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275 | ###############################################################################
# Copyright (c) 2015-2024 by Altair Engineering, Inc.
# All rights reserved.
#
# Altair Engineering, Inc. makes this software available as part of the Vision
# tool platform. As long as you are a licensee of the Vision tool platform
# you may make copies of the software and modify it to be used within the
# Vision tool platform, but you must include all of this notice on any copy.
# Redistribution without written permission to any third party, with or
# without modification, is not permitted.
# Altair Engineering, Inc. does not warrant that this software is error free
# or fit for any purpose. Altair Engineering, Inc. disclaims any liability for
# all claims, expenses, losses, damages and costs any user may incur as a
# result of using, copying or modifying the software.
# =============================================================================
# @script
# I/O Port NMOS and Diode Protection
#
# Algorithm
# 1. Identify the connectivity of I/O ports to internal MOSFETs.
# 2. Check if down diode exists with pos pin connected to ground.
# 3. Check if NFET exists with gate and source connected to ground.
# 4. Verify that the diode is with a minimum perimeter of 300um and
# the NFET with a minimum width of 350um.
# 5. Add the violating nets to the result list.
#
# Example
# demo/api/esd/testcase08.sp
###############################################################################
# -----------------------------------------------------------------------------
# check08DiodeDown - Check diode connected to ground.
# -----------------------------------------------------------------------------
#
proc ESD:check08DiodeDown {db pin extraVar} {
upvar 1 $extraVar extra
##
# get opposite pin
#
set oppositePin [ESD:oppositePin $db $pin]
if {$oppositePin == {}} {
return false
}
##
# get connected net
#
set net [ESD:connectedNet $db $oppositePin]
if {$net == {}} {
return false
}
##
# check ground
#
if {[$db flag $net is ground]} {
lappend extra $oppositePin
return true
}
return false
}
# -----------------------------------------------------------------------------
# check08NmosDown - Check nmos connected to ground.
# -----------------------------------------------------------------------------
#
proc ESD:check08NmosDown {db pin extraVar} {
upvar 1 $extraVar extra
##
# check primitive function
#
set primFunc [$db primFuncOf $pin]
if {$primFunc ne "NMOS"} {
return false
}
##
# get opposite pin
#
set oppositePin [ESD:oppositePin $db $pin]
if {$oppositePin == {}} {
return false
}
##
# get connected net
#
set net [ESD:connectedNet $db $oppositePin]
if {$net == {}} {
return false
}
##
# check ground
#
if {![$db flag $net is ground]} {
return false
}
##
# check gate net
#
set inst [$db oid convertTo inst $pin]
set gatePin [$db getFuncPort $inst -name "gate"]
set gateNet [ESD:connectedNet $db $gatePin]
if {($gateNet == {}) || (![$db oid isequal $gateNet $net])} {
return false
}
lappend extra $gatePin $oppositePin
return true
}
# -----------------------------------------------------------------------------
# check08Port - Check protection .
# -----------------------------------------------------------------------------
#
proc ESD:check08Port {db port resultListVar} {
upvar 1 $resultListVar resultList
##
# get connected net
#
set net [ESD:connectedNet $db $port]
if {$net == {}} {
return
}
##
# loop over all connected pins
#
set gatePins {}
set nmosDownPins {}
set diodeDownPins {}
set extraPins {}
$db flat foreach pin -addHier $net pin {
##
# Ignore start port
#
if {[$db oid isequal $pin $port]} {
continue
}
##
# store hierPins
#
if {[$db oid type $pin] == "port"} {
lappend extraPins $pin
continue
}
##
# Get pin function of inst
#
set pinFunc [ESD:funcName $db $pin]
##
# Check all allowed types
#
switch -- $pinFunc {
"drain" -
"source" {
if {[ESD:check08NmosDown $db $pin extraPins]} {
lappend nmosDownPins $pin
}
}
"cathode" {
if {[ESD:check08DiodeDown $db $pin extraPins]} {
lappend diodeDownPins $pin
}
}
"gate" {
lappend gatePins $pin
}
default {
##
# all other pins (and hierpins) which might be connected
#
lappend extraPins $pin
}
}
}
##
# Check for gate connection
#
if {[llength $gatePins] > 0} {
##
# set oids, if the oid list is too large, show only path from
# first gate to port.
#
set oids [concat $gatePins $nmosDownPins $diodeDownPins $extraPins]
if {[llength $oids] > 10} {
set firstGate [lindex $gatePins 0]
set oids [ESD:filterOids $db $firstGate $port $oids]
}
##
# Missing down nmos.
#
if {([llength $nmosDownPins] == 0) && ([llength $diodeDownPins] ==0)} {
ESD:appendResult resultList $port $oids "no down diode and nmos"
return
}
##
# Missing down nmos.
#
if {[llength $nmosDownPins] == 0} {
ESD:appendResult resultList $port $oids "no down nmos"
return
}
##
# Missing down diode
#
if {[llength $diodeDownPins] == 0} {
ESD:appendResult resultList $port $oids "no down diodes"
return
}
##
# OK
#
ESD:appendResult resultList $port $oids ""
}
}
# =============================================================================
# Check08 - I/O Port NMOS and Diode Protection.
# =============================================================================
#
proc ESD:Check08 {db} {
##
# Initialize the result list.
#
set resultList {}
##
# Get top module.
#
set top [$db get_top_design]
##
# Count top level ports
#
set count 0
$db foreach port $top port {
incr count
}
##
# Loop over all top level ports
#
$db foreach port $top port {
zprogress push "" [expr {double([incr i]) / $count}]
ESD:check08Port $db $port resultList
if {[zprogress pop]} {
break
}
}
##
# Return the calculated result.
#
return $resultList
}
|