out16hi.v

来自「Verilog源码」· Verilog 代码 · 共 85 行

module out16hi(scl,sda,outhigh);
input scl,sda;
output[15:0] outhigh;

reg[4:0] mstate;
reg[3:0] pdata,pdatabuf;
reg[15:0] outhigh;
reg StartFlag,EndFlag;

always @(negedge sda)
   if(scl)
      begin
          StartFlag <= 1;
      end
   else if(EndFlag)
          StartFlag <= 0;
always @(posedge sda)
   if(scl)
      begin
         EndFlag <= 1;
         pdatabuf <= pdata;
      end
   else
         EndFlag <= 0;
         
parameter ready = 6'b00_0000,
          sbit0 = 6'b00_0001,
          sbit1 = 6'b00_0010,
          sbit2 = 6'b00_0100,
          sbit3 = 6'b00_1000,
          sbit4 = 6'b01_0000;
          
always @(pdatabuf)
   begin
      case(pdatabuf)
         4'b0001:outhigh = 16'b0000_0000_0000_0001;
         4'b0010:outhigh = 16'b0000_0000_0000_0010;
         4'b0011:outhigh = 16'b0000_0000_0000_0100;
         4'b0100:outhigh = 16'b0000_0000_0000_1000;
         4'b0101:outhigh = 16'b0000_0000_0001_0000;
         4'b0110:outhigh = 16'b0000_0000_0010_0000;
         4'b0111:outhigh = 16'b0000_0000_0100_0000;
         4'b1000:outhigh = 16'b0000_0000_1000_0000;
         4'b1001:outhigh = 16'b0000_0001_0000_0000;
         4'b1010:outhigh = 16'b0000_0010_0000_0000;
         4'b1011:outhigh = 16'b0000_0100_0000_0000;
         4'b1100:outhigh = 16'b0000_1000_0000_0000;
         4'b1101:outhigh = 16'b0001_0000_0000_0000;
         4'b1110:outhigh = 16'b0010_0000_0000_0000;
         4'b1111:outhigh = 16'b0100_0000_0000_0000;
         4'b0000:outhigh = 16'b1000_0000_0000_0000;
      endcase
 end
 
always @(posedge scl)
   if(StartFlag)
      case(mstate)
         sbit0:begin
                  mstate <= sbit1;
                  pdata[3] <= sda;
                  $display("I am in sdabit0");
              end
         sbit1:begin
                  mstate <= sbit2;
                  pdata[2] <= sda;
                  $display("I am in sdabit1");
              end
         sbit2:begin
                  mstate <= sbit3;
                  pdata[1] <= sda;
                  $display("I am in sdabit2");
              end
         sbit3:begin
                  mstate <= sbit4;
                  pdata[0] <= sda;
                  $display("I am in sdabit3");
              end
         sbit4:begin
                  mstate <= sbit0;
                  $display("I am in sdastop");
              end
         default: mstate <= sbit0;
    endcase
endmodule