I am trying to use carry_sum to generate carry chains for quite some time now, mostly without luck (MAX 10). I think I might have fundamentally misunderstood how to use it. If I instanciate several entities of carry_sum and create signals that are the 'cout' output of an entity and the 'cin' of the following one, Quartus just ignores them. Can someone give me a short example on how to use it?
The coutport of the primitive acts as the carry-in for the next element of the carry chain. To use carry_sum primitive, there are few rules you need to consider before using it refer to link below.
1, Verilog HDL example of a CARRY_SUM primitive instantiation.
carry_sum <instance_name> (.sin(<input_wire1>), .cin(<input_wire2>),