In recent versions you can drive spectre using VCD (Verilog Change Dump), EVCD (Extended Verilog Change Dump) or Vector files. These are digital stimulus files. However, you'd need to be using spectre from MMSIM60 or MMSIM61 (if my memory is correct), and also an IC5141 version to provide this via the Setup->Environment form.

You can't use Verilog code (assuming this is normal digital Verilog) to drive spectre, since spectre is an analog simulator. If it was Verilog-A, you'd be OK. If you're using a mixed signal simulator such as AMS Designer (or the older spectre-verilog mixed-signal simulator) then you could use Verilog stimulus...

Regards,

Andrew.