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Cadence Innovus: Corner pads placed with no offset

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razer6

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Hi,

I am using the MMMC-flow of Cadence Innovus. Hereby, I set the IO placement file and then initialize the design using the command init_design.
My IO file looks like the following:

Code: 
(globals
    version = 3
    io_order = default
)

(iopad
  (topleft
    (inst name="PADS/CORNER_NW"  offset=1200 )
  )

### left side (W, bottom to top)
  (left
    (inst name="PADS/PAD_gndcore0"   offset= 120 ) 
    (inst name="PADS/PAD_APB_PAddr_DI[3]"   offset= 210 ) 1
    (inst name="PADS/PAD_APB_PAddr_DI[2]"   offset= 300 ) 0
    (inst name="PADS/PAD_APB_PAddr_DI[1]"   offset= 390 ) 
    (inst name="PADS/PAD_APB_PAddr_DI[0]"  offset= 480 ) 
    (inst name="PADS/PAD_APB_PSlverr_SO"  offset= 570 ) 
    (inst name="PADS/PAD_APB_PReady_SO"  offset= 660) 
    (inst name="PADS/PAD_APB_PWrite_SI"  offset= 750 ) # 5
    (inst name="PADS/PAD_APB_PSel_SI"  offset= 840 )  
    (inst name="PADS/PAD_APB_Penable_SI"  offset= 930 ) 
    (inst name="PADS/PAD_Resetn_SI"  offset= 1020 ) 
    (inst name="PADS/PAD_Clk_CI"  offset=1110 ) 
  )
  (bottomleft
    (inst name="PADS/CORNER_SW"     offset=0.00)
  )
### bottom side (S, left to right)
  (bottom
    (inst name="PADS/PAD_APB_PWdata_DI[2]"  offset= 120 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[1]"  offset= 210 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[0]"  offset= 300 ) 
    (inst name="PADS/PAD_APB_PAddr_DI[4]"   offset= 390 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[3]"  offset= 480 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[4]"  offset= 570 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[5]"  offset= 660) 
    (inst name="PADS/PAD_APB_PWdata_DI[6]"  offset= 750 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[7]"  offset= 840 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[8]"  offset= 930 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[9]"  offset= 1020 ) 
    (inst name="PADS/PAD_vddcore0"  offset=1110 ) 
  )
  (bottomright
    (inst name="PADS/CORNER_SE" offset=0.00)
  )
### right side (E, bottom to top)
  (right
    (inst name="PADS/PAD_APB_PWdata_DI[10]"  offset= 120 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[11]"  offset= 210 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[12]"  offset= 300 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[13]"  offset= 390 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[14]"  offset= 480 ) 
    (inst name="PADS/PAD_APB_PWdata_DI[15]"  offset= 570 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[0]"  offset= 660) 
    (inst name="PADS/PAD_APB_PRdata_DO[1]"  offset= 750 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[2]"  offset= 840 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[3]"  offset= 930 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[4]"  offset= 1020 ) 
    (inst name="PADS/PAD_gndio0"   offset= 1110 ) 
  )
### top side (N, left to right)
  (topright
    (inst name="PADS/CORNER_NE"  offset=1200)
  )
  (top
    (inst name="PADS/PAD_APB_PRdata_DO[5]"  offset= 120 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[6]"  offset= 210 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[7]"  offset= 300 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[8]"  offset= 390 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[9]"  offset= 480 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[10]"  offset= 570 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[11]"  offset= 660) 
    (inst name="PADS/PAD_APB_PRdata_DO[12]"  offset= 750 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[13]"  offset= 840 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[14]"  offset= 930 ) 
    (inst name="PADS/PAD_APB_PRdata_DO[15]"  offset= 1020 ) 
    (inst name="PADS/PAD_vddio0"   offset= 1110 ) 
  )
)

This places the IO and corner pads. For the corner pads however, the assigned offset value is not respected and they are placed directly on the edge of the previous IO pad.
You can see that in the following screenshot.

Screenshot from 2018-02-08 20-34-00.png

I can modify the placement of the corner pad in the GUI, but this should work after init_design.

Can someone help me how to get the corner pads being placed with the same pitch as the IO pads and respect the offset value of the IO file?

Thank you!

Best regards,
Robert
 

It doesn't make sense to use offset for the corner. I think you got the margin and the offset options confused.
 

Thanks for your reply. I fixed it by adding an "endspace gap" entry. Is that the right solution?
 

razer6 said:
Thanks for your reply. I fixed it by adding an "endspace gap" entry. Is that the right solution?
Click to expand...

No. You are fixing something that doesn't require a fix. Corner pads are automatically put in the corners. They are not meant to be moved, the other cells move around them.
 

Ok. So, that means there should be any gap between the last functional pad and the corner pad?
This would then also apply for the first pad, which should then be placed with offset=0.

Am I understanding you correctly?

Cheers,
Robert
 

Gaps are never allowed. If you create gaps, intentionally or not, you then put filler IO cells in there to maintain the ring continuity. The first functional IO cells does not need to be placed right next to the corner cell.
 

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