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2 Replies Last post: Jun 29, 2009 12:38 AM by karthikm  
suresh.pachha Lurker 1 posts since
Feb 26, 2009
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Jun 25, 2009 11:58 PM

Source Names That Appear On More Than One Object

i am getting following error in LVS report

 

  5    ** missing net **                                        VDD

--------------------------------------------------------------------------------------------------------------

  6    ** missing net **                                        VSS


**************************************************************************************************************
                                  INCORRECT PORTS

DISC#  LAYOUT NAME                                              SOURCE NAME
**************************************************************************************************************

  7    ** missing port **                                        VDD on net: VDD
  8    ** missing port **                                        VSS on net: VSS

 

and it is showing in detailed report LVS REPORT OPTION

 

  --- Devices on source net VSS ---

      (cell ports)                                              (cell ports)
        VDD_PLL: VDD_PLL                                          VDD_PLL: VDD_PLL
        VDDA_PLL: VDDA_PLL                                        VDDA_PLL: VDDA_PLL
        VDD: VDD                                                  VDD: VDD
        VDD_MDDI: VDD_MDDI                                        VDD_MDDI: VDD_MDDI
        VDDA_MDDI: VDDA_MDDI                                      VDDA_MDDI: VDDA_MDDI
        VCCQ: VCCQ                                                VCCQ: VCCQ
        vddz: VDDZ                                                vddz: VDDZ
        vddana: VDDANA                                            vddana: VDDANA
        VSS: VSS                                                  VSS: VSS
        VSSA_MDDI: VSSA_MDDI                                      VSSA_MDDI: VSSA_MDDI
        VSS_PLL: VSS_PLL                                          VSS_PLL: VSS_PLL
        VSSA_PLL: VSSA_PLL                                        VSSA_PLL: VSSA_PLL
        VSS_MDDI: VSS_MDDI                                        VSS_MDDI: VSS_MDDI
        vccio_2_: vccio_2_                                        vccio_2_: VCCIO_2_
        gpio_57: gpio_57                                          gpio_57: gpio_57
        vpp6: vpp6                                                vpp6: vpp6
        mddi_d0_n: mddi_d0_n                                      mddi_d0_n: mddi_d0_n
        .

        .

        .

        .

        adq0_2_8m_ad7_2_16m: adq0_2_8m_ad7_2_16m                  adq0_2_8m_ad7_2_16m: adq0_2_8m_ad7_2_16m
        adq1_2_8m_ad6_2_16m: adq1_2_8m_ad6_2_16m                  adq1_2_8m_ad6_2_16m: adq1_2_8m_ad6_2_16m
        adq1_1_8m_ad6_1_16m: adq1_1_8m_ad6_1_16m                  adq1_1_8m_ad6_1_16m: adq1_1_8m_ad6_1_16m
        ** missing net **                                                      VDD: VDD
        ** missing net **                                                      VSS: VSS

 

 

also showimg

 

Source Names That Appear On More Than One Object:

   Ports:        VDD VSS
   Nets:         VDD VSS

 

can any one please explain why the tool showing 2 VDD & 2 VSS in source net list

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chris_balcom jedi 162 posts since
Apr 3, 2008
Currently Being Moderated
Jun 26, 2009 8:28 AM in response to: suresh.pachha
Re: Source Names That Appear On More Than One Object

Hi Suresh,

 

Is it possible that there were two different ground names in the source, and that *.EQUIV was used to bring them together as VSS ? That doesn't work the same way as *.CONNECT  or *.JOIN which actually join together nets of different names.

 

Here are links to a few TechNotes that describe this problem and solution in more detail:

 

http://supportnet.mentor.com/reference/technotes/public/technote.cfm?tn=MG76485

 

http://supportnet.mentor.com/reference/technotes/public/technote.cfm?tn=MG44056

karthikm Lurker 1 posts since
Jun 22, 2009
Currently Being Moderated
Jun 29, 2009 12:38 AM in response to: chris_balcom
Re: Source Names That Appear On More Than One Object

Hi Suresh,

 

    I think, It should be probably because of pwr/gnd net openings. Check whether you have defined toplevel port name for your pwr/gnd pins

in the layout. If not, use the 'LAYOUT TEXT' option to define the top-level pg pins. It will help to isolate the pwr/gnd nets open. And make sure

your lvs extraction report is clean for this case.

 

- Karthik

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