See Also

A Register Declaration is used to declare registers, including D, T, JK, and SR flipflops (DFF, DFFE, TFF, TFFE, JKFF, JKFFE, SRFF and SRFFE) and latches (LATCH). The following example shows a Register Declaration:

VARIABLE
   ff : TFF;

The name of this instance of a T flipflop is ff. After making this declaration, you can use the input and output ports of the instance of ff in the format <instance name>.<port name>:

ff.t
ff.clk
ff.clrn
ff.prn
ff.q

Since all primitives have only one output, you can use the name of an instance of a primitive without appending a port name (that is, without .q or .out) on the right of an equation if you want to use its output. Similarly, for all primitives that have a single primary input, that is, all primitives except JKFF, JKFFE, SRFF, and SRFFE, you can use the name of an instance of a primitive without a port name (that is, without .d, .t, or .in) on the left of an equation to connect the primitive to its primary input.

For example, the DFF Function Prototype is FUNCTION DFF(d, clk, clrn, prn) RETURNS (q);. In the following Text Design File (.tdf) excerpt, a = b; is equivalent to a.d = b.q;:

VARIABLE
   a, b : DFF;
BEGIN
   a = b;
END;

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