Using TNM_NET to create Groups
NET clock TNM_NET=clk_group;
TNM_NET is equivalent to TNM on a net except for pad nets.
When placing a TNM on a pad net the TNM would locate itself on the pad and not trace forward through the buffer to the next synchronous element. TNM_NET was created for this purpose. If you place a TNM_NET on a pad net, it will trace through the buffer to the next synchronous element.
TNM_NET is extremely useful for synthesis designs. The only meaningful net names are the ones directly connected to pads.
TNM_NET can be used in UCF or NCF only.