It is important to go through the LEF fileĪnd change all the cell names back to lower case (in the MACROS section of the file) so When importing the design back into Virtuoso. Library (both have layout and abstract versions of the cells), but causes problems To upper case, which is good for differentiating the SE and Virtuoso views in the
#Cadence virtuoso layout 100 pins generator
Abstract Generator also changes the name of every cell Makes all rows of the smallest-dimension SITE declared the the LEF file, which Type as the Row in which it will be placed. Each cell must have a SITE associated with it of the same It works best with low-level standard cells that strictly follow the but it practice it takes a bit of tweaking to get everything to come out Initialize the floorplan (cell dimensions, number of rows.Load the design ( def file from Virtuoso).
Load the design library ( lef file from Abstract Generator) To place cells quickly and efficiently, but it has it's limitations. Silicon Ensemble is an auto-place and route tool by Cadence. Layout in Virtuoso ( Edit -> Other -> Move Origin) and in the MACRO definition of theĬell in the LEF file (this is also corrected when you run the perl script lef_corrections). Make sure that the origin of each cell is (0,0), both when you perform If this is not true, you can either modify the script or manuallyĪ shorter Note: Sometimes the origins of larger cells get shifted WARNING: The lef_corrections script assumes that all of you Virtuoso cell namesĬontain no UPPER CASE letters. This will not change your old lef file, but will create a new one (new_file_name.lef) with Lef_corrections your_file_name.lef > new_file_name.lef Copy the script into the directory in which your cifįile resides and run it from the unix command line by typing We've written a perl script which will edit the file for you called lef_corrections. LEF file are in the MACRO definition for that cell, found at the end of the file.
The only place the name file for a particular cell occur in the The LEF names must agree exactly with those in the DEF file for SE place-and-route Inv specified in the DEF file is the same as the INV described
Lower-case cell names used in Virtuoso (and the DEF file created above). Need to go back and replace these capitalized names (in the LEF file exportedįrom Abstract Generator in the last tutorial) with the original, Because Cadence is case sensitive, you will Long Note: The abstract views created in the Abstract Generator Sure you have completed the previous tutorial on Silicon Ensemble's Abstract You need to have an abstract view that Silicon Ensemble can understand. This script strips out refereces to power and ground nets because they are routed differently than normal nets (usually through abutment).īefore you can import the design into Silicon Ensemble for place and route, Some of those changes are performed by the perl script def_correction. There are a few modifications that need to be made to this file before it will suceed in place-and-route. YouĬan view it with a text editor if you choose. Thisįile contains a list of subcells in the design and netlist information. This will place a Design Exchange Format file in your cadence directory. Click on File -> Export -> DEF.įill out the following form as appropriate Now we can export the design to be routed. Double check your basicĬells and if you choose to proceed, be wary or errors. Is having an improper routing grid in your design. The most common error is that you didn't set Cell If you see overlapping, there might be something wrong with Open " autoLayout" view of adder for editing.Ĭomment: All the cells should be stacked with order inside the default This will generate an " autoLayout" view for the combinational logic. Make sure Run is " Generate Physical Hierarchy
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