2’s complement 4-bit saturator
DESCRIPTION
2’s Complement 4-Bit Saturator. Lecture L4.6. Equality Detector. XNOR. X Y Z 0 0 1 0 1 0 1 0 0 1 1 1. X. Z. Y. Z = !(X $ Y). Z = 1 if A=B=C. 4 x 1. MUX. s1. s0. Y. 0 0 C0 0 1 C1 1 0 C2 1 1 C3. Multiplexers. C0. C1. Y. C2. C3. s1. s0. - PowerPoint PPT PresentationTRANSCRIPT
2’s Complement 4-Bit Saturator
Lecture L4.6
Equality Detector
XNOR
X
YZ
Z = !(X $ Y)
X Y Z0 0 10 1 01 0 01 1 1
Z = 1 if A=B=C
A
B
C
Z
A=B
B=C
A=B=C
Multiplexers
Y 4 x 1 MUX
s0s1
C0
C1
C2
C3
Y s1 s0
0 0 C00 1 C11 0 C21 1 C3
Multiplexers
Y
4 x 1 MUX
s0s1
C0
C1
C2
C3
Y s1 s0
0 0 C00 1 C11 0 C21 1 C3
0 0
A multiplexer is adigital switch
Multiplexers
Y
4 x 1 MUX
s0s1
C0
C1
C2
C3
Y s1 s0
0 0 C00 1 C11 0 C21 1 C3
0 1
Multiplexers
Y
4 x 1 MUX
s0s1
C0
C1
C2
C3
Y s1 s0
0 0 C00 1 C11 0 C21 1 C3
1 0
Multiplexers
Y
4 x 1 MUX
s0s1
C0
C1
C2
C3
Y s1 s0
0 0 C00 1 C11 0 C21 1 C3
1 1
A 2 x 1 MUX
2 x 1MUX
A
B
Z
s0
s0 Z
0 A
1 B
Z = A & !s0 # B & s0
Y S
0 A 1 B
ProblemHow would you make a
Quad 2-to-1 MUX?
S
[A3..A0][B3..B0]
[Y3..Y0] Quad2-to-1MUX
NASA Tech Briefs November 2001
X0X1X2
X3
X4
X5
c0
c1
Y0Y1Y2Y3
A
B
X = 111111Y = 1111
X = 000101Y = 0101
X = 011101Y = 0111
X = 110101Y = 1000
// Title: 2s-complement 4-bit Saturator// Author: R. E. Haskell// Ref: NASA Tech Briefs, Nov. 2001// Description: 4-bit output Y = // -8 if 6-bit input X is <= -8// +7 if 6-bit input X is >= +7// X otherwise
MODULE sat64INTERFACE ([X5..X0] -> [Y3..Y0]);TITLE '2s complement 4-bit saturator'// Author: R. E. Haskell
ABEL
DECLARATIONS" Input Pins "X5..X0 PIN ISTYPE 'com';X = [X5..X0]; " 6-bit input" Output Pins "Y3..Y0 PIN ISTYPE 'com';Y = [Y3..Y0]; " 4-bit output
"DefinitionsA = [X5,!X5,!X5,!X5];B = [X3,X2,X1,X0];c0 = !(X3 $ X4);c1 = !(X4 $ X5);s = c0 & c1;
EQUATIONSY = !s & A # s & B;
END
X0X1X2
X3
X4
X5
c0
c1
Y0Y1Y2Y3
A
B
Top-level Design
[a,b,c,d,e,f,g]sat
sat64[DataIn]76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
// Title: Absolute value function// Author: R. E. Haskell// Input: Y = 4-bit signed number (-8 to +7)// Output: Z = magnitude of input number (0 to 8)
MODULE absvalinterface([Y3..Y0] -> [Z3..Z0]);
DECLARATIONS
" INPUT PINS "
Y3..Y0 PIN; Y = [Y3..Y0]; " 4-bit input
" OUTPUT PINS "
Z3..Z0 PIN ISTYPE 'com'; Z = [Z3..Z0]; " 4-bit output
DECLARATIONS" INPUT PINS "Y3..Y0 PIN; Y = [Y3..Y0]; " 4-bit input
" OUTPUT PINS "Z3..Z0 PIN ISTYPE 'com'; Z = [Z3..Z0]; " 4-bit output
EQUATIONSwhen (Y == 0) then Z = ^b0000;when (Y == 1) then Z = ^b0001;when (Y == 2) then Z = ^b0010;when (Y == 3) then Z = ^b0011;when (Y == 4) then Z = ^b0100;when (Y == 5) then Z = ^b0101;when (Y == 6) then Z = ^b0110;when (Y == 7) then Z = ^b0111;when (Y == 8) then Z = ^b1000;when (Y == 9) then Z = ^b0111;when (Y == ^h0A) then Z = ^b0110;when (Y == ^h0B) then Z = ^b0101;when (Y == ^h0C) then Z = ^b0100;when (Y == ^h0D) then Z = ^b0011;when (Y == ^h0E) then Z = ^b0010;when (Y == ^h0F) then Z = ^b0001;
END absval
Top-level Design
[a,b,c,d,e,f,g]sat
sat64[DataIn]76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
// Title : 2's Complement 4-Bit Saturator// Author : R. E. Haskell// Description : 7-segment displays show the signed output// of the 2's complement 4-bit saturator
MODULE sat4bit
DECLARATIONSsat64 INTERFACE ([X5..X0] -> [Y3..Y0]);sat FUNCTIONAL_BLOCK sat64;
absval INTERFACE ([Y3..Y0] -> [Z3..Z0]);abs FUNCTIONAL_BLOCK absval;
hex7seg INTERFACE ([D3..D0] -> [a,b,c,d,e,f,g]);d7R FUNCTIONAL_BLOCK hex7seg;
" INPUT PINS "SW5..SW0 PIN 6,5,4,3,2,1; " S6, Switches 3,4; S7, Switches 1-4SW = [SW5..SW0];
" OUTPUT PINS "LEDR3..LEDR0 PIN 40,41,43,44 ISTYPE 'com'; " LEDs 13-16LEDR = [LEDR3..LEDR0];
[a,b,c,d,e,f,g] PIN 15,18,23,21,19,14,17 ISTYPE 'com';Rsegments = [a,b,c,d,e,f,g]; " Rightmost 7-segment digit
minus PIN 66 ISTYPE 'com'; " segment g of left 7seg display
EQUATIONSsat.[X5..X0] = SW;LEDR = sat.[Y3..Y0];abs.[Y3..Y0] = sat.[Y3..Y0];d7R.[D3..D0] = abs.[Z3..Z0];Rsegments = d7R.[a,b,c,d,e,f,g];minus = sat.Y3;
END
[a,b,c,d,e,f,g]satsat64[DataIn]
76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
Verilog// Title: 2s-complement 4-bit Saturator// Author: R. E. Haskell// Ref: NASA Tech Briefs, Nov. 2001// Description: 4-bit output Y = // -8 if 6-bit input X is <= -8// +7 if 6-bit input X is >= +7// X otherwise
module sat64(X,Y);input [5:0] X;output [3:0] Y;
module sat64(X,Y);input [5:0] X;output [3:0] Y;
wire [3:0] Y;wire c0, c1, s;wire [3:0] A;wire [3:0] B;
assign A[3] = X[5];assign A[2:0] = {~X[5],~X[5],~X[5]};assign B = {X[3],X[2],X[1],X[0]};
assign c1 = X[3] ~^ X[4];assign c0 = X[4] ~^ X[5];assign s = c0 & c1;
assign Y = {4{~s}} & A | {4{s}} & B;
endmodule
X0X1X2
X3
X4
X5
c0
c1
Y0Y1Y2Y3
A
B
Top-level Design
[a,b,c,d,e,f,g]sat
sat64[DataIn]76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
// Title: Absolute value function// Author: R. E. Haskell// Input: Y = 4-bit signed number (-8 to +7)// Output: Z = magnitude of input number (0 to 8)
module absval(Y,Z); input [3:0] Y; output [3:0] Z;
reg [3:0] Z;
module absval(Y,Z); input [3:0] Y; output [3:0] Z;
reg [3:0] Z;
always @(Y) case(Y)
0: Z = 4'b0000; 1: Z = 4'b0001; 2: Z = 4'b0010; 3: Z = 4'b0011; 4: Z = 4'b0100; 5: Z = 4'b0101; 6: Z = 4'b0110; 7: Z = 4'b0111; 8: Z = 4'b1000; 9: Z = 4'b0111; 'hA: Z = 4'b0110; 'hb: Z = 4'b0101; 'hC: Z = 4'b0100; 'hd: Z = 4'b0011; 'hE: Z = 4'b0010; 'hF: Z = 4'b0001;
default: Z = 4'b0000; // 0 endcase
endmodule
Top-level Design
[a,b,c,d,e,f,g]sat
sat64[DataIn]76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
// Title : 2's Complement 4-Bit Saturator// Author : R. E. Haskell// Description : 7-segment displays show the signed output // of the 2's complement 4-bit saturator
module sat4bit(SW,LEDR,LEDG,AtoG,gg); input [5:0] SW;
output [3:0] LEDR;output [5:0]LEDG;
output [6:0] AtoG; output gg;
[a,b,c,d,e,f,g]satsat64[DataIn]
76
[LED13..LED16]
absabsval
d7Rhex7seg
44
1
[gg]
4
module sat4bit(SW,LEDR,LEDG,AtoG,gg); input [5:0] SW;
output [3:0] LEDR;output [5:0]LEDG;
output [6:0] AtoG; output gg;
wire [6:0] AtoG; wire [3:0] LEDR;
wire [5:0] LEDG;wire gg;wire [3:0] Y;wire [3:0] Z;
assign LEDR = Y;assign LEDG = SW;assign gg = Y[3];
sat64 sat(.X(SW),.Y(Y));hex7seg d7R(.D(Z),.AtoG(AtoG));absval abs(.Y(Y),.Z(Z));
endmodule