How to use RCX rules to be used during routing

[titan73]

I didn't use any RCX tech rules files before as I was focusing on routing.
I generated them and now I'd like to take them into account during routing.

I grepped into ORFS and found:

docs/user/FlowVariables.md:| <a name="RCX_RULES"></a>RCX_RULES| RC Extraction rules file path.| |
docs/user/FlowVariables.md:- [RCX_RULES](#RCX_RULES)
flow/util/makeIssue.sh:                             RCX_RULES \
flow/scripts/final_report.tcl:  [env_var_exists_and_non_empty RCX_RULES]
flow/scripts/final_report.tcl:  extract_parasitics -ext_model_file $::env(RCX_RULES)
flow/scripts/variables.yaml:RCX_RULES:
flow/platforms/nangate45/config.mk:export RCX_RULES               = $(PLATFORM_DIR)/rcx_patterns.rules
flow/platforms/ihp-sg13g2/config.mk:export RCX_RULES = $(PLATFORM_DIR)/rcx_patterns.rules
flow/platforms/sky130hs/config.mk:export RCX_RULES = $(PLATFORM_DIR)/rcx_patterns.rules
flow/platforms/asap7/openlane/config.tcl:set ::env(RCX_RULES) "$::env(PDK_ROOT)/$::env(PDK)/libs.tech/openlane/rcx_patterns.rules"
flow/platforms/asap7/config.mk:export RCX_RULES               = $(PLATFORM_DIR)/rcx_patterns.rules
flow/platforms/sky130hd/config.mk:export RCX_RULES = $(PLATFORM_DIR)/rcx_patterns.rules
flow/platforms/gf180/config.mk:export BC_RCX_RULES                           = $(PLATFORM_DIR)/openROAD/rcx/gf180mcu_1p5m_1tm_9k_sp_smim_OPTB_bst.rules
flow/platforms/gf180/config.mk:export WC_RCX_RULES                           = $(PLATFORM_DIR)/openROAD/rcx/gf180mcu_1p5m_1tm_9k_sp_smim_OPTB_wst.rules
flow/platforms/gf180/config.mk:export TC_RCX_RULES                           = $(PLATFORM_DIR)/openROAD/rcx/gf180mcu_1p5m_1tm_9k_sp_smim_OPTB_typ.rules
flow/platforms/gf180/config.mk:export RCX_RULES                              = $($(CORNER)_RCX_RULES)

I only see flow/scripts/final_report.tcl: extract_parasitics -ext_model_file $::env(RCX_RULES).
But this only for generating the final report.
How do I use them during routing?

[maliberty]

The are only used for post routing final timing, not during routing.

[maliberty]

From the docs:

| -resistance | Resistance per unit length, units are from the first Liberty file read. |

Note it per length not per square so you should assume your routing width (usually min width).

[titan73]

Ok. So I have to divide the values with the layer default width then. Thanks

[maliberty]

Multiply?

[titan73]

Hum. To get the number of squares the length should be divided by the width. No?

[maliberty]

Nvm