I am trying to add DFFRAM from the the caravel system to my own design but I am getting this error. 8.3. Executing AST frontend in derive mode using pre-parsed AST for module `\DFFRAM'. ERROR: Module `\sky130_fd_sc_hd__clkbuf_4' referenced in module `\DFFRAM' in cell `\DOBUF[31]' is not part of the design. How do I add the reference to the cell? Any assistance would be appreciated..

set ::env(SYNTH_READ_BLACKBOX_LIB) 1

add this in config.tcl @Andy Attwood

I had that set. Tis solved the problem set ::env(LIB_SYNTH) [glob /disk2/openlane/pdks/sky130A/libs.ref/sky130_fd_sc_hd/lib/sky130_fd_sc_hd__tt_100C_1v80.lib]

That's strange. This variable is set by default so there shouldn't be a need to explicitly declare it.