coutten.abl

VHDL实例,适合大家学习使用

MODULE COUT10
EN,CLK,CLR  PIN;
CY          PIN ;
Q0,Q1,Q2,Q3 PIN ISTYPE 'REG';
COUNT = [Q3..Q0];
EQUATIONS
COUNT.CLK = CLK;
COUNT.AR  = CLK;
WHEN((COUNT ==^H9)&EN) THEN COUNT := 0
    ELSE WHEN(!EN) THEN COUNT := COUNT.FB;
    ELSE WHEN( EN) THEN COUNT := COUNT.FB+1;
CY = (COUNT==^H9)&EN;
TEST_VECTORS([EN,CLR,CLK]->[COUNT,CY])
    @REPEAT 11 {[1,0,.c.]->[.x.,.x.]}
               [0,0,.c.]->[.x.,.x.]
               [.x.,1,.c.]->[.x.,.x.]
END