Pins of a Flip -flop | reset and preset | verilog code

Discussion in 'Homework Help' started by Hareesh143, Nov 15, 2014.

  1. Hareesh143

    Thread Starter New Member

    Nov 15, 2014
    Hi Guys,

    I know this seems to be a basic question, but also it doesnt seem to be very basic.
    Please help out with this,

    We all know , the pins for a D flip-flop are D,clk, Preset and reset (inputs) and the Q and Q` are outputs.
    Here comes the question, in the real chip does the flop really have both the preset and reset pins ?
    Because I see only either preset or reset are needed but not both,

    For example, in this below example "a <=0" indicates it needs only a reset. if the code had been "a<=1" then it would have needed preset.
    As in verilog synthesizable code we write

    always @ (posedge clk or negedge reset_n) begin
    if (!reset_n) begin
    a <=0;

    Can some one please clarify this!!.

    Or is it, we will have either a preset or reset based on the code written , ???