Introduction

Verilog is a HARDWARE DESCRIPTION LANGUAGE (HDL). A hardware description language is a language used to describe a digital system: for example, a network switch, a microprocessor or a memory or a simple flip-flop. This just means that, by using a HDL, one can describe any (digital) hardware at any level.


D FLIP-FLOP CODE


// D flip-flop Code
module d_ff ( d, clk, q, q_bar);
input d ,clk;
output q, q_bar;
wire d ,clk;
reg q, q_bar;
always @ (posedge clk)
begin
q <= d;
q_bar <= ! d;
end
endmodule




One can describe a simple Flip flop as that in the above figure, as well as a complicated design having 1 million gates. Verilog is one of the HDL languages available in the industry for hardware designing. It allows us to design a Digital design at Behavior Level, Register Transfer Level (RTL), Gate level and at switch level. Verilog allows hardware designers to express their designs with behavioral constructs, deferring the details of implementation to a later stage in the final design.