Xcircuit 3.6 series brings on technology library support, which enables anyone to maintain customed analog or digital IPs, independent of the schematic design. This powerful feature, coupled with ngspice, helps the designer to maintain their spice commands within the testbench schematic. It will automatically extracts the spice netlists with the subcircuits included, then from the tcl console simulate the design.
However this was not working out of the box and the user needed to patch ngspice. Since ngspice rework 17, Fedora’s ngspice was patched accordingly. But with ngspice rework 19, it broke. This week Holger Volgt improved the patch and merge it to ngspice cvs branch.
This blog post will briefly show a testcase about how to invoke ngspice within Xcircuit directly.
Launch Xcircuit and load your design. Here, I’ll take a simple invertor as example. Then launch the Tcl console from the file menu and type
::xcircuit::spice start
If you encounter this error, you are certainly using an older version of ngspice.
There is already an update in the fedora repositories which fixes this issue.
On the screenshot below, you can see the invertor in a test situation alongside spice commands for the simulation. Hence there is no need to maintain extra file or makefile to launch SPICE simulation. Everything is launched and saved by Xcircuit in a postscript format.
::xcircuit::spice start
(extracts the spice netlist and sets the initial condiction.)
::xcircuit::spice run
(executes the simulation)
::xcircuit::spice send “plot v(Vin) v(Vout)”
(sends the plot command to ngspice and displays the plot)
Arun SAG has recently filed a package review request for emacs-spice-mode. Once approved and pushed to Fedora repositories, you can execute spice simulations within emacs as well.
Filed under: asic, emacs, feature, fedora, Free Electronic Lab, IP, xcircuit
Chitlesh Goorah
