create_generated_clock question

[Altera_Forum]

Hi all! 

 I have a 120MHz clock coming into my design. I use this clock on register (called CLK_60) to divide it by 2, to create a 60MHz clock. I believe I have constrained things correctly, but I get a warning that CLK_60 was found without an associated clock assignment.  Here's what I have in my .sdc:  create_clock -name CLK_I_120 -period 8.33333 [get_ports CLK_I_120] create_generated_clock -divide_by 2 -name CLK_60 -source [get_pins CLK_60|clk]   Can anyone tell me where I might be going wrong?   Thanks!

[Altera_Forum]

Hi Awann, 

 You do not tell which clock has to be used as the source for the generated clock. You may try this: create_generated_clock -divide_by 2 -name CLK_60 -source [get_ports CLK_I_120] [get_pins CLK_60|clk]  Grtz,  Richard.

[Altera_Forum]

I realized I did not add the target to my.sdc file. 

 So I changed the line to: create_generated_clock -divide_by 2 -name CLK_60 -source [get_pins CLK_60|clk] CLK_60  That fixed things, and taught me that proper caffeine levels should be achieved before attempting to write constraint files.