ID:14813 Tri-state node(s) do not directly drive top-level pin(s)
CAUSE: The design contains tri-state nodes that drive non-tri-state logic, but the chip does not support internal tri-states. As a result, the Quartus Prime software converts all the tri-state nodes feeding internal logic to an equivalent logic. For example, in the following design, the fan-out from the node
tribuf
to the AND
gate is converted to an OR
gate.
module test1 (input oe1, data1, in, output out, inout bidir);
wire tribuf, tmp;
assign tribuf = oe1 ? data1 : 1'bz;
and(tmp, in, tribuf);
assign bidir = tribuf;
assign out = tmp;
endmodule
In the following design, the node triwire
is converted to a selector.
module test2 (input oe1, data1, oe2, data2, in, output out);
wire triwire, tmp;
assign triwire = oe1 ? data1 : 1'bz;
assign triwire = oe2 ? data2 : 1'bz;
and(tmp, in, triwire);
assign out = tmp;
endmodule
See the sub-messages below to view a list of the affected tri-state nodes and a more detailed Help. ACTION: Avoid this warning by either removing the non-tri-state fan-outs of the affected tri-state nodes or replacing the tri-state nodes with non-tri-state logic.