diff --git a/config.py b/config.py
index e094d86..fb138fd 100644
--- a/config.py
+++ b/config.py
@@ -65,6 +65,8 @@ class Config:
             flow.dreamplace_bin_path = sec.get('dreamplace_bin_path')
         if sec.get('yosys_bin_path'):
             flow.yosys_bin_path = sec.get('yosys_bin_path')
+        if sec.get('cadence_version'):
+            flow.cadence_version = sec.get('cadence_version')
 
         flow.config()
         return flow
diff --git a/demo/config.sample.ini b/demo/config.sample.ini
index e86489d..3edd199 100644
--- a/demo/config.sample.ini
+++ b/demo/config.sample.ini
@@ -33,6 +33,7 @@
 ; liberty_input       str         Path to the input .lib file
 
 ; # External toolkit settings
+; cadence_version     str         15/19
 ; dreamplace_bin_path str         Path/to/DREAMPlace/.../Placer.py
 ; yosys_bin_path      str         Path/to/Yosys/build_dir/, which contains yosys and yosys-abc binaries
 
@@ -58,21 +59,22 @@ lef_input = /home/wxm/cocoon/demo/lib/gscl45nm.lef
 liberty_input = /home/wxm/cocoon/demo/lib/gscl45nm.lib
 
 # External toolkit settings
+cadence_version = 15
 dreamplace_bin_path = /home/wxm/DREAMPlace/install/dreamplace/Placer.py
 yosys_bin_path = /home/wxm/yosys/build
 
 # Flow settings
 flow = {'synth':'genus', 'placement':'innovus', 'routing':'innovus'}
-n_iter_IFT = 1
+n_iter_IFT = 0
 verbose = False
 
-[ALU(Chisel)]
+[gcd-test]
 # Design settings
-design_name = AluTop
-is_Chisel_design = True
+design_name = gcd
+is_Chisel_design = False
 rtl_input = /home/wxm/cocoon/demo/gcd/gcd.v
 Chisel_input = /home/wxm/cocoon/demo/alu-chisel/
-result_dir = /home/wxm/cocoon/results/
+result_dir = /home/wxm/cocoon/results/test/
 clk_name = clk
 delay = 1000
 
@@ -82,12 +84,38 @@ lef_input = /home/wxm/cocoon/demo/lib/gscl45nm.lef
 liberty_input = /home/wxm/cocoon/demo/lib/gscl45nm.lib
 
 # External toolkit settings
+cadence_version = 15
 dreamplace_bin_path = /home/wxm/DREAMPlace/install/dreamplace/Placer.py
 yosys_bin_path = /home/wxm/yosys/build
 
 # Flow settings
-flow = {'synth':'yosys', 'placement':'dreamplace', 'routing':'innovus'}
+flow = {'synth':'genus', 'placement':'innovus', 'routing':'innovus'}
 n_iter_IFT = 0
 verbose = False
 
 
+; [ALU(Chisel)]
+; # Design settings
+; design_name = AluTop
+; is_Chisel_design = True
+; rtl_input = /home/wxm/cocoon/demo/gcd/gcd.v
+; Chisel_input = /home/wxm/cocoon/demo/alu-chisel/
+; result_dir = /home/wxm/cocoon/results/
+; clk_name = clk
+; delay = 1000
+
+; # Library settings
+; lib_name = gscl45nm
+; lef_input = /home/wxm/cocoon/demo/lib/gscl45nm.lef
+; liberty_input = /home/wxm/cocoon/demo/lib/gscl45nm.lib
+
+; # External toolkit settings
+; dreamplace_bin_path = /home/wxm/DREAMPlace/install/dreamplace/Placer.py
+; yosys_bin_path = /home/wxm/yosys/build
+
+; # Flow settings
+; flow = {'synth':'genus', 'placement':'innovus', 'routing':'innovus'}
+; n_iter_IFT = 0
+; verbose = False
+
+
diff --git a/engine.py b/engine.py
index 010455b..42fd883 100644
--- a/engine.py
+++ b/engine.py
@@ -63,6 +63,7 @@ def run(design, flow, flow_name):
 
         if x[0] == "InnovusPlace":
             tmp_op_pdn = place.InnovusPlace(design)
+            tmp_op_pdn.params['cadence_version'] = flow.cadence_version
             tmp_op_pdn.config(design, design_name + "_" + x[1])
             overall_tcl.write('source %s%s_to_place.tcl\n'%(tcl_path, design_name))
         
diff --git a/flow.py b/flow.py
index 77212a6..4bad948 100644
--- a/flow.py
+++ b/flow.py
@@ -13,6 +13,7 @@ class MyFlow(object):
         self.params_drc = []
         self.n_iter_IFT = 0
         self.verbose = True
+        self.cadence_version = '19'
         self.dreamplace_bin_path = " "
         self.yosys_bin_path = " "
 
diff --git a/ops/cds/drc.py b/ops/cds/drc.py
index a48c6e2..763fe37 100644
--- a/ops/cds/drc.py
+++ b/ops/cds/drc.py
@@ -18,7 +18,7 @@ class InnovusDRC():
     def config(self, design, tcl_file):
         tcl_path = util.getScriptPath(self.design)
         ret = 'check_design'
-        if self.params['out_file'] is not 'default':
+        if self.params['out_file'] != 'default':
             ret = ret + " -out_file " + self.params['out_file']
 
         if self.params['no_check']:
diff --git a/ops/cds/place.py b/ops/cds/place.py
index 07a727d..e594337 100644
--- a/ops/cds/place.py
+++ b/ops/cds/place.py
@@ -11,6 +11,7 @@ class InnovusPlace(object):
         self.params['concurrent_macros'] = False
         self.params['incremental'] = False
         self.params['noPrePlaceOpt'] = False
+        self.params['cadence_version'] = '19'
         
     def setParams(self, param):
         if self.params.get(param) == None:
@@ -21,6 +22,13 @@ class InnovusPlace(object):
     def config(self, design, tcl_file):
         tcl_path = util.getScriptPath(self.design)
         ret = 'place_design'
+        if self.params['cadence_version'] == '19':
+            ret = 'place_design'
+        elif self.params['cadence_version'] == '15':
+            ret = 'placeDesign'
+        else:
+            Exception("Invalid Cadence version!\n")
+            
         for i in self.params:
             if self.params[i] == True:
                 ret = ret + " -" + i