XSCHEM SCHEMATIC EDITOR

Current distribution version 3.4.8.0

Precompiled for 64b 24.04 Ubuntu and Ubuntu-based Linux. It's tested on a Ubuntu 24.04 on AWS Lightsail. If you are interested in compiling from the source, instructions in ADMIN.md:Compiling and Installing should help.

Xschem is a schematic capture program, it allows creation of hierarchical representation of circuits with a top down approach . A VHDL or Verilog or Spice netlist can be generated from the drawn schematic, allowing the simulation of the circuit. Key feature of the program is its drawing engine written in C and using directly the Xlib drawing primitives; this gives very good speed performance, even on very big circuits. The user interface is built with the Tcl-Tk toolkit, tcl is also the extension language used. Allows launching NGSpice from the schematic editor. Easy to create new symbols with netlist property.

Downloading & Setting Up XSchem

• Change directory cd to install directory <INSTALL_DIR> e.g. /home/user/cad

• To download from the git repository:

  • git clone https://github.com/silicon-vlsi-org/eda-xschem

• Change directory to the installed directory eg. cd eda-xschem

• Checkout the desired version: git checkout v3.4.8.0

  • To make sure you are on the right version type git branch and your output should have a line like this :
  • * (HEAD detached at v3.4.8.0)

• Add the following environment variables in your ~/.bashrc (NOTE: The path below is an example, make sure it matches your particular path)

export XSCHEM_HOME=$HOME/cad/eda-xschem/glnxa64
export XSCHEM_SHAREDIR=$XSCHEM_HOME/share/xschem
export PATH=$PATH:$XSCHEM_HOME/bin

Quick Start Guide

• User Manual/Tutorials: [ PDF | HTML | MAN]
• Analog simulation with xschem and the skywater 130nm Process Development Kit (PDK): YouTube tutorial by Stephan
• Create a file xschemrc in the work directory (say ~/work/xschem) with the following tcl initilizations:

set PDK_ROOT "$env(HOME)/share/pdk/"  ;# Default open_pdks location
set PDK "sky130A"
append XSCHEM_LIBRARY_PATH ":${PDK_ROOT}/${PDK}/libs.tech/xschem"
source $PDK_ROOT/$PDK/libs.tech/xschem/xschemrc

NOTE The above content is in the file xschemrc in this repo

• Start xschem from the work directory
• xschem should start with a SKY130 schematic with the lots of examples and working schematic.
• Choose a test circuit eg. test_inv
• Generate a netlist by clicking the Netlist button.
• The netlist is created in the default driectory ~/.xschem/simulations
• If you are using the SKY130 PDK, create ~/.xschem/simulations/.spiceinit with the following content to speed up the simulation:

set ngbehavior=hsa
set ng_nomodcheck

NOTE The above content is in the file spicinit in this repo

Release History

• v3.4.8.0
  • xschem v3.4.8 on 05/16/2025
  • Compiled for Ubuntu 24.04
  • This version is minimum requirement for SKY130 PDK integration
• v2.9.9.0
  • xschem v2.9.9 on 06/17/2021
  • Compiled for Ubuntu 18.04

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