D触发器的VHDL言语计划
D触发器的VHDL言语计划 运用VHDL言语计划D触发器的程序:
LIBRARY ieee; USE ieee.std[_]logic[_]1164.all;
ENTITY dflipflop IS
PORT (D,C : IN STD[_]LOGIC;
Q : OUT STD[_]LOGIC);
END dflipflop;
ARCHITECTURE Behavior OF dflipflop IS
BEGIN
PROCESS( C )
BEGIN
IF C'EVENT AND C='1'
THEN
Q<=D;
END IF;
END PROCESS;
END Behavior;
运用Verilog HDL言语结束D触发器(带R、S端)
//门级
module cfq(s,r,d,clk,q,qbar);
input s,r,d,clk;
output q,qbar;
wire na1,na2,na3,na4;
nand
nand1(na1,s,na4,na2),
nand2(na2,r,na1,clk),
nand3(na3,na2,clk,na4),
nand4(na4,na3,r,d),
nand5(q,s,na2,qbar),
nand6(qbar,q,r,na3);
endmodule
或
//做法级
module dff[_]rs[_]async(clk,r,s,d,q);
input clk,r,s,d;
output q;
reg q;
always@(posedge clk or posedge r or posedge s)
begin
if(r) q<=1'b0;
else if(s) q<=1'b1;
else q<=d;
end
endmodule
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