UDP Instantiation
Formal Definition
The UDP instantiation provides a means of using UDP in modules.
Simplified Syntax
udp_name (strengths) #(delays) instance_name[range] (list of ports);
Description
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).
Examples
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);
Important Notes
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