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zlan01
Beginner
285 Views

I instantiaze a pll with 4 output clock,but when I use Derive PLL Clocks command in Timing Analyzer, it only derive two generated clock?

altpll1 altpll1_inst (

   .inclk0 ( chip_clk ),//20Mhz

   .c0 ( sys_clk ), //400Mhz

   .c1 ( uart_clk ), //25Mhz

   .c2 ( clk_50M ), //50Mhz

   .c3 ( clk_30M ),//30Mhz

   .locked ( locked_sig )

   );

according the route " Timing Analyzer->constraints->Create Generated clock "

to open "Create Generated Clock" window ,

11111.png

and the open the ->source window

11112.png

there are just the output clock clk[2] and clk[3] of the pll,where is the clk[0] and clk[1] of the pll?

by the way the ouput clk[0] is 400Mhz, and the ouput clk[1] is 25Mhz ,

and after run the create generate clock command ,there are only

the generate clock clk[2] ,cllk[3], what is the reason ?

 

 

 

 

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3 Replies
Rahul_S_Intel1
Employee
89 Views

Hi ,

When I made a simple PLL and try to put the list fro the name finder , I can see all the out put from the PLL . May I know is that is a problem for you . The same is not view by you

 

Regards,

Rahul S

zlan01
Beginner
89 Views

oh, perhaps because I only do synthesis step, and do not do the fitter step

sstrell
Honored Contributor II
89 Views

And you don't even need to create the generated clocks like this. Just put derive_pll_clocks -create_base_clocks in your .sdc file to automatically create all the clock constraints from the PLL IP.

 

#iwork4intel

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