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AR# 13213

UniSim, SimPrim, Simulation - How do I simulate the DCM without connecting the CLK Feedback (CLKFB) port? (VHDL)


How can I simulate the DCM without connecting the CLK Feedback (CLKFB) port?


In order to simulate the DCM in VHDL without connecting the CLKFB port, the CLK_FEEDBACK generic must be passed to the simulation model as follows:

component DCM

-- synopsys translate_off

generic (


CLKFX_DIVIDE : integer := 1;

CLKFX_MULTIPLY : integer := 2 ;

CLK_FEEDBACK : string := "NONE"


-- synopsys translate_on

port ( CLKIN : in std_logic;

CLKFB : in std_logic;

DSSEN : in std_logic;

PSINCDEC : in std_logic;

PSEN : in std_logic;

PSCLK : in std_logic;

RST : in std_logic;

CLK0 : out std_logic;

CLK90 : out std_logic;

CLK180 : out std_logic;

CLK270 : out std_logic;

CLK2X : out std_logic;

CLK2X180 : out std_logic;

CLKDV : out std_logic;

CLKFX : out std_logic;

CLKFX180 : out std_logic;

LOCKED : out std_logic;

PSDONE : out std_logic;

STATUS : out std_logic_vector(7 downto 0)


end component;

Without this generic mapping, the simulation model will wait for the CLKFB port to go active, and will thus stay in its initial state.

A parameter does not need to be passed for a similar simulation in Verilog.

AR# 13213
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article