合肥工业大学：EDA技术与应用（精品课程）：p290_ex9_31_attribute_statement_user_define_cntbuf

-- VHDL code position: p290_ex9_31_attribute_statement_user_define_cntbuf.txt -- Note : This is code for explaing Attribute Specification Statement -- of VHDL -- -- See Also: see 9_29, 9_30, 9_31 -- Debug : no debug --------------------------------------------------------------------------------- -- 9 kinds of Attribute Specification Statement: -- 1) LEFT -- 2) RIGHT -- 3) HIGH -- 4) LOW -- 5) RANGE -- 6) REVERS RANGE -- 7) LENGTH -- 8) EVENT -- 9) STABLE -- Use define Attribute Statement syntax: -- ATTRIBUTE attribute'name : Data type ; or -- ATTRIBUTE attribute'name OF object'name : object'type IS value; -- LIBARY IEEE; USE IEEE.STD_LOGIC_1164.ALL; ENTITY cntbuf IS PORT ( Dir : IN STD_LOGIC; Clk, Clr, OE : IN STD_LOGIC; A, B : INOUT STD_LOGIC_VECTOR ( 0 TO 1 ); Q : INOUT STD_LOGIC_VECTOR ( 3 DOWNTO 0 ) ); ATRRIBUTE PINNUM : STRING; ATRRIBUTE PINNUM OF Clk : SIGNAL IS "1";; ATRRIBUTE PINNUM OF Clr : SIGNAL IS "2";; ATRRIBUTE PINNUM OF Dir : SIGNAL IS "3";; ATRRIBUTE PINNUM OF OE : SIGNAL IS "11";; ATRRIBUTE PINNUM OF Q : "17,16,15,14"; END ENTITY cntbuf;