Chapter 3

Sequential Logic

DFF

Data Flip-Flop(primitive):延遲觸發器（或數據觸發器）。是一個基本的狀態保持裝置，是已經寫好的程式因此我們可以直接使用，存儲設備是由在相同的一個時鐘信號前提下許多的flip－flops組成的。我們在使用時可以存儲下來輸出的值。

Bit

1-bit register。通過load（t－1）的值決定out（t）是否改變。

CHIP Bit {
    IN in, load;
    OUT out;

    PARTS:
    // Put your code here:
    DFF(in = muxout,out = ffout,out = out);
    Mux(a = ffout,b = in,sel = load,out = muxout);
}

Register

16-bit register.

CHIP Register {
    IN in[16], load;
    OUT out[16];

    PARTS:
    // Put your code here:
    Bit(in = in[0],load = load,out = out[0]);
    Bit(in = in[1],load = load,out = out[1]);
    Bit(in = in[2],load = load,out = out[2]);
    Bit(in = in[3],load = load,out = out[3]);
    Bit(in = in[4],load = load,out = out[4]);
    Bit(in = in[5],load = load,out = out[5]);
    Bit(in = in[6],load = load,out = out[6]);
    Bit(in = in[7],load = load,out = out[7]);
    Bit(in = in[8],load = load,out = out[8]);
    Bit(in = in[9],load = load,out = out[9]);
    Bit(in = in[10],load = load,out = out[10]);
    Bit(in = in[11],load = load,out = out[11]);
    Bit(in = in[12],load = load,out = out[12]);
    Bit(in = in[13],load = load,out = out[13]);
    Bit(in = in[14],load = load,out = out[14]);
    Bit(in = in[15],load = load,out = out[15]);
}

RAM8

16-bit/8-register memory.

CHIP RAM8 {
    IN in[16], load, address[3];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = load,sel = address,a = a,b = b,c = c,d = d,e = e,f = f,g = g,h = h);
    Register(in = in,load = a,out = outa);
    Register(in = in,load = b,out = outb);
    Register(in = in,load = c,out = outc);
    Register(in = in,load = d,out = outd);
    Register(in = in,load = e,out = oute);
    Register(in = in,load = f,out = outf);
    Register(in = in,load = g,out = outg);
    Register(in = in,load = h,out = outh);

    Mux8Way16(a = outa,b = outb,c = outc,d = outd,e = oute,f = outf,g = outg,h = outh,sel = address,out = out);
}

RAM64

16-bit/64-register memory.

CHIP RAM64 {
    IN in[16], load, address[6];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = load,sel = address[3..5],a = a,b = b,c = c,d = d,e = e,f = f,g = g,h = h);

    RAM8(in = in,load = a,address = address[0..2],out = outa);
    RAM8(in = in,load = b,address = address[0..2],out = outb);
    RAM8(in = in,load = c,address = address[0..2],out = outc);
    RAM8(in = in,load = d,address = address[0..2],out = outd);
    RAM8(in = in,load = e,address = address[0..2],out = oute);
    RAM8(in = in,load = f,address = address[0..2],out = outf);
    RAM8(in = in,load = g,address = address[0..2],out = outg);
    RAM8(in = in,load = h,address = address[0..2],out = outh);

    Mux8Way16(a = outa,b = outb,c = outc,d = outd,e = oute,f = outf,g = outg,h = outh,sel = address[3..5],out = out);
}

RAM512

16-bit/512-register memory.

CHIP RAM512 {
    IN in[16], load, address[9];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = load,sel = address[6..8],a = a,b = b,c = c,d = d,e = e,f = f,g = g,h = h);

    RAM64(in = in,load = a,address = address[0..5],out = outa);
    RAM64(in = in,load = b,address = address[0..5],out = outb);
    RAM64(in = in,load = c,address = address[0..5],out = outc);
    RAM64(in = in,load = d,address = address[0..5],out = outd);
    RAM64(in = in,load = e,address = address[0..5],out = oute);
    RAM64(in = in,load = f,address = address[0..5],out = outf);
    RAM64(in = in,load = g,address = address[0..5],out = outg);
    RAM64(in = in,load = h,address = address[0..5],out = outh);

    Mux8Way16(a = outa,b = outb,c = outc,d = outd,e = oute,f = outf,g = outg,h = outh,sel = address[6..8],out = out);
}

RAM4K

16-bit/4096-register memory

CHIP RAM4K {
    IN in[16], load, address[12];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux8Way(in = load,sel = address[9..11],a = a,b = b,c = c,d = d,e = e,f = f,g = g,h = h);

    RAM512(in = in,load = a,address = address[0..8],out = outa);
    RAM512(in = in,load = b,address = address[0..8],out = outb);
    RAM512(in = in,load = c,address = address[0..8],out = outc);
    RAM512(in = in,load = d,address = address[0..8],out = outd);
    RAM512(in = in,load = e,address = address[0..8],out = oute);
    RAM512(in = in,load = f,address = address[0..8],out = outf);
    RAM512(in = in,load = g,address = address[0..8],out = outg);
    RAM512(in = in,load = h,address = address[0..8],out = outh);

    Mux8Way16(a = outa,b = outb,c = outc,d = outd,e = oute,f = outf,g = outg,h = outh,sel = address[9..11],out = out);
}

RAM16K

16-bit/16384-register memory

CHIP RAM16K {
    IN in[16], load, address[14];
    OUT out[16];

    PARTS:
    // Put your code here:
    DMux4Way(in = load,sel = address[12..13],a = a,b = b,c = c,d = d);

    RAM4K(in = in,load = a,address = address[0..11],out = outa);
    RAM4K(in = in,load = b,address = address[0..11],out = outb);
    RAM4K(in = in,load = c,address = address[0..11],out = outc);
    RAM4K(in = in,load = d,address = address[0..11],out = outd);

    Mux4Way16(a = outa,b = outb,c = outc,d = outd,sel = address[12..13],out = out);
}

RAM anatomy

PC

16-bit program counter.

CHIP PC {
    IN in[16],load,inc,reset;
    OUT out[16];

    PARTS:
    // Put your code here:
    Inc16(in = feedback,out = incout);
    Mux16(a = feedback,b = incout,sel = inc,out = out1);
    Mux16(a = out1,b = in,sel = load,out = out2);
    Mux16(a = out2,b = false,sel = reset,out = out3);

    Register(in = out3,load = true,out = out,out = feedback);
}