title: add_pdn_ring(2)
date: 24/09/08
NAME
add_pdn_ring - add pdn ring
SYNOPSIS
add_pdn_ring -layers layer_name -widths width_value|list_of_2_values -spacings spacing_value|list_of_2_values [-grid grid_name] [-core_offsets offset_value] [-pad_offsets offset_value] [-add_connect] [-extend_to_boundary] [-connect_to_pads] [-connect_to_pad_layers layers] [-starts_with POWER|GROUND] [-nets list_of_nets] [-ground_pads pads] [-power_pads pads]
DESCRIPTION
The add_pdn_ring command is used to define power/ground rings around a grid region.
The ring structure is built using two layers that are orthogonal to each other.
A power/ground pair will be added above and below the grid using the horizontal
layer, with another power/ground pair to the left and right using the vertical layer.
Together these 4 pairs of power/ground stripes form a ring around the specified grid.
Power straps on these layers that are inside the enclosed region are extend to
connect to the ring.
Example usage:
add_pdn_ring -grid main_grid -layer {metal6 metal7} -widths 5.0 -spacings 3.0 -core_offset 5
OPTIONS
-layers: Specifies the name of the layer for these stripes.
-widths: Value for the width of the stdcell rail.
-spacings: Optional specification of the spacing between power/ground pairs within a single pitch. (Default: pitch / 2).
-grid: Specifies the name of the grid to which this ring defintion will be added. (Default: Last grid created by define_pdn_grid).
-core_offsets: Value for the offset of the ring from the grid region.
-pad_offsets: When defining a power grid for the top level of an SoC, can be used to define the offset of ring from the pad cells.
-add_connect: Automatically add a connection between the two layers.
-extend_to_boundary: Extend the rings to the grid boundary.
-connect_to_pads: The core side of the pad pins will be connected to the ring.
-connect_to_pad_layers: Restrict the pad pins layers to this list.
-starts_with: Specifies whether the first strap placed will be POWER or GROUND (Default: grid setting).
-nets: Limit straps to just this list of nets.
ARGUMENTS
This command has no arguments.