I am trying to write SDC contraints for given design...
Input clocks are defined by "create_clock" commands (not shown in the picture).
MUXes are covered by "set_clock_groups" commands.
Freq_div outputs should be covered by "create_generated_clock" commands.
I am not 100% sure about the pin definitions, could you guys please check it?
Thanks for the reply. The tool is fine with the definitions
I am more concerned about the timing results based on SDC / correct constraining of muxed input and output.
See, I am not familiar with muxed clock designs at all and the picture/SDC commands are just what I've gathered online, but there are conflicting (and confusing) answers so I wanted more experienced designer to look at it and maybe clear things up.
why not just defining:
1. a clock network from mux_in.Z and stop to mux.out input pins to equilibrate the flop inside the divider.
2. a clock network from mux_out.Z, to equilibrate the remaining design.
OR
transform the FREQ_DIV to generate a clock enable signal with will acts on the clock gating cell, so no need of the mux_out.