属性描述与定义语句
8页1、属性描述与定属性描述与定属性描述与定属性描述与定义语句义语句义语句义语句EDA EDA 技术实用教程技术实用教程 属性描述与定义语句属性描述与定义语句 1.1.信号类属性信号类属性 (NOT clockSTABLE AND clock=1)(clockEVENT AND clock=1)2.2.数据区间类属性数据区间类属性 .SIGNAL range1:IN STD LOGIC VECTOR(0 TO 7);.FOR i IN range1RANGE LOOP .属性描述与定义语句属性描述与定义语句 3.3.数值类属性数值类属性 .PROCESS(clock,a,b);TYPE obj IS ARRAY(0 TO 15)OF BIT;SIGNAL ele1,ele2,ele3,ele4 :INTEGER;BEGIN ele1=objRIGNT;ele2=objLEFT;ele3=objHIGH;ele4=objLOW ;.【例【例10-32】LIBRARY IEEE;-PARITY GENERATORUSE IEEE.STD_LOGIC_1164.ALL;ENTITY parity I
2、S GENERIC(bus_size:INTEGER:=8);PORT(input_bus:IN STD_LOGIC_VECTOR(bus_size-1 DOWNTO 0);even_numbits,odd_numbits:OUT STD_LOGIC);END parity;ARCHITECTURE behave OF parity ISBEGINPROCESS(input_bus)VARIABLE temp:STD_LOGIC;BEGIN temp:=0;FOR i IN input_busLOW TO input_busHIGH LOOPtemp:=temp XOR input_bus(i);END LOOP;odd_numbits=temp;even_numbits=NOT temp;END PROCESS;END behave;属性描述与定义语句属性描述与定义语句 4.4.数组属性数组属性LENGTH LENGTH.TYPE arry1 ARRAY(0 TO 7)OF BIT;VARIABLE wth:INTEGER;.wth1:=arry1LENGTH;-wth1=8.属性描
3、述与定义语句属性描述与定义语句 5.5.用户定义属性用户定义属性 ATTRIBUTE 属性名属性名:数据类型数据类型;ATTRIBUTE 属性名属性名 OF 对象名对象名:对象类型对象类型IS 值值;LIBRARY synplify;USE synplicity.attributes.all;LIBRARY 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);ATTRIBUTE PINNUM:STRING;ATTRIBUTE PINNUM OF Clk:signal is 1;ATTRIBUTE PINNUM OF Clr:signal is 2;ATTRIBUTE PINNUM OF Dir:signal is 3;ATTRIBUTE PINNUM OF OE:signal is 11;ATTRIBUTE PINNUM OF Q:signal is 17,16,15,14;END cntbuf;5.5.用户定义属性用户定义属性 谢谢观看!谢谢观看!谢谢观看!谢谢观看!EDA EDA 技术实用教程技术实用教程
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