Innovus Block Implementation Flashcards
What is the technology LEF
Read during design import, contains
1) routing rules, drc checks needed for detail route, standard cell pin locations, and for gcell creation
2) site definitions to create placement rows and for overlap of cells
What are the properties of a routing track?
1) offset, 2) pitch, 3) direction
given in tlef
what are placement rows?
multiple of a site from the tlef, think of a site as one row, should be Y symmetric
What is a site?
The minimum unit of placement. It represents a slot where a cell can be placed.
What are the placement types of a cell?
Core and IO
What are the four types on constraints?
None, Soft Guide, Guide, Region and Fence
What is a soft guide
same as guide but no fixed locations
What is a guide
module is preplaced in the core design area
What is a region
Forces all modules to be placed within a region but allows instances from other modules as well
What is a fence
all modules must be placed within the region and no other modules are allowed inside. a module becomes a fence when it is specified as a partition
What is TU
target utilization, a measurement of area, takes into account cell and macro area
What is EU
effective utilization, a measurement of area, like TU but also looks at blockages
How to fix an object
change place_status to fixed, it can be upsized by optimization. boundary will be a bold line
What is a placement halo?
prevents placement of blocks and standard cells around this block. used to prevent congestion and to make it easier to route in and out of block. moves with block
What is a routing halo?
Area around block used to help SI. Only straight routes to block pins are allowed through routing halo
How to create a physical hierarchy within modules
create_group and then update_group to add objects & instances then crate_logic_hierarchy to commit
What are tieoff cells?
Physical cells that implement 1’b0/1
What is a well tap
Used to prevent latchup (add_well_taps)
What is a endcap?
cells at end of rows to handle end-of-row well tie-off requirements (add_endcaps)
What is a filler?
Use to maintain continuity between cells in row of diffusion layout. (set_db add_fillers_prefix and add_fillers)
What is decap
capacitor cells used to bypass vdd and vss metal rows (add_decaps)
How to add cells physical cells in a pattern?
to tap and decap use: add_physical_cell
What is ring and stripes?
A power methodology where each block has it’s own ring structure and its own stripes that connect to the top block. rings can be shared by abutted blocks
TCL to check floorplan
check_floorplan
