SNL Keyword Reference

Keywords used in TYPE and PART statements within Simic Network Language files.

Structural Keywords

Keywords that define circuit topology and pin connections.

Keyword Alias Function
PART P Specifies instance name for a component (PART statements only).
TYPE T Defines macro name (TYPE) or references a type (PART).
INPUTS I, IPIN, INET Lists input pins (TYPE) or signals (PART).
OUTPUTS O, OPIN, ONET Lists output pins (TYPE) or signals (PART).
BUSSES B, BPIN, BNET Lists bidirectional pins (TYPE) or signals (PART).
COMPOSITION COMP Specifies abstraction level (MACRO, BOOLEAN, BEHAVIORAL).
BOOLEAN — Functional specification using Boolean equations (requires BEGIN/END block).
STATE — Declares state variables for BOOLEAN types.

Delay & Timing Keywords

Keywords for specifying propagation delays using global or local specifications.

Keyword Alias Function
OUTPUT-DELAY ODEL References global delay for output rise/fall.
BUS-DELAY BDEL References global delay for bus rise/fall.
OUTPUT-RISE ORISE Local output rise delay specification.
OUTPUT-FALL OFALL Local output fall delay specification.
OUTPUT-CHANGE OCHANGE Local output delay when rise and fall are equal.
BUS-RISE BRISE Local bus rise delay specification.
BUS-FALL BFALL Local bus fall delay specification.
BUS-CHANGE BCHANGE Local bus delay when rise and fall are equal.
TIMING-CHECKS — Specifies setup, hold, and pulse-width parameters for flip-flops/latches.

Loading Keywords

Keywords for specifying pin capacitance values.

Keyword Alias Function
INPUT-LOADS ILOD Specifies input pin capacitance.
OUTPUT-LOADS OLOD Specifies output pin self-loading (driver's own capacitance).
BUS-LOADS BLOD Specifies bidirectional pin capacitance.

Drive Strength Keywords

Keywords for controlling output drive capability.

Keyword Alias Function
OUTPUT-DRIVE ODRIVE Sets both high and low output drive strength.
OUTPUT-HDRIVE OHDRIVE Sets high-level output drive strength.
OUTPUT-LDRIVE OLDRIVE Sets low-level output drive strength.
BUS-DRIVE BDRIVE Sets both high and low bus drive strength.
BUS-HDRIVE BHDRIVE Sets high-level bus drive strength.
BUS-LDRIVE BLDRIVE Sets low-level bus drive strength.

Signal Behavior Keywords

Keywords for decay times, wire-tie resolution, and spike control.

Keyword Alias Function
OUTPUT-DECAY ODEC, ODECAY Time for output to decay to hi-Z state.
BUS-DECAY BDEC, BDECAY Time for bus to decay to hi-Z state.
OUTPUT-DOMINANCE ODOM Wire-tie behavior: 0=wired-AND, 1=wired-OR, X=conflict.
BUS-DOMINANCE BDOM Wire-tie behavior for busses.
OUTPUT-FILTER OFILTER Spike filter parameter (percentage or absolute).
BUS-FILTER BFILTER Spike filter parameter for busses.
OUTPUT-LIBERAL OLIBERAL Liberal parameter delays X-state propagation.
BUS-LIBERAL BLIBERAL Liberal parameter for busses.
INPUT-HIZ IHIZ How to treat floating inputs: 0, 1, or X.

Special Purpose Keywords

Keywords for switches, memories, and primitive-specific attributes.

Keyword Alias Function
SERIES-DEPTH SDEPTH ON-resistance for resistive switches (1-32766).
LASTADDR — Last valid address for RAM/ROM primitives.

Physical Attribute Keywords

Keywords for place-and-route programs (informational only, ignored by SIMIC).

Keyword Alias Function
PADS — Number of physical pads for the cell.
TRANSISTORS TRANS Number of transistors in the cell.
WIDTH W Cell width (standard cells) or gate count (gate arrays).
INPUT-PADS IPAD Placement location for input pads.
OUTPUT-PADS OPAD Placement location for output pads.
BUS-PADS BPAD Placement location for bidirectional pads.
AUX-PINS A, APIN Auxiliary pins such as VDD, VSS.
AUX-PADS APAD Placement location for auxiliary pads.

Annotation Keywords

Keywords for adding comments and remarks to SNL descriptions.

Keyword Alias Function
COMMENT C, COM Comment to end of physical line (not displayed during compilation).
REMARK R, REM Comment displayed during circuit compilation.

Abbreviation Rules

SIMIC recognizes any valid abbreviation of keywords, ranging from the minimum abbreviation shown above to the full keyword. Keywords with hyphens (e.g., OUTPUT-DELAY) can be abbreviated by omitting the hyphen and truncating (e.g., ODEL, ODELA, ODELAY are all valid).

Minimum abbreviation lengths are typically 4 characters or less to prevent ambiguity. For example, ODEL is the minimum for OUTPUT-DELAY because ODE could be ambiguous with ODECAY.