module dflipflop (data ,clk , reset ,q);// Code for Asynchronous Positive Edge triggered D flip flop input data, clk, reset ; output q; reg q; always @ ( posedge clk or negedge reset) if (~reset) begin //what does this block of code mean? q <= 1'b0 // particularly this line end else begin q <= data; // and this one end// endmodule
I am new to learning Verilog, and I have to learn the codes for the various types of flip-flops. However, I haven't been able to understand this one entirely and what it means.
For instance, as the D flip-flop is positive edge triggered, hence we write
posedge clock and it has an asynchronous reset input apart from the normal D input.
But, what I do not understand is the use of the
<= operator in the highlighted lines and what is being done there. Does it mean
q is being assigned a value less than zero? What does data variable refer to in the other line, and what exactly does the line mean as well?