|
|
For any parameterized function, you must declare all parameters used in the function, their types, and their values. The following example shows a VHDL design file that instantiates the lpm_ram_dq function. Attribute Declarations are used to declare the syn_black_box attribute and the name and type of each parameter. The syn_black_box attribute has the boolean type; refer to Quartus® II Help for information on whether a parameter is of integer or string type. Attribute Specifications are then used assign values to each parameter.
The following example shows a direct instantiation of an LPM function. To use the MegaWizard® Plug-In Manager (Tools menu) to create the function, and then instantiate it in a design, refer to Create a Design for Use with the Synplify Software.
PRE> entity myram is port (clock, we: in bit; data : in bit_vector (3 downto 0); address: in bit_vector (1 downto 0); q: out bit_vector (3 downto 0)); end myram; architecture arch1 of myram is -- Declare the component component myram_4x4 port (data: in bit_vector (3 downto 0); address: in bit_vector (1 downto 0); inclock, outclock, we: in bit; q: out bit_vector (3 downto 0) ); end component; -- Declare the syn_black_box and parameters and their types attribute syn_black_box: boolean; attribute LPM_WIDTH: integer; attribute LPM_WIDTHAD: integer; attribute LPM_TYPE: string; -- Assign values to each attribute attribute syn_black_box of myram_4x4: component is true; attribute LPM_WIDTH of myram_4x4: component is 4; attribute LPM_WIDTHAD of myram_4x4: component is 2; -- Specify the name of the LPM function as the value of the -- LPM_TYPE attribute attribute LPM_TYPE of myram_4x4: component is "LPM_RAM_DQ"; begin -- Instantiate the LPM component u1: myram_4x4 port map(data, address, clock, clock, we, q); end arch1;|
- PLDWorld - |
|
|
| Created by chm2web html help conversion utility. |