What is always followed by #(...) pound mean in Verilog?

verilog
weiy picture weiy · Apr 15, 2013 · Viewed 13.3k times · Source

In a simple clock generator example, I see the following code:

always #(cycle/2) clk ~= clk;

I've seen always @(*) before but not pound (#). I tried to find it in the documentation, but all I could find was some reference to "real-valued ports" with no further elaboration.

Answer

Tim picture Tim · Apr 15, 2013

It's a delay operation. It essentially just reads 

always begin
   #(cycle/2) //wait for cycle/2 time
   clk ~= clk;
end

You might sometimes see this used with raw values, like #5 or #10, which means to wait 5 or 10 units of your timescale.

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