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The UDP instantiation provides a means of using UDP in modules.
udp_name (strengths) #(delays) instance_name[range] (list of ports);
UDPs can be instantiated only within modules.
The name of an instance is optional (Example 1). A UDP instantiation can contain strength and delays declarations (Example 2). UDPs do not support high-impedance (z) values, therefore only two delays are permitted. Signals connected to input ports can be any net or reg data type. Only net data type variables can be connected to the output port. The strength declaration can contain only drive strength.
It is possible to specify an array of UDP instances by using a range (Example 3).
Example 1
primitive d_ff (q, clk, d);
...
endprimitive
d_ff (q, clk, d);
The name of an instance is optional.
Example 2
d_ff (weak1, strong0) #5 d1 (q, clk, d);
UDP instance with strength and delay declaration.
Example 3
wire [3:0] q;
reg [3:0] d;
reg clk;
d_ff flips[3:0] (q, clk, d);
UDP instantiation can contain up to two delay values.
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