数电单人实验第六次

本次为大家带来三个实验，十分有重要意义的实验。

第一部分：实验代码

div2的文件讲述的是移位除法器

module div2(clk, reset, start, A, B, D, R, ok, err);
   parameter n = 32;
   parameter m = 16;
   
   input clk, reset, start;
   input [n-1:0] A, B;
   output [n+m-1:0] D;
   output [n-1:0] R;
   output ok, err;
   
   wire invalid, carry, load, run;
   
   div_ctl UCTL(clk, reset, start, invalid, carry, load, run, err, ok);
   div_datapath  UDATAPATH(clk, reset, A, B, load, run, invalid, carry, D, R);
   
endmodule

module div_ctl(clk, reset, start, invalid, carry, load, run, err, ok);
   parameter n = 32;
   parameter m = 16;
   parameter STATE_INIT = 3'b001;
   parameter STATE_RUN = 3'b010;
   parameter STATE_FINISH = 3'b100;
   input clk, reset, start, invalid, carry;
   output load, run, err, ok;
   
   reg [2:0] current_state, next_state;
   reg [5:0] cnt;
   reg load, run, err, ok;
    
   always @(posedge clk or negedge reset)
   begin
      if(!reset) begin
         current_state <= STATE_INIT;
         cnt <= 0;
      end else begin
         current_state <= next_state;
         if(run) cnt <= cnt + 1'b1;        
      end
   end
   
   always @(posedge clk or negedge reset)
   begin
      if(!reset) begin
         err <= 0;
      end else if(next_state==STATE_RUN) begin
         if(invalid) err <= 1;        
      end
   end
   
	always @(current_state or start or invalid or carry or cnt)
   begin
      load <= 1'b0;
      ok <= 1'b0;
      run <= 1'b0;
       
      case(current_state)
         STATE_INIT: begin
            if(start) next_state <= STATE_RUN;
            else next_state <= STATE_INIT;
            load <= 1;
         end
         STATE_RUN : begin
            run <= 1;
            if(invalid) begin
               next_state <= STATE_FINISH;   
            end else if(cnt==(n+m-1)) begin
               next_state <= STATE_FINISH;    
            end else begin
               next_state <= STATE_RUN;
            end
         end
         STATE_FINISH : begin
            ok <= 1;
            next_state <= STATE_FINISH;    
         end
         default : begin
            next_state <= STATE_INIT;    
         end
      endcase
   end   
endmodule


module div_datapath(clk, reset, A, B, load, run, invalid, carry, D, R);
   parameter n = 32;
   parameter m = 16;
   input clk, reset;
   input [n-1:0] A, B;
   input load, run;
   output invalid, carry;    
   output [n+m-1:0] D;
   output [n-1:0] R;

   reg [n+n+m-2:0] R0;
   reg [n+m-1:0] D;
   reg [n-1:0] B0;
   reg carry;
   
   wire invalid;
   wire [n-1:0] DIFF, R;
   wire CO;

   assign R = {carry, R0[n+n+m-2:n+m]};   
   assign invalid = (B0==0);
   
   sub  sub(R0[n+n+m-2:n+m-1], B0, 1'b0, DIFF, CO);  //ʵÀý»¯¼õ·¨Æ÷
   
   always @(posedge clk)
   begin
      if(load) begin                              //³õʼ½×¶Î
         D <= 0;
         R0 <= {{(n-1){1'b0}}, A, {m{1'b0}}};
         B0 <= B;
         carry <= 1'b0;    
      end 
else if(run) begin                         //½áÊø½×¶Î
         if(CO && !carry) begin 
           R0 <= { R0, 1'b0 };
           D <= { D[n+m-2:0], 1'b0 };
           carry <= R0[n+n+m-2];
         end else begin                          //µü´ú½×¶Î
           R0 <= { DIFF, R0[n+m-2:0], 1'b0 };
           D <= { D[n+m-2:0], 1'b1 };
           carry <= DIFF[n-1];
         end
      end
   end
endmodule


module sub(A, B, CI, DIFF, CO);
   parameter n = 32;
   input [n-1:0] A, B;
   input CI;
   output [n-1:0] DIFF;
   output CO;
   
   assign {CO, DIFF} = {1'b0, A} - {1'b0, B} - {{n{1'b0}}, CI};
endmodule

7-1的代码的讲解：SR锁存器延迟模型

module my_rs(reset,set,q,qbar);
input reset,set;
output q,qbar;

nor #(1) n1(q,reset,qbar);
nor #(1) n2(qbar,set,q);

endmodule
 
module tb_71;
reg set,reset;
wire q,qbar;

initial
begin
    set<=0;reset<=1;
#10 set<=0;reset<=0;
#10 set<=1;reset<=0;
#10 set<=1;reset<=1;
end

my_rs rs1(reset,set,q,qbar);

initial
$monitor($time,"set= %b,reset= %b,q= %b,qbar= %b",set,reset,q,qbar);

endmodule

8-1的代码讲解：独热码状态器的模型

module ex8_1(clock,reset,x,y1,y2);
input clock,reset;
input x;
output y1,y2;
reg y1,y2;

reg[3:0] cstate,nstate;

parameter s0=4'b0001,s1=4'b0010,     
          s2=4'b0100,s3=4'b1000;
          
always @(posedge clock or posedge reset)    
begin
  if(reset)
    cstate<=s0;
  else
    cstate<=nstate;
end

always @(cstate or x)           
begin
  case(cstate)
  s0:begin
       if(x==0)
         nstate=s1;
       else
         nstate=s3;
     end
  s1:begin
       if(x==0)
         nstate=s2;
       else
         nstate=s0;
     end
  s2:begin
       if(x==0)
         nstate=s3;
       else
         nstate=s1;
     end
  s3:begin
       if(x==0)
         nstate=s0;
       else
         nstate=s2;
     end
  default:nstate=s0;
  endcase
end

always @(cstate or x)      
begin
  case(cstate)
  s0:begin
       if(x==0)
         y1=1;
       else
         y1=0;
     end
  s1:begin
       if(x==0)
         y1=0;
       else
         y1=0;
     end
  s2:begin
       if(x==0)
         y1=0;
       else
         y1=0;
     end
  s3:begin
       if(x==0)
         y1=0;
       else
         y1=1;
     end
  default:y1=0;
  endcase
end

always @(cstate or x)              
begin
  if(cstate==s0 && x==0)          
    y2=1;
  else if(cstate==s3 && x==1)      
    y2=1;
  else
    y2=0;
end

endmodule


module tb_ex81;
reg x,clock,reset;
wire y1,y2;

initial clock=0;
always #5 clock=~clock;

initial
begin
  reset=0;
  #15 reset=1;
  #15 reset=0;
  #10000 $stop;
end

initial
begin 
  #10  x=1;
  #500 x=0;
end

ex8_1 myex81(clock,reset,x,y1,y2);

endmodule

第二部分：实验的波形图

div2的实验波形图
7-1的波形图

8-1的波形图

当我们把实验的波形图再次细分时，我们会看到：
div2的波形图

7-1的波形图

8-1的波形图

实验第三部分：实验的总结

我们结合书本上的内容完成实验的时，我们要注意代码的正确与否。代码饿错误会带来数据上的变动，让波形图发生变化。同时我们自己在做完实验时，应该“回头看”，把自己打写代码的问题再重新捡起来思考，有没有更好的方法能够改变我们自己的不好习惯。

标签：reset,单人,clk,数电,波形图,input,carry,第六次,parameter
来源： https://blog.csdn.net/wwrNB/article/details/117815259