antenna diodes

Can you explain what do you mean by "input toplevel pins". Any net in a design should connect to a instance pin. The instance can be a pad, std cell, mem macro or a analog macro.

li siang

I am talking about the top level I/O pins. Input /output to the platform from SOC.
When I try to add antenna diodes to the top_level I/O pins the tool does not add it. What can be the reason?.
Hope I have answered your doubt.

Usha

Hi usha,

Until the attachDiode command is enhanced to allow IO pins in addition to instance pins, you'll need to use a script to attach the diode cells to the input IO pins.

There's an example script shipped with the software that attaches diodes to all of the IO pins. It's called "userAddDiodesToIOs.tcl" and it is in the $ENCOUNTER/tools/fe/gift/scripts/tcl directory. Note that this script attaches the specified diode cell to *all* IO pins (input and output). You'd need to modify the script to only work on input pins to get your desired functionality.

Here's a similar script that only operates on inputs:

proc userAttachIoDiodesToInputs {diodeCellName} {
Puts "Attaching diode cells to each block-level inputs ports..."
set count 0
set diodeCell [dbGetCellByName $diodeCellName]
if {$diodeCell == "0x0"} {
Puts "Couldn't find a diode cell in the library called \"$diodeCellName\""
Puts "Quitting..."
return
}
dbForEachCellFTerm [dbGetCellByName $diodeCellName] fterm {
set diodeCellFTermName [dbFTermName $fterm]
}
dbForEachCellFTerm [dbHeadTopCell] fterm {
if {[dbIsFTermInput $fterm]} {
set net [dbFTermNet $fterm]
if {$net > 0} {
set netName [dbNetName $net]
set ftermName [dbFTermName $fterm]
set instName "${ftermName}_user_added_diode"
addInst -cell $diodeCellName -inst $instName
set ftermLoc [dbFTermLoc $fterm]
set x [dbDBUToMicrons [dbLocX $ftermLoc]]
set y [dbDBUToMicrons [dbLocY $ftermLoc]]
placeInstance $instName $x $y -placed
attachTerm $instName $diodeCellFTermName $netName
incr count
}
}
}
refinePlace
setBlockPlacementStatus -name *user_added_diode -status preplaced
Puts "Done. Added $count diode cell(s)."
}

This script is intended to be run on a design that has the floorplan loaded prior to running placement.

Hope this helps,
Bob