Differences

This shows you the differences between two versions of the page.

--- custom:start [2019/05/04 14:58]
rajit
+++ custom:start [2020/12/02 01:00]
127.0.0.1 external edit
@@ Line 3: / Line 3: @@
 The custom flow is for designing, simulating, and verifying hand-designed/optimized circuits.
-{{ :custom:customflow.png?400 |}}
+{{ :custom:customflow.png?600 |}}
+In the standard custom circuit flow using ACT, there are two basic parts:
+  * Circuit design. This is done via text entry using an [[language:start|ACT]] file. In this file you can specify pull-up and pull-down networks as well as transistor sizes (width/length) and type (e.g. low threshold, high threshold).
+       * This circuit can be converted into a spice netlist using the ''netgen'' tool for analog simulation. This converts a hierarchical ACT design into a hierarchical spice netlist.
+      *  This circuit can be simulated using existing switch-level simulators like ''irsim'' or ''cosmos'' using ''prs2sim'', which converts the hierarchical ACT design into a flat simulation file (''.sim'' and ''.al'') that can be read by ''irsim''/''cosmos''.
+      * Asynchronous gate-level simulation can be done using the ''prsim'' tool.
+   * Circuit layout. We assume that the layout is created using the ''magic'' VLSI layout editor.
+      * The circuit can be '':extract''ed from from ''magic'' to create a ''.ext'' file. This contains the layout information and parasitics.
+      * Magic also permits the creation of a simulation file using the built-in ''ext2sim'' (an external tool in older versions, but a built-in command in version 8.x). This can be simulated using ''irsim''/''cosmos'' as well.
+      * The layout can be compared against the circuit design in two ways:
+           * The existing open-source ''gemini'' tool can be used for strict transistor-level comparison between the ''.sim'' file generated from the layout, and the ''.sim'' file created from the ''.act'' file (''prs2sim'')
+           * The ACT-provided ''lvp'' tool can be used to compare that the layout matches the production rules used to specify the logic. This tool does not check width/length of transistors, but rather checks that the gates are logically equivalent. It also requires all signals to be named consistently in the layout and ACT file.