我们之前分享过在hierarchical flow后端实现中为了确保顶层flatten时timing signoff和physical signoff看到的情况和模块级看到的情况一致,我们会在模块io port添加io port buffer(主要是timing,antenna一致性)。实际上在芯片级我们还会给各大子模块Block和IP的接口添加buffer。
数字IC后端设计实现 | PR工具中到底应该如何控制density和congestion?(ICC2&Innovus)
在一些数模混合设计中,为了考虑CDM问题,我们会在模块接口处添加Antenna 二极管,具体如下图所示。
为了防止CDM,我们需要对这个HDMI IP的所有端口添加antenna diode。如果IP内部已经添加过了则可以跳过。
数字IC后端设计如何从零基础快速入门?(内附数字IC后端学习视频)
在我们低功耗四核A7 Top项目中,我们也可以对各个cpu子模块接口添加io pin buffer。这样即便子模块a7core的lib文件不准确,在a7top顶层也不会看到跟子模块接口的长线了。
今天分享下每个项目都会用到的给各种Block添加buffer和antenna的万能脚本。这个又是一个练习脚本的好例子。
proc add_buffer_diode_on_block_pins {args} {
parse_proc_arguments -args a r g s o p t i o n s s e t b u f f e r c e l l " args options set buffer_cell " argsoptionssetbuffercell"options(-buffer)"
set diode_cell “ o p t i o n s ( − d i o d e ) " s e t b u f f i l e " options(-diode)" set buf_file " options(−diode)"setbuffile"options(-buffer_eco_file)”
set diode_file “ o p t i o n s ( − d i o d e e c o f i l e ) " s e t p r e f i x " options(-diode_eco_file)" set prefix " options(−diodeecofile)"setprefix"options(-prefix)”
set j 0
set file1 [open $buf_file w]
set file [open $diode_file w]
puts $file1 “setEcoMode -updateTiming false -refinePlace false”
puts $file1 "setEcoMode -batchMode true "
foreach pin [dbGet selected.instTerms] {
puts $file1 “ecoAddRepeater -cell $buffer_cell -term [dbGet $pin.name] -name KaTeX parse error: Expected group after '_' at position 13: {prefix}_BUF_̲j -loc [dbGet $pin.pt]”
puts $file “addInst -cell $diode_cell -inst KaTeX parse error: Expected group after '_' at position 15: {prefix}_DIODE_̲j -loc [lindex [dbGet $pin.pt] 0]”
set net [dbGet $pin.net.name]
puts $file “attachTerm KaTeX parse error: Expected group after '_' at position 15: {prefix}_DIODE_̲j MINUS $net”
incr j
}
puts $file1 “setEcoMode -batchMode false "
puts f i l e 1 " r e f i n e P l a c e − i n s t ∗ file1 "refinePlace -inst * file1"refinePlace−inst∗{prefix}"
puts $file1 "dbSet [dbGet top.insts.name BLOCK_ISO -p].pStatus fixed"
puts f i l e " r e f i n e P l a c e − i n s t ∗ file "refinePlace -inst * file"refinePlace−inst∗{prefix}"
puts $file "dbSet [dbGet top.insts.name ${prefix}_ -p].pStatus fixed”
close $file
close $file1
puts “Created eco files $buf_file and $diode_file”
puts “you need to source these files to implement the ECO”
}
define_proc_arguments add_buffer_diode_on_block_pins
-info “Generate ECO files to add buffers and antenna diodes on the I/Os of the selected block\n”
-define_args {
{-buffer “Buffer libcell to be inserted” “none” string {required}}
{-diode “Diode libcell to be inserted” “none” string {required}}
{-buffer_eco_file “ECO file name for buffer insertion” “none” string {required}}
{-diode_eco_file “ECO file name for diode insertion” “none” string {required}}
{-prefix “Prefix to use for the inserted instances names” “none” string {required}}
}
return
###使用方法
add_buffer_diode_on_block_pins -buffer BUFFD3BWP40P140LVT -diode ANTENNABWP40P140LVT -buffer_eco_file buffer_eco.tcl -diode_eco_file diode_eco.tcl -prefix IP_ISOLATION
###读入上述脚本生成的添加buffer和添加antenna diode脚本
##source eco_buf.tcl
##source eco_diode.tcl
下图所示为添加好子模块cpu buffer的效果图。
【思考题】为何这个脚本在执行过程中会报如下所示的ERROR(IMPOPT-616)?