diff --git a/compiler/characterize_existing.py b/compiler/characterize_existing.py
new file mode 100755
index 00000000..82e95b1b
--- /dev/null
+++ b/compiler/characterize_existing.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+# See LICENSE for licensing information.
+#
+# Copyright (c) 2016-2021 Regents of the University of California and The Board
+# of Regents for the Oklahoma Agricultural and Mechanical College
+# (acting for and on behalf of Oklahoma State University)
+# All rights reserved.
+#
+"""
+This script will characterize an SRAM previously generated by OpenRAM given a
+configuration file. Configuration option "use_pex" determines whether extracted
+or generated spice is used and option "analytical_delay" determines whether
+an analytical model or spice simulation is used for characterization.
+"""
+
+import sys
+import datetime
+from globals import *
+from importlib import reload
+
+(OPTS, args) = parse_args()
+
+# Override the usage
+USAGE = "Usage: {} [options] <config file>\nUse -h for help.\n".format(__file__)
+
+# Check that we are left with a single configuration file as argument.
+if len(args) != 1:
+    print(USAGE)
+    sys.exit(2)
+
+# These depend on arguments, so don't load them until now.
+import debug
+
+# Parse config file and set up all the options
+init_openram(config_file=args[0], is_unit_test=False)
+
+# Configure the SRAM organization (duplicated from openram.py)
+from sram_config import sram_config
+c = sram_config(word_size=OPTS.word_size,
+                num_words=OPTS.num_words,
+                write_size=OPTS.write_size,
+                num_banks=OPTS.num_banks,
+                words_per_row=OPTS.words_per_row,
+                num_spare_rows=OPTS.num_spare_rows,
+                num_spare_cols=OPTS.num_spare_cols)
+
+# Initialize and create the sram object
+from sram import sram
+s = sram(name=OPTS.output_name, sram_config=c)
+s.create()
+
+# Characterize the design
+start_time = datetime.datetime.now()
+from characterizer import lib
+debug.print_raw("LIB: Characterizing... ")
+lib(out_dir=OPTS.output_path, sram=s.s, sp_file=s.get_sp_name())
+print_time("Characterization", datetime.datetime.now(), start_time)
+
+# Output info about this run
+print("Output file is:\n{0}.lib".format(OPTS.output_path))
+#report_status() #could modify this function to provide relevant info
+
+# Delete temp files, remove the dir, etc.
+end_openram()
diff --git a/compiler/sram/sram.py b/compiler/sram/sram.py
index afd57f48..fdc8ec76 100644
--- a/compiler/sram/sram.py
+++ b/compiler/sram/sram.py
@@ -25,6 +25,7 @@ class sram():
 
         self.name = name
         self.config = sram_config
+        sram_config.setup_multiport_constants()
         sram_config.set_local_config(self)
 
         self.sp_name = OPTS.output_path + self.name + ".sp"
@@ -120,6 +121,8 @@ class sram():
         start_time = datetime.datetime.now()
         debug.print_raw("SP: Writing to {0}".format(self.sp_name))
         self.sp_write(self.sp_name)
+
+        # Save a functional simulation file with default period
         functional(self.s,
                    os.path.basename(self.sp_name),
                    cycles=200,
@@ -164,8 +167,6 @@ class sram():
             verify.run_pex(self.s.name, self.gds_name, self.sp_name, output=self.pex_name)
             print_time("Extraction", datetime.datetime.now(), start_time)
 
-        # Save a functional simulation file
-
         # Characterize the design
         start_time = datetime.datetime.now()
         from characterizer import lib