Automated_Circuit_To_MAGIC_VLSI

 

Automated_Circuit_To_MAGIC_VLSI

Project Name: Automated Circuit To MAGIC VLSI layout Using Open Source EDA Tools.

VLSI design flow includes system specification, architectural design, functional & logic design, circuit design, physical design, fabrication, packaging & testing, chip. In physical esign process like  routing, placement, etc are involved. This project aims to convert a circuit into its MAGIC Layout format. MAGIC software is a open source EDA tool which is used for making layout of circuit.

Basically if we are representing a circuit into code format then using some coding algorithm we can implement its magic VLSI layout. So, here circuit netlist,design rules, librecell layout are used to generate output.

Basic algorithm is :

Input files [Spice Netlist + Design Rules] -----> Librecell Layout as conversion tool -----> Output i.e layout [GDS,LEF,MAG]

We can generate spice netlist of any circuit using circuit design tools,open source EDA tools. Design rules are the rules which are associated with ƛ rule used in stick diagram, layout. Stick diagram represents layer information through color code. Layout consists of contacts, metal, polysilicon, etc. This layers are represented using color code in a stick diagram.

Let's Start

Steps Involved :

  • Installing Python3, Ngspice, Z3 Solver
  • Creating a python virtual environment
  • Installing librecell using git
  • Applying Conversion Commands
  • Installing MAGIC To see Layout
  • Installing klayout to see Layout.

Downloading Python3, Ngspice, Z3 Solver

Requirement Of Python3 : In layout process, designing rules are described by the tech file in the form of python file. Requirement Of z3 solver: The routing process is involved in layout which is carried out by z3 solver. Here Dijkstra's algorithm is used for routing. Requirement of ngspice : Here we are using spice netlist as input, this spice netlist is checked by ngspice. Requirement of magic: MAGIC software is used to view, and edit layout. It is a VLSI layout tool. Requirement Of klayout : Klayout is used to see graphic data database system i.e GDS file. {Opencad : We can use open cad software to view 3D design of the layout. Openscad uses gds3xtrude to convert the layout from 2D to 3D. In this project, it is used for visualization purposes.}

Input & Output Files

So using librecell we get to know that we can convert spice netlist to its layout.

Input files used :

  • Spice netlist [.sp]
  • Tech file [.py]
  • cell name

Output Files obtained :

  • Graphic Database System File .gds]
  • Library Exchange Format [.lef]

To install python3 use the following command :

sudo apt-get install python3 `

To install ngspice use the following command :

sudo apt-get install ngspice `

To install z3 solver use the following command :

sudo apt-get install z3 `

We will also require MAGIC software to check/read Layout(.mag file) To download MAGIC :

sudo apt-get install magic

To download KLayout :

  • Click On klayout here: KLAYOUT(https://www.klayout.de/build.html)
  • Download the appropriate version of klayout ; it depends on your operating system.
  • Open it & Install Klayout

To check whether all tools are installed : Try for checkpoint

Checkpoint1 : Type ngspice for ngspice; Give command z3 --help for z3 solver ; Give command python3 for python.

Now next we need to work on python virtual environment: Using the following commands we can work on python virtual environment

python3 -m venv my-librecell-env

source ./my-librecell-env/bin/activate

Installing libre-cell

Now we need to install librecell from git . Commands to download & install :

git clone https://codeberg.org/tok/librecell.git
cd librecell

cd librecell-common
python3 setup.py develop
cd ..

cd librecell-layout
python3 setup.py develop
cd ..

cd librecell-lib
python3 setup.py develop
cd ..

Checkpoint 2: To make sure that llibrecell is installed or not use command : librecell --h

If terminal is showing information or help commands then librecell is installed.

Next we need to deal with actual files that is spice netlist files, tech files, directories,etc. We need to make directory in lbrecell layout folder. Make sure that you are in librecell folder right now [From librecell folder we will go to librecell-layout]

cd librecell-layout

Make directory :

mkdir /tmp/mylibrary`

Conversion command

lclayout --output-dir [Here your output will be stored] --tech [design_tech_file.py] --netlist [Spice_netlist.sp] --cell [Cell_Name]

For example : Use dummy_tech.py file as design tech file.Use AND2X1.sp OR AND4.sp as spice netlist file. Use corresponding cell name ex: --cell AND2X1 OR --cell AND4.

File name must be with location of file. Ex : If my all files are stored in Desktop then I will use

lclayout --output-dir /home/user/Desktop --tech /home/user/Desktop/librecell_tech.py --netlist /home/user/Desktop/cells.sp --cell AND4

OR

lclayout --output-dir /tmp/mylibrary --tech examples/dummy_tech.py --netlist examples/cells.sp --cell AND2X1

MAGIC Layout

Checkpoint 3 :

To make sure MAGIC is installed make a file of magic using magic checkpoint3.mag If MAGIC with blank project is opened then MAGIC is installed.

To make sure klayout is installed give command klayout -h

i. AND2X1 : I have used AND2X1 Sspice netlist & cell to generate layout of AND2X1.

Use command to generate layout

magic AND2X1.mag

Output AND2X1 :

ii. AND4 : I have used AND4 spice netlist & cell name to generate layout of AND4.

magic AND4.mag

Ouput AND4 :

[Hit CTRL if cursor is blinking again & again & Make sure that ouput gd files is stored on Desktop]

Klayout :

i. AND2X1 Klayout : To view klayout of circuit use following command :

klayout AND2X1.gds

Output AND2X1 Klayout : 

ii. AND4 Klayout :

Use following command :

klayout AND4.gds

Output AND4 Klayout :

PROJECT RESOURCES