diff --git a/libsigrokdecode4DSL/decoders/autonegotiation/pd.py b/libsigrokdecode4DSL/decoders/autonegotiation/pd.py
index 748c12c7..bf0f5801 100755
--- a/libsigrokdecode4DSL/decoders/autonegotiation/pd.py
+++ b/libsigrokdecode4DSL/decoders/autonegotiation/pd.py
@@ -71,150 +71,171 @@ class Decoder(srd.Decoder):
         if key == srd.SRD_CONF_SAMPLERATE:
             self.samplerate = value
 
+    def changeState(self):
+        if self.pre_hex != self.hex:
+            if self.state == 'base page':
+                if ((self.hex>>14)&0x3) == 0x3:
+                    self.state = 'base page ack'
+            elif self.state == 'base page ack':
+                self.state = 'next page'
+            elif self.state == 'next page':
+                if ((self.hex>>14)&0x3) == 0x1:
+                    self.state = 'next page ack'
+            elif self.state == 'next page ack':
+                self.state = 'base page'
+
+    def decodeTiming(self):
+        self.wait({0: 'r'})
+        self.ss = self.samplenum
+        self.wait({0: 'e'})
+        self.es = self.samplenum
+
+        length = float(self.es - self.ss)/self.samplerate
+        if length <= 1.0e-5 and length >= 1.0e-6: # 1us ~ 10us 
+            self.put(self.ss, self.es, self.out_ann, [4, ['NLP']])
+            temp_length = self.ss - self.last_vaild_ss
+            length = float(temp_length)/self.samplerate
+            self.last_vaild_ss = self.ss
+            if length <= 7.0e-5 and length >= 6.0e-5: # 60us ~ 70us
+                self.hex = self.hex|0x1<<self.index
+                self.data_list.append({'start':self.ss, 
+                                    'end':self.es,
+                                    'Pre start':self.pre_ss, 
+                                    'Pre end':self.pre_es})
+                self.index = self.index + 1
+                self.last_vaild_ss = 0
+            elif length <= 1.4e-4 and length >= 1.2e-4: # 120us ~ 140us
+                self.data_list.append({'start':self.ss-(temp_length>>1),
+                                    'end':self.es-(temp_length>>1),
+                                    'Pre start':self.pre_ss,
+                                    'Pre end':self.pre_es})
+                self.index = self.index + 1
+            self.pre_ss = self.ss
+            self.pre_es = self.es
+
+    def decodeBasePage(self):
+        base_page_ta_dict = {
+            5:'10BaseT-HD',
+            6:'10BaseT-FD',
+            7:'100BaseTX-HD',
+            8:'100BaseTX-FD',
+            9:'100BaseT4',
+            10:'FC',
+            11:'AsyFC',
+            12:'Reserved',
+            13:'RF',
+            14:'ACK',
+            15:'NP',
+        }
+        if (self.hex&0x1f) == 0x1:
+            type_desc = '802.3'
+        elif (self.hex&0x1f) == 0x2:
+            type_desc = '802.9'
+        else:
+            type_desc = 'unknow'
+        for i in range(16):
+            self.put(self.data_list[i]['Pre start'],
+                        self.data_list[i]['end'], 
+                        self.out_ann, 
+                        [3, [str(hex(((self.hex>>i)&0x1)))]])
+            if i in base_page_ta_dict.keys():
+                self.put(self.data_list[i]['Pre start'],
+                            self.data_list[i]['end'], 
+                            self.out_ann, 
+                            [2, [base_page_ta_dict[i]]])
+        self.put(self.data_list[0]['Pre start'],
+                self.data_list[15]['end'],
+                self.out_ann,
+                [0, ["base page:"+str(hex(self.hex))]])
+        self.put(self.data_list[0]['Pre start'], 
+                self.data_list[4]['end'], 
+                self.out_ann, 
+                [1, ["Selector field:"+str(hex(self.hex&0x1f))]])
+        self.put(self.data_list[0]['Pre start'], 
+                self.data_list[4]['end'], 
+                self.out_ann, 
+                [2, [type_desc]])
+        self.put(self.data_list[5]['Pre start'],
+                self.data_list[12]['end'], 
+                self.out_ann, 
+                [1, ["Technology ability field:"+str(hex(((self.hex>>5)&0xff)))]])
+        self.put(self.data_list[13]['Pre start'],
+                self.data_list[15]['end'], 
+                self.out_ann, 
+                [1, ["Other fields:"+str(hex(((self.hex>>13)&0x7)))]])
+
+    def decodeNextPage(self):
+        next_page_ta_dict = {
+            0:'1000BaseT M/S CFG EN',
+            1:'1000BaseT M/S CFG Vale',
+            2:'Port type',
+            3:'1000BaseT-FD',
+            4:'1000BaseT-HD',
+            5:'10GBaseT-FD',
+            6:'10GBaseT M/S CFG EN',
+            7:'10GBaseT M/S CFG Vale',
+            8:'Reserved',
+            9:'Reserved',
+            10:'Reserved',
+        }
+        next_page_ot_dict = {
+            11:'T',
+            12:'ACK2',
+            13:'MP',
+            14:'ACK',
+            15:'NP',
+        }
+        if ((self.hex>>13)&0x1) == 0x1:
+            mp = "Technology ability field:"
+        else :
+            mp = "Unformatted code field:"
+        for i in range(16):
+            self.put(self.data_list[i]['Pre start'],
+                    self.data_list[i]['end'], 
+                    self.out_ann, 
+                    [3, [str(hex(((self.hex>>i)&0x1)))]])
+            if i in next_page_ot_dict.keys():
+                self.put(self.data_list[i]['Pre start'],
+                        self.data_list[i]['end'], 
+                        self.out_ann, 
+                        [2, [next_page_ot_dict[i]]])
+            if mp == "Technology ability field:":
+                if i in next_page_ta_dict.keys():
+                    self.put(self.data_list[i]['Pre start'],
+                            self.data_list[i]['end'], 
+                            self.out_ann, 
+                            [2, [next_page_ta_dict[i]]])
+        self.put(self.data_list[0]['Pre start'],
+                    self.data_list[15]['end'],
+                    self.out_ann,
+                    [0, ["next page:"+str(hex(self.hex))]])
+        self.put(self.data_list[0]['Pre start'], 
+                self.data_list[10]['end'], 
+                self.out_ann, 
+                [1, [mp+str(hex((self.hex&0x7ff)))]])
+        if mp == "Unformatted code field:":
+            self.put(self.data_list[0]['Pre start'], 
+                        self.data_list[10]['end'], 
+                        self.out_ann,
+                        [2, ["Master-Slave seed value (MSB)"]])
+        self.put(self.data_list[11]['Pre start'],
+                self.data_list[15]['end'], 
+                self.out_ann, 
+                [1, ["Other fields:"+str(hex(((self.hex>>11)&0x1f)))]])
+
+    def updateOnceDecode(self):
+        self.pre_hex = self.hex
+        self.data_list = []
+        self.index = 0
+        self.hex = 0
+
     def decode(self):
         while True:
-            self.wait({0: 'r'})
-            self.ss = self.samplenum
-            self.wait({0: 'e'})
-            self.es = self.samplenum
-
-            length = float(self.es - self.ss)/self.samplerate
-            if length <= 1.0e-5 and length >= 1.0e-6: # 1us ~ 10us 
-                self.put(self.ss, self.es, self.out_ann, [4, ['NLP']])
-                temp_length = self.ss - self.last_vaild_ss
-                length = float(temp_length)/self.samplerate
-                self.last_vaild_ss = self.ss
-                if length <= 7.0e-5 and length >= 6.0e-5: # 60us ~ 70us
-                    self.hex = self.hex|0x1<<self.index
-                    self.data_list.append({'start':self.ss, 
-                                      'end':self.es,
-                                      'Pre start':self.pre_ss, 
-                                      'Pre end':self.pre_es})
-                    self.index = self.index + 1
-                    self.last_vaild_ss = 0
-                elif length <= 1.4e-4 and length >= 1.2e-4: # 120us ~ 140us
-                    self.data_list.append({'start':self.ss-(temp_length>>1),
-                                      'end':self.es-(temp_length>>1),
-                                      'Pre start':self.pre_ss,
-                                      'Pre end':self.pre_es})
-                    self.index = self.index + 1
-                self.pre_ss = self.ss
-                self.pre_es = self.es
-
+            self.decodeTiming()
             if self.index == 16:
-                if self.pre_hex != self.hex:
-                    if self.state == 'base page':
-                        if ((self.hex>>14)&0x3) == 0x3:
-                            self.state = 'base page ack'
-                    elif self.state == 'base page ack':
-                        self.state = 'next page'
-                    elif self.state == 'next page':
-                        if ((self.hex>>14)&0x3) == 0x1:
-                            self.state = 'next page ack'
-                    elif self.state == 'next page ack':
-                        self.state = 'base page'
+                self.changeState()
                 if self.state == 'base page' or self.state == 'base page ack':
-                    base_page_ta_dict = {
-                        5:'10BaseT-HD',
-                        6:'10BaseT-FD',
-                        7:'100BaseTX-HD',
-                        8:'100BaseTX-FD',
-                        9:'100BaseT4',
-                        10:'FC',
-                        11:'AsyFC',
-                        12:'Reserved',
-                        13:'RF',
-                        14:'ACK',
-                        15:'NP',
-                    }
-                    if (self.hex&0x1f) == 0x1:
-                        type_desc = '802.3'
-                    elif (self.hex&0x1f) == 0x2:
-                        type_desc = '802.9'
-                    else:
-                        type_desc = 'unknow'
-                    for i in range(16):
-                        self.put(self.data_list[i]['Pre start'],
-                                 self.data_list[i]['end'], 
-                                 self.out_ann, 
-                                 [3, [str(hex(((self.hex>>i)&0x1)))]])
-                        if i in base_page_ta_dict.keys():
-                            self.put(self.data_list[i]['Pre start'],
-                                     self.data_list[i]['end'], 
-                                     self.out_ann, 
-                                     [2, [base_page_ta_dict[i]]])
-                    self.put(self.data_list[0]['Pre start'],
-                            self.data_list[15]['end'],
-                            self.out_ann,
-                            [0, ["base page:"+str(hex(self.hex))]])
-                    self.put(self.data_list[0]['Pre start'], 
-                            self.data_list[4]['end'], 
-                            self.out_ann, 
-                            [1, ["Selector field:"+str(hex(self.hex&0x1f))]])
-                    self.put(self.data_list[0]['Pre start'], 
-                            self.data_list[4]['end'], 
-                            self.out_ann, 
-                            [2, [type_desc]])
-                    self.put(self.data_list[5]['Pre start'],
-                            self.data_list[12]['end'], 
-                            self.out_ann, 
-                            [1, ["Technology ability field:"+str(hex(((self.hex>>5)&0xff)))]])
-                    self.put(self.data_list[13]['Pre start'],
-                            self.data_list[15]['end'], 
-                            self.out_ann, 
-                            [1, ["Other fields:"+str(hex(((self.hex>>13)&0x7)))]])
+                    self.decodeBasePage()
                 elif self.state == 'next page' or self.state == 'next page ack':
-                    next_page_ta_dict = {
-                        0:'1000BaseT M/S CFG EN',
-                        1:'1000BaseT M/S CFG Vale',
-                        2:'Port type',
-                        3:'1000BaseT-FD',
-                        4:'1000BaseT-HD',
-                        5:'10GBaseT-FD',
-                        6:'10GBaseT M/S CFG EN',
-                        7:'10GBaseT M/S CFG Vale',
-                        8:'Reserved',
-                        9:'Reserved',
-                        10:'Reserved',
-                        11:'T',
-                        12:'ACK2',
-                        13:'MP',
-                        14:'ACK',
-                        15:'NP',
-                    }
-                    if ((self.hex>>13)&0x1) == 0x1:
-                        mp = "Technology ability field:"
-                    else :
-                        mp = "Unformatted code field:"
-                    for i in range(16):
-                        self.put(self.data_list[i]['Pre start'],
-                                self.data_list[i]['end'], 
-                                self.out_ann, 
-                                [3, [str(hex(((self.hex>>i)&0x1)))]])
-                        if i in [11,12,13,14,15] or mp == "Technology ability field:":
-                            if i in next_page_ta_dict.keys():
-                                self.put(self.data_list[i]['Pre start'],
-                                        self.data_list[i]['end'], 
-                                        self.out_ann, 
-                                        [2, [next_page_ta_dict[i]]])
-                    self.put(self.data_list[0]['Pre start'],
-                             self.data_list[15]['end'],
-                             self.out_ann,
-                             [0, ["next page:"+str(hex(self.hex))]])
-                    self.put(self.data_list[0]['Pre start'], 
-                            self.data_list[10]['end'], 
-                            self.out_ann, 
-                            [1, [mp+str(hex((self.hex&0x7ff)))]])
-                    if mp == "Unformatted code field:":
-                        self.put(self.data_list[0]['Pre start'], 
-                                 self.data_list[10]['end'], 
-                                 self.out_ann,
-                                 [2, ["Master-Slave seed value (MSB)"]])
-                    self.put(self.data_list[11]['Pre start'],
-                            self.data_list[15]['end'], 
-                            self.out_ann, 
-                            [1, ["Other fields:"+str(hex(((self.hex>>11)&0x1f)))]])
-                self.pre_hex = self.hex
-                self.data_list = []
-                self.index = 0
-                self.hex = 0
\ No newline at end of file
+                    self.decodeNextPage()
+                self.updateOnceDecode()