Variables information

This page describes configuration variables and list the defaults for skywater130 pdk.

Required variables

VariableDescription
DESIGN_NAMEThe name of the top level module of the design
VERILOG_FILESThe path of the design's verilog files
CLOCK_PERIODThe clock period for the design in ns
CLOCK_PORTThe name of the design's clock port

Optional variables

These variables are optional that can be specified in the design configuration file.

Synthesis

VariableDescription
LIB_SYNTHThe library used for synthesis.
(Default: ./platform/skywater130/scs8lp_ss_1.65v_-40C.lib)
SYNTH_DRIVING_CELLThe cell to drive the input ports.
(Default: scs8lp_inv_8)
SYNTH_CAP_LOADThe capacitive load on the output ports in femtofarads.
(Default: 24.36 ff)
SYNTH_MAX_FANOUTThe max load that the output ports can drive.
(Default: 5 cells)
SYNTH_MAX_TRANSThe max transition time (slew) from high to low or low to high on cell inputs in ns. Used in synthesis
(Default: Calculated at runtime as 10% of the provided clock period)
SYNTH_STRATEGYStratgies for abc logic synthesis and technology mapping
Possible values are 0, 1 (delay), 2, and 3 (area)
(Default: 0)
LIB_MINLibrary used for min delay calculation during STA.
(Default:./platform/skywater130/scs8lp_ss_1.65v_-40C.lib)
LIB_MAXLibrary used for max delay calculation during STA.
(Default:./platform/skywater130/scs8lp_ff_1.65v_-40C.lib)
LIB_TYPICALLibrary used for typical delay calculation during STA.
(Default./platform/skywater130/scs8lp_ss_1.65v_-40C.lib:)

Floorplanning

VariableDescription
FP_CORE_UTILThe core utilization percentage.
(Default: 50 percent)
FP_ASPECT_RATIOThe core's aspect ratio (height / width).
(Default: 1)
FP_CORE_MARGINThe length of the margin surrounding the core area.
(Default: 3.36 microns)
FP_IO_HMETALThe metal layer on which to place the io pins horizontally (top and bottom of the die).
(Default: 3)
FP_IO_VMETALThe metal layer on which to place the io pins vertically (sides of the die)
(Default: 2)
FP_WELLTAP_CELLThe name of the welltap cell during welltap insertion.
(Default: scs8lp_tap_1)
FP_ENDCAP_CELLThe name of the endcap cell during endcap insertion.
(Default: scs8lp_decap_3)
FP_PDN_VOFFSETThe offset of the vertical power stripes on the metal layer 4 in the power distribution network
(Default: 16.32)
FP_PDN_VPITCHThe pitch of the vertical power stripes on the metal layer 4 in the power distribution network
(Default: 153.6)
FP_PDN_HOFFSETThe offset of the horizontal power stripes on the metal layer 5 in the power distribution network
(Default: 16.65)
FP_PDN_HPITCHThe pitch of the horizontal power stripes on the metal layer 5 in the power distribution network
(Default: 153.18)

Placement

VariableDescription
PL_TARGET_DENSITYThe desired placement density of cells. It reflects how spread the cells would be on the core area. 1 = closely dense. 0 = widely spread
(Default: 0.4)
PL_TIME_DIRVENSpecifies whether the placer should use time driven placement. 0 = false, 1 = true
(Default: 0)
PL_LIBSpecifies the library for time driven placement
(Default: LIB_TYPICAL)

CTS

VariableDescription
CTS_TARGET_SKEWThe target clock skew in picoseconds.
(Default: 20 ps)
CTS_ROOT_BUFFERThe name of cell inserted at the root of the clock tree.
(Default: scs8lp_clkbuf_16)
CTS_TECH_DIRThe directory of look-up-tables for tirtonCTS.
(Default: ./platforms/skywater130/TritonCTS)
CTS_TOLERANCEan integer value that represents a tradeoff of QoR and runtime. Higher values will produce smaller runtime but worse QoR
(Default: 100)

Fillcell Insertion

VariableDescription
FILL_INSERTIONenable

Routing

VariableDescription
GLB_RT_MAXLAYERThe number of highest layer to be used in routing.
(Default: 6)
GLB_RT_ADJUSTMENTReduction in the routing capacity of the edges between the cells in the global routing graph. Values range from 0 to 1.
(Default: 0.15)
GLB_RT_LI1_ADJUSTMENT
GLB_RT_MET1_ADJUSTMENT

Misc

VariableDescription
PDKSpecifies the process design kit (pdk).
(Default: skywater130 )
PDK_VARIANTSpecifies the process design kit (pdk) variant.
(Default: scs8lp )
CELL_PADCell padding; increases the width of cells.
(Default: 0.96 microns -- 2 sites)

Flow control

VariableDescription
RUN_ROUTING_DETAILEDEnables detailed routing. 1 = Enabled, 0 = Disabled
(Default: 1)
RUN_MAGICEnables running magic and GDSII streaming.1 = Enabled, 0 = Disabled
(Default: 0)
CLOCK_TREE_SYNTHEnables cts.1 = Enabled, 0 = Disabled
(Default: 0)
FILL_INSERTIONEnables fill cells insertion after cts (if enabled) .1 = Enabled, 0 = Disabled
(Default: 0)