No: 8 BIT ADDER
Date :
AIM:
To implement the 8-bit adder using Verilog.
APPARATUS REQUIRED:
PC with Windows XP XILINX, ModelSim software FPGA kit RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above verilog code (using ModelSimor Xilinx) and verify the Implement the above code in Spartan III using FPGA kit.
PROGRAM
8 BIT ADDER
module adder(a,b, s,c);
input [7:0] a,b;
output [7:0] s,c;
assign {c,s} = a + b;
endmodule
STIMULUS:
module testbenadder;
//Inputs
reg [7:0] a,b;
//outputs
wire [7:0] s;
wire c;
adder add(.s(s),.c(c),.a(a),.b(b));
initial
begin
//initialize input
a=8'd0; b=8'd0;
//wait 100ns for global reset to finish
#100; a=8'd1; b=8'd0;
#100; a=8'd9; b=8'd5;
#100; a=8'd5; b=8'd7;
end
endmodule
BLOCK DIAGRAM:
RESULT:
Expt No: IMPLEMENTATION OF 4x2 ENCODER AND
Date: 2x4 DECODER
AIM:
To implement 4x2 Encoder and 2 x 4 Decoder Verilog HDL.
APPARATUS REQUIRED:
PC with Windows XP. XILINX, ModelSim software. FPGA kit. RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above verilog code (usingModelSim or Xilinx) and verify the
output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM:
Encoder: // Module Name: Encd2to4
module Encd2to4(i0, i1, i2, i3, out0, out1);
input i0,i1, i2, i3;
output out0, out1;
reg out0,out1;
always@(i0,i1,i2,i3)
case({i0,i1,i2,i3})
4'b1000:{out0,out1}=2'b00;
4'b0100:{out0,out1}=2'b01;
4'b0010:{out0,out1}=2'b10;
4'b0001:{out0,out1}=2'b11;
default:
$display("Invalid");
endcase
endmodule
// Module Name: Stimulus.v
module Stimulus_v;//
Inputsreg i0, i1, i2, i3;//
Outputswire out0, out1;
//Instantiate the Unit Under Test (UUT)
Encd2to4 uut(.i0(i0),.i1(i1),.i2(i2),.i3(i3),.out0(out0),.out1(out1));
initial
begin
$display("\t\t 4to2 Encoder");$display("\t\t------------------------------");
$display("\t\tInput\t\t\tOutput");
$display("\t\t------------------------------");
$monitor("\t\t%B%B%B%B\t\t\t %B%B",i0,i1,i2,i3,out0,out1);
#4 $display("\t\t-------------------------------");
end
initial
begin
i0=1; i1=0; i2=0; i3=0;
#1 i0=0; i1=1; i2=0; i3=0;
#1 i0=0; i1=0; i2=1; i3=0;
#1 i0=0; i1=0; i2=0; i3=1;
#1 $stop;
end
endmodule
BLOCK DIAGRAM:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAMDecoder:
// Module Name: Decd2to4
module Decd2to4(i0, i1, out0, out1, out2, out3);
input i0, i1;
output out0, out1, out2, out3;
regout0,out1,out2,out3;
always@(i0,i1)
case({i0,i1})
2'b00:{out0,out1,out2,out3}=4'b1000;
2'b01:{out0,out1,out2,out3}=4'b0100;
2'b10:{out0,out1,out2,out3}=4'b0010;
2'b11:{out0,out1,out2,out3}=4'b0001;
default:$display("Invalid");
endcase
endmodule
/ Module Name: Stimulus.v
module Stimulus_v;
// Inputs
reg i0, i1;
//Outputs
wire out0, out1, out2, out3;
//Instantiate the Unit Under Test (UUT)
Decd2to4 uut (.i0(i0),.i1(i1),.out0(out0),.out1(out1),.out2(out2),.out3(out3));
initial
begin
$display(“\t\t 2to4 Decoder”);
$display(“\t\t --------------------------”);
$display(“\t\t Input \t\t Output”);
$display(“\t\t --------------------------”);
$monitor(“\t\t %b%b\t\t\t %b%b%b %b”,i0,i1,out0,out1,out2,out3);
#4 $display(“\t\t --------------------------”);
end
initial
begin
i0=0;i1=0;
#1 i0=0;i1=1;
#1 i0=1;i1=0;
#1 i0=1;i1=1;
#1 $stop;
end
endmodule
TRUTH TABLE:
SIMULATED WAVEFORM:
RESULT:
Expt. No: MULTIPLEXER & DEMULTIPLEXER
Date :
AIM:
To implement Multiplexer & Demultiplexer using Verilog HDL.
APPARATUS REQUIRED:
PC with Windows XP. XILINX, ModelSim software. FPGA kit. RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above verilog code (usingModelSim or Xilinx) and verify the
output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM:
Multiplexer: // Module Name: Mux4to1
module Mux4to1(i0, i1, i2, i3, s0, s1, out);
input i0, i1, i2, i3, s0, s1;
output out;
wire s1n,s0n;
wire y0,y1,y2,y3;
not (s1n,s1);
not (s0n,s0);and (y0,i0,s1n,s0n);
and (y1,i1,s1n,s0);
and (y2,i2,s1,s0n);
and (y3,i3,s1,s0);
or (out,y0,y1,y2,y3);
endmodule
/ Module Name: Stimulus.v
module Stimulus_v;
// Inputs
reg i0, i1, i2,,i3, s0, s1;
//Outputs
wire out;
Instantiate the Unit Under Test (UUT)
Mux4to1 uut (.i0(i0),.i1(i1),.i2(i2),.i3(i3),.s0(s0),.s1(s1),.out(out));
initial
begin
$display(“\t\t\t4to1 Multiplexer”);
$display(“\t\t-------------------------“);
#1 $display(“\t\t\t Input=%b%b%b%b”,i0,i1,i2,i3);
$display(“\t\t----------------------------------“);
$display(“\t\tSelector \t\t\t\t Output”);
$display(“\t\t----------------------------------“);
$monitor(“\t\t{%b,%b}\t\t\t\t%b”,s0,s1,out);
#4 $display(“\t\t-----------------------------------------------“);
end
initial
begin
i0=1; i1=0; i2=1; i3=1;
#1 s0=0; s1=0;
#1 s0=1; s1=0;
#1 s0=0; s1=1;
#1 s0=1; s1=1;
#1 $stop;
end
endmodule
LOGIC DIAGRAM:
TRUTH TABLE:
SIMULATED WAVEFORM:
PROGRAM
Demultiplexer:
// Module Name: Dux1to4
module Dux1to4(in, s0, s1, out0, out1, out2, out3);
input in, s0, s1;output out0, out1, out2,out3;
wire s0n,s1n;
not(s0n,s0);
not(s1n,s1);
and (out0,in,s1n,s0n);
and (out1,in,s1n,s0);
and (out2,in,s1,s0n);
and (out3,in,s1,s0);
endmodule
// Module Name: Stimulus.v
module Stimulus_v;//Inputsreg in, s0, s1;//
Outputswire out0, out1, out2, out3;//
Instantiate the Unit Under Test (UUT)
Dux1to4 uut (.in(in),.s0(s0),.s1(s1),.out0(out0),.out1(out1),.out2(out2),.out3(out3));
initial
begin
$display("\t\t 1to4 Demultiplexer");
$display("\t\t------------------------------------");
#1 $display("\t\t\t\tInput=%b",in);
$display("\t\t------------------------------------");
$display("\t\tStatus\t\t\t\tOutput");
$display("\t\t------------------------------------");
$monitor("\t\t{%b,%b}\t\t\t\t%b%b%b%b",s1,s0,out0,out1,out2,out3);
#4 $display("\t\t------------------------------------");
end
initial
begin
in=1;#1 s1=0;s0=0;
#1 s1=0;s0=1;
#1 s1=1;s0=0;
#1 s1=1;s0=1;
#1 $stop;
end
endmodule
TRUTH TABLE:
DEMULTIPLEXER
LOGIC DIAGRAM:
SIMULATED WAVEFORM:
RESULT:
Expt. No: IMPLEMENTATION OF COUNTERS
Date:
AIM:
To implement Counters using Verilog HDL
APPARATUS REQUIRED:
PC with Windows XP. XILINX, ModelSim software. FPGA kit. RS 232 cable.
PROCEDURE:
Write and draw the Digital logic system. Write the Verilog code for above system. Enter the Verilog code in Xilinx software. Check the syntax and simulate the above Verilog code (usingModelSim or Xilinx) and verify
the output waveform as obtained. Implement the above code in Spartan III using FPGA kit.
PROGRAM:
2- Bit Counter:
// Module Name: Count2Bit
module Count2Bit(Clock, Clear, out);
input Clock, Clear;
output [1:0] out;
reg [1:0]out;
always@(posedge Clock, negedge Clear)
if((~Clear) || (out>=4))
out=2'b00;
elseout=out+1;
endmodule
// Module Name: Stimulus.v
module Stimulus_v;
//Inputs
reg Clock, Clear;
//Outputs
wire [1:0] out;
//Instantiate the Unit Under Test (UUT)
Count2Bit uut (.Clock(Clock),.Clear(Clear),.out(out));
initial
begin
$display("\t\t\t 2 Bit Counter");
$display("\t\t----------------------------------------");
$display("\t\tClock\t\tClear\t\tOutput[2]");
$display("\t\t----------------------------------------");
$monitor("\t\t %b\t\t %b \t\t %b ",Clock,Clear,out);
#28 $display("\t\t----------------------------------------");
end
always#1 Clock=~Clock;
initial
begin
Clock=0;
Clear=0;
#10 Clear=1;
#18 Clear=0;
#2 $stop;
end
endmodule
LOGIC DIAGRAM:
SIMULATED WAVEFORM: