Half Adder & Full Adder

Half adder

CHIP HalfAdder {

IN a, b;

OUT sum, // LSB of a + b

carry; // MSB of a + b

PARTS:

Xor(a=a, b=b, out=sum);
And(a=a, b=b, out=carry);
}


Full Adder

CHIP FullAdder {
IN a, b, c;

OUT sum, // LSB of a + b + c

carry; // MSB of a + b + c

PARTS:

HalfAdder(a=c, b=b, sum=sum1, carry=carry1);
HalfAdder(a=a, b=sum1, sum=sum);
And(a=a, b=sum1, out=out1);
Or(a=carry1, b=out1, out=carry);

}


Adder 16 bit

CHIP Add16 {


IN a[16], b[16];

OUT out[16];


PARTS:

HalfAdder(a= a[0], b=b[0], sum= out[0], carry=carry1);
FullAdder(a= a[1], b=b[1], c =carry1, sum = out[1], carry = carry2);
FullAdder(a= a[2], b=b[2], c =carry2, sum = out[2], carry = carry3);
FullAdder(a= a[3], b=b[3], c =carry3, sum = out[3], carry = carry4);
FullAdder(a= a[4], b=b[4], c =carry4, sum = out[4], carry = carry5);
FullAdder(a= a[5], b=b[5], c =carry5, sum = out[5], carry = carry6);
FullAdder(a= a[6], b=b[6], c =carry6, sum = out[6], carry = carry7);
FullAdder(a= a[7], b=b[7], c =carry7, sum = out[7], carry = carry8);
FullAdder(a= a[8], b=b[8], c =carry8, sum = out[8], carry = carry9);
FullAdder(a= a[9], b=b[9], c =carry9, sum = out[9], carry = carry10);
FullAdder(a= a[10], b=b[10], c =carry10, sum = out[10], carry = carry11);
FullAdder(a= a[11], b=b[11], c =carry11, sum = out[11], carry = carry12);
FullAdder(a= a[12], b=b[12], c =carry12, sum = out[12], carry = carry13);
FullAdder(a= a[13], b=b[13], c =carry13, sum = out[13], carry = carry14);
FullAdder(a= a[14], b=b[14], c =carry14, sum = out[14], carry = carry15);
FullAdder(a= a[15], b=b[15], c =carry15, sum = out[15], carry = carry16);

}

Increment 16bit

CHIP Inc16 {

IN in[16];
OUT out[16];

PARTS:
Add16(a[0..15] = in[0..15], b[1..15] = false, b[0] = true, out = out);
}

All chips in the CHAPTER 1

Finally completed the Chapter1 project. Solutions are there in the below link

Chapter.1 solutions

CHAPTER 1

Chip Design is as interesting as Programming. For building OR gate from NAND,we need to remember the basic theorems in Digital electronics.De_Morgan laws



DMUX


MUX





DMux4Way



CHIP DMux4Way {

IN in, sel[2];

OUT a, b, c, d;

PARTS:


DMux(in=in, sel=sel[1], a=mux1, b=mux2);

DMux(in=mux1, sel=sel[0], a=a, b=b);

DMux(in=mux2, sel=sel[0], a=c, b=d);

}




DMux8Way

CHIP DMux8Way {

IN in, sel[3];

OUT a, b, c, d, e, f, g, h;

PARTS:

DMux(in=in, sel=sel[2], a=mux1, b=mux2);
DMux4Way(in=mux1, sel[0]=sel[0], sel[1]=sel[1], a=a,b=b,c=c,d=d);
DMux4Way(in=mux2, sel[0]=sel[0], sel[1]=sel[1], a=e,b=f,c=g,d=h);

}