【DC系列教程2--Timing and Area Constrains】

Goal:

• determin the unit of time in the target library; //设置时间精度
• Create a Design Compiler timing and area constrains file based on a provided schematic and specifacation //自己写时序和面积约束文件根据给定原理图
• Verify the syntax of the constrains prior to applying them to a design.
• Apply the constraints to a design. //约束应用于设计
• Validate the completeness and correctness of the applied constrains.

Lab Flow:

依赖输入

RTL（Design Schematic）
Design Specification
Design Schematic：设计框图，可以tool bar里面点击生成；
形如下图，其实类似在Design Spec里面自己画的模块框图是的，这个更细点带着布尔门和寄存器；

Design Specification

详细设计规格具体要求：
Clock Definition
Register Setup Time
Input Ports(sequential logic)
Combinational Logic
Design Area

Lab Demo

1.Setup for the .synopsys_dc.setup
read_db sc_max.db // read_db
list_libs //check for libs
report_lib cb13fs120_tsmc_max // if want to redirect,use below

redirect -file lib.rpt {report_lib cb13fs120_tsmc_max}
exit // for exit dc_shell
gvim lib.rpt
grep -i “unit” lib.rpt

2.Create a Timing and Area Constrains File
If do not know how to do ,ref the .solutions.

• create xxx.con under ./scripts/

touch lab4.con

• Based on the Design Spec and Design Schematic，as well as the appropriate time unit，Get the required constrains writed in lab4.con

#Dont know how to write
cp .solutions/lab4.con ./scripts
de_shell: source scripts/lab4.con

• check for verify the constrains applied to design

check_timing
report_clock
report_clock -skew
report_port -verbose

• write out the applied constrains to a file for further checking

write_script -out scripts/lab4.wscr

• tkdiff cmd to compare the .solutions/lab4.wscr with scripts/lab4.wscr
  save the design as unmapped/MY_DESIGN.ddc and exit.

GuI: saved as..
unix: write -hierarchy -format ddc -output /xx/xxx/xx/xx/xx/xx.ddc

【Ref】
[1] https://blog.csdn.net/weixin_44726874/article/details/131088674
[2] https://max.book118.com/html/2016/1113/62845423.shtm