FABulous Configuration Variables

FABulous can use environment variables to configure options, paths and projects. We distinguish between two types of environment variables: global and project specific environment variables.

• Global environment variables are used to configure FABulous itself. They always start with FAB_.

• Project specific environment variables are used to configure a specific FABulous project. They always start with FAB_PROJ_.

All environment variables can be set in the shell before running FABulous or can be set via .env files.

.env File Locations

Scope	Location	How to use
User global	~/.config/FABulous/.env	Created automatically or manually
Global (explicit)	Any path	Pass via --globalDotEnv CLI argument
Project (auto-detected)	<project_dir>/.FABulous/.env	Placed inside your project
Project (explicit)	Any path	Pass via --projectDotEnv CLI argument

Note

Environment variables set in the shell always have the highest priority, followed by project-specific .env files, then global .env files.

Global Environment Variables

Variable	Environment Variable	Type	Default	User Value	Description
user_config_dir	FAB_USER_CONFIG_DIR	Path	(dynamic)	/path/to/file	-
oss_cad_suite	FAB_OSS_CAD_SUITE	Path	None	/path/to/file	-
yosys_path	FAB_YOSYS_PATH	Path	yosys	/path/to/file	-
nextpnr_path	FAB_NEXTPNR_PATH	Path	nextpnr-generic	/path/to/file	-
iverilog_path	FAB_IVERILOG_PATH	Path	iverilog	/path/to/file	-
vvp_path	FAB_VVP_PATH	Path	vvp	/path/to/file	-
ghdl_path	FAB_GHDL_PATH	Path	ghdl	/path/to/file	-
klayout_path	FAB_KLAYOUT_PATH	Path	klayout	/path/to/file	-
openroad_path	FAB_OPENROAD_PATH	Path	openroad	/path/to/file	-
fabulator_root	FAB_FABULATOR_ROOT	Path	None	/path/to/file	-
models_pack	FAB_MODELS_PACK	Path	None	/path/to/file	-
switch_matrix_debug_signal	FAB_SWITCH_MATRIX_DEBUG_SIGNAL	bool	False	true / false	-
editor	FAB_EDITOR	str	None	any string	-
verbose	FAB_VERBOSE	int	0	1, 2	-
debug	FAB_DEBUG	bool	False	true / false	-
pdk_root	FAB_PDK_ROOT	Path	None	/path/to/file	-
pdk	FAB_PDK	str	None	any string	-
pdk_hash	FAB_PDK_HASH	str	None	any string	-
fabric_die_area	FAB_FABRIC_DIE_AREA	tuple	(0, 0, 1000, 1000)	[0, 0, 1000, 1000]	-
windows_warning_acknowledged	FAB_WINDOWS_WARNING_ACKNOWLEDGED	bool	False	true / false	-

Project Specific Environment Variables

Variable	Environment Variable	Type	Default	User Value	Description
proj_dir	FAB_PROJ_DIR	Path	(dynamic)	/path/to/file	-
proj_lang	FAB_PROJ_LANG	HDLType	HDLType.VERILOG	verilog, vhdl, sv	-
proj_version_created	FAB_PROJ_VERSION_CREATED	Version	0.0.1	1.2.3	-
proj_version	FAB_PROJ_VERSION	Version	-	1.2.3	-

Interactive CLI Settables

These variables can be set and get interactively in the FABulous CLI using the set and get commands.

Usage:

FABulous> set <variable> <value>
FABulous> get <variable>

Variable	Type	Description
projectDir	Path	The directory of the project
csvFile	Path	The fabric file
verbose	bool	verbose output
force	bool	force execution