How does distribuf work ?

Reducing fan-out and transmission loss

When dispatching a signal to more than a few components, we need to take into account the transmission time. In order to optimize the fan-out and transmission loss, we need to divide the signal into a "dispatch tree".

A dispatch tree

It can take a few cycles (log_4(number of components)) for data to reach its target.

entity distribuf is
	generic(
		WDATA :  natural := 20;
		NBOUT :  natural := 20;
		FANOUT : natural := 20
	);
	port(
		clk : in std_logic;
		-- Input
		idata : in std_logic_vector(WDATA-1 downto 0);
		-- Output
		odata : out std_logic_vector(WDATA*NBOUT-1 downto 0)
	);
end distribuf;

• clk : clock signal
• idata : data to dispatch
• odata : data output (idata delayed for a few cycles)