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Signal Attributes
• Attributes Are Named Characteristics of an Object (or Type) Which has a Value That Can Be Referenced.
SIGNAL ATTRIBUTES
• S`Event -- Is TRUE if Signal S Has Changed.
• S`Stable(t) -- Is TRUE if Signal S Has Been Stable For the Last ``t`` Period. If t=0; it is written as S`Stable
• S`Last_value -- Returns the Previous Value of ``S`` Before the Last Change.
Examples : An Edge-Triggered D-FF
D_FF: PROCESS(CLK)
Begin
IF (CLK`Event and CLK = `1`) Then
Q <= D After TDelay;
END IF;
END Process;