diff --git a/icetime/Makefile b/icetime/Makefile
index b1cd18d..f268b99 100644
--- a/icetime/Makefile
+++ b/icetime/Makefile
@@ -8,6 +8,8 @@ endif

 all: icetime$(EXE)

+CHIPS=lp384 lp1k lp8k hx1k hx8k up5k
+
 ifeq ($(EXE),.js)
 icetime$(EXE): | share/$(CHIPDB_SUBDIR)/chipdb-384.txt share/$(CHIPDB_SUBDIR)/chipdb-1k.txt share/$(CHIPDB_SUBDIR)/chipdb-8k.txt share/$(CHIPDB_SUBDIR)/chipdb-5k.txt

@@ -26,11 +28,11 @@ share/$(CHIPDB_SUBDIR)/chipdb-5k.txt: ../icebox/chipdb-5k.txt
 override LDFLAGS += --embed-file share
 endif

-icetime$(EXE): icetime.o iceutil.o
+icetime$(EXE): icetime.o iceutil.o $(addsuffix .o, $(addprefix timings-, $(CHIPS)))
 	$(CXX) -o $@ $(LDFLAGS) $^ $(LDLIBS)

-icetime.o: icetime.cc timings.inc
-iceutil.o: iceutil.cc
+timings-%.cc: timings.py ../icefuzz/timings_*.txt
+	python3 timings.py $* > timings-$*.cc

 timings.inc: timings.py ../icefuzz/timings_*.txt
 	python3 timings.py > timings.inc.new
diff --git a/icetime/icetime.cc b/icetime/icetime.cc
index e7c0cd7..2feedfe 100644
--- a/icetime/icetime.cc
+++ b/icetime/icetime.cc
@@ -746,7 +746,12 @@ const std::set<std::string> &get_inports(std::string cell_type)
 	return inports_map.at(cell_type);
 }

-#include "timings.inc"
+double get_delay_lp384(std::string cell_type, std::string in_port, std::string out_port);
+double get_delay_lp1k(std::string cell_type, std::string in_port, std::string out_port);
+double get_delay_lp8k(std::string cell_type, std::string in_port, std::string out_port);
+double get_delay_hx1k(std::string cell_type, std::string in_port, std::string out_port);
+double get_delay_hx8k(std::string cell_type, std::string in_port, std::string out_port);
+double get_delay_up5k(std::string cell_type, std::string in_port, std::string out_port);

 double get_delay(std::string cell_type, std::string in_port, std::string out_port)
 {
diff --git a/icetime/timings.py b/icetime/timings.py
index 7ac2a7b..604dbcd 100644
--- a/icetime/timings.py
+++ b/icetime/timings.py
@@ -1,8 +1,10 @@
 #!/usr/bin/env python3

 import re
+import sys

 print("// auto-generated by timings.py from ../icefuzz/timings_*.txt")
+print("#include <string>")

 def timings_to_c(chip, f):
     print("")
@@ -47,6 +49,11 @@ def timings_to_c(chip, f):
     print("  exit(1);")
     print("}")

-for db in "lp384 lp1k lp8k hx1k hx8k up5k".split():
+if len(sys.argv) >= 2:
+	chips = sys.argv[1:]
+else:
+	chips = "lp384 lp1k lp8k hx1k hx8k up5k".split()
+
+for db in chips:
     with open("../icefuzz/timings_%s.txt" % db, "r") as f:
         timings_to_c(db, f);