ID:13045 Converted the fanout from the always-enabled tri-state buffer "<name>" to the node "<name>" into a wire

CAUSE: The specified always-enabled tri-state buffer feeds a non-tri-state logic, an open-drain buffer, or an output pin. The Quartus Prime software converted the fanout from this tri-state buffer to the specified node into a wire. For example, consider the following design that gives the above warning:

	module test1 (input data1, output out); 
	wire tribuf, vcc; 
	assign vcc = 1'b1; 
	assign tribuf = vcc ? data1 : 1'bz; 
	assign out = tribuf; 
	endmodule 

               

Here, the always-enabled tri-state buffer tribuf feeds an output pin, and therefore is converted to a wire. Now consider the following design:

	module test2 (input data1, data2, output out1, inout bidir); 
	wire tribuf, vcc; 
	assign vcc = 1'b1; 
	assign tribuf = vcc ? data1 : 1'bz; 
	and (tmp, data2, tribuf); 
	assign out1 = tmp; 
	assign bidir = tribuf; 
	endmodule 

               

Here, the always-enabled tri-state buffer tribuf feeds an AND gate in addition to feeding a bidirectional pin, so its fanout to the AND gate is converted into a wire. Finally, consider the following design:

	module test3 (input data1, output out); 
	wire tribuf, opndrn, vcc; 
	assign vcc = 1'b1; 
	assign tribuf = vcc ? data1 : 1'bz; 
	assign opndrn = !tribuf ? !vcc : 1'bz; 
	assign out = opndrn; 
	endmodule 

               

Here, the always-enabled tri-state buffer tribuf feeds an open-drain buffer, and hence is converted into a wire.