decoders/ds243x/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
   5 ## Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
   6 ##
   7 ## This program is free software; you can redistribute it and/or modify
   8 ## it under the terms of the GNU General Public License as published by
   9 ## the Free Software Foundation; either version 2 of the License, or
  10 ## (at your option) any later version.
  11 ##
  12 ## This program is distributed in the hope that it will be useful,
  13 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 ## GNU General Public License for more details.
  16 ##
  17 ## You should have received a copy of the GNU General Public License
  18 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
  19 ##
  20
  21 import sigrokdecode as srd
  22
  23 # Dictionary of FUNCTION commands and their names.
  24 commands_2432 = {
  25     0x0f: 'Write scratchpad',
  26     0xaa: 'Read scratchpad',
  27     0x55: 'Copy scratchpad',
  28     0xf0: 'Read memory',
  29     0x5a: 'Load first secret',
  30     0x33: 'Compute next secret',
  31     0xa5: 'Read authenticated page',
  32 }
  33
  34 commands_2433 = {
  35     0x0f: 'Write scratchpad',
  36     0xaa: 'Read scratchpad',
  37     0x55: 'Copy scratchpad',
  38     0xf0: 'Read memory',
  39 }
  40
  41 # Maxim DS243x family code, present at the end of the ROM code.
  42 family_codes = {
  43     0x33: ('DS2432', commands_2432),
  44     0x23: ('DS2433', commands_2433),
  45 }
  46
  47 # Calculate the CRC-16 checksum.
  48 # Initial value: 0x0000, xor-in: 0x0000, polynom 0x8005, xor-out: 0xffff.
  49 def crc16(byte_array):
  50     reverse = 0xa001 # Use the reverse polynom to make algo simpler.
  51     crc = 0x0000 # Initial value.
  52     # Reverse CRC calculation.
  53     for byte in byte_array:
  54         for bit in range(8):
  55             if (byte ^ crc) & 1:
  56                 crc = (crc >> 1) ^ reverse
  57             else:
  58                 crc >>= 1
  59             byte >>= 1
  60     crc ^= 0xffff # Invert CRC.
  61     return crc
  62
  63 class Decoder(srd.Decoder):
  64     api_version = 3
  65     id = 'ds243x'
  66     name = 'DS243x'
  67     longname = 'Maxim DS2432/2433'
  68     desc = 'Maxim DS243x series 1-Wire EEPROM protocol.'
  69     license = 'gplv2+'
  70     inputs = ['onewire_network']
  71     outputs = ['ds243x']
  72     annotations = (
  73         ('text', 'Human-readable text'),
  74     )
  75
  76     def __init__(self):
  77         # Bytes for function command.
  78         self.bytes = []
  79         self.family_code = None
  80         self.family = ''
  81         self.commands = commands_2432 # Use max command set until we know better.
  82
  83     def start(self):
  84         self.out_ann = self.register(srd.OUTPUT_ANN)
  85
  86     def putx(self, data):
  87         self.put(self.ss, self.es, self.out_ann, data)
  88
  89     def decode(self, ss, es, data):
  90         code, val = data
  91
  92         if code == 'RESET/PRESENCE':
  93             self.ss, self.es = ss, es
  94             self.putx([0, ['Reset/presence: %s'
  95                            % ('true' if val else 'false')]])
  96             self.bytes = []
  97         elif code == 'ROM':
  98             self.ss, self.es = ss, es
  99             self.family_code = val & 0xff
 100
 101             s = None
 102             if self.family_code in family_codes:
 103                 self.family, self.commands = family_codes[val & 0xff]
 104                 s = 'is 0x%02x, %s detected' % (self.family_code, self.family)
 105             else:
 106                 s = '%x%02x unknown' % (self.family_code)
 107
 108             self.putx([0, ['ROM: 0x%016x (%s)' % (val, 'family code ' + s),
 109                            'ROM: 0x%016x (%s)' % (val, self.family)]])
 110             self.bytes = []
 111         elif code == 'DATA':
 112             self.bytes.append(val)
 113             if 1 == len(self.bytes):
 114                 self.ss, self.es = ss, es
 115                 if val not in self.commands:
 116                     self.putx([0, ['Unrecognized command: 0x%02x' % val]])
 117                 else:
 118                     self.putx([0, ['Function command: %s (0x%02x)'
 119                                    % (self.commands[val], val)]])
 120             elif 0x0f == self.bytes[0]: # Write scratchpad
 121                 if 2 == len(self.bytes):
 122                     self.ss = ss
 123                 elif 3 == len(self.bytes):
 124                     self.es = es
 125                     self.putx([0, ['Target address: 0x%04x'
 126                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 127                 elif 4 == len(self.bytes):
 128                     self.ss = ss
 129                 elif 11 == len(self.bytes):
 130                     self.es = es
 131                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 132                                        for n in self.bytes[3:11]))]])
 133                 elif 12 == len(self.bytes):
 134                     self.ss = ss
 135                 elif 13 == len(self.bytes):
 136                     self.es = es
 137                     self.putx([0, ['CRC: '
 138                         + ('ok' if crc16(self.bytes[0:11]) == (self.bytes[11]
 139                         + (self.bytes[12] << 8)) else 'error')]])
 140             elif 0xaa == self.bytes[0]: # Read scratchpad
 141                 if 2 == len(self.bytes):
 142                     self.ss = ss
 143                 elif 3 == len(self.bytes):
 144                     self.es = es
 145                     self.putx([0, ['Target address: 0x%04x'
 146                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 147                 elif 4 == len(self.bytes):
 148                     self.ss, self.es = ss, es
 149                     self.putx([0, ['Data status (E/S): 0x%02x'
 150                                    % (self.bytes[3])]])
 151                 elif 5 == len(self.bytes):
 152                     self.ss = ss
 153                 elif 12 == len(self.bytes):
 154                     self.es = es
 155                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 156                                        for n in self.bytes[4:12]))]])
 157                 elif 13 == len(self.bytes):
 158                     self.ss = ss
 159                 elif 14 == len(self.bytes):
 160                     self.es = es
 161                     self.putx([0, ['CRC: '
 162                         + ('ok' if crc16(self.bytes[0:12]) == (self.bytes[12]
 163                         + (self.bytes[13] << 8)) else 'error')]])
 164             elif 0x5a == self.bytes[0]: # Load first secret
 165                 if 2 == len(self.bytes):
 166                     self.ss = ss
 167                 elif 4 == len(self.bytes):
 168                     self.es = es
 169                     self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
 170                         + (','.join(format(n, '#04x')
 171                             for n in self.bytes[1:4]))]])
 172                 elif 4 < len(self.bytes):
 173                     self.ss, self.es = ss, es
 174                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 175                         self.putx([0, ['End of operation']])
 176             elif 0x33 == self.bytes[0]: # Compute next secret
 177                 if 2 == len(self.bytes):
 178                     self.ss = ss
 179                 elif 3 == len(self.bytes):
 180                     self.es = es
 181                     self.putx([0, ['Target address: 0x%04x'
 182                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 183                 elif 3 < len(self.bytes):
 184                     self.ss, self.es = ss, es
 185                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 186                         self.putx([0, ['End of operation']])
 187             elif 0x55 == self.bytes[0]: # Copy scratchpad
 188                 if 2 == len(self.bytes):
 189                     self.ss = ss
 190                 elif 4 == len(self.bytes):
 191                     self.es = es
 192                     self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
 193                         + (','.join(format(n, '#04x')
 194                             for n in self.bytes[1:4]))]])
 195                 elif 5 == len(self.bytes):
 196                     self.ss = ss
 197                 elif 24 == len(self.bytes):
 198                     self.es = es
 199                     mac = ','.join(format(n, '#04x') for n in self.bytes[4:24])
 200                     self.putx([0, ['Message authentication code: ' + mac,
 201                                    'MAC: ' + mac]])
 202                 elif 24 < len(self.bytes):
 203                     self.ss, self.es = ss, es
 204                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 205                         self.putx([0, ['Operation succeeded']])
 206                     elif (0 == self.bytes[-1]):
 207                         self.putx([0, ['Operation failed']])
 208             elif 0xa5 == self.bytes[0]: # Read authenticated page
 209                 if 2 == len(self.bytes):
 210                     self.ss = ss
 211                 elif 3 == len(self.bytes):
 212                     self.es = es
 213                     self.putx([0, ['Target address: 0x%04x'
 214                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 215                 elif 4 == len(self.bytes):
 216                     self.ss = ss
 217                 elif 35 == len(self.bytes):
 218                     self.es = es
 219                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 220                                        for n in self.bytes[3:35]))]])
 221                 elif 36 == len(self.bytes):
 222                     self.ss, self.es = ss, es
 223                     self.putx([0, ['Padding: '
 224                         + ('ok' if 0xff == self.bytes[-1] else 'error')]])
 225                 elif 37 == len(self.bytes):
 226                     self.ss = ss
 227                 elif 38 == len(self.bytes):
 228                     self.es = es
 229                     self.putx([0, ['CRC: '
 230                         + ('ok' if crc16(self.bytes[0:36]) == (self.bytes[36]
 231                         + (self.bytes[37] << 8)) else 'error')]])
 232                 elif 39 == len(self.bytes):
 233                     self.ss = ss
 234                 elif 58 == len(self.bytes):
 235                     self.es = es
 236                     mac = ','.join(format(n, '#04x') for n in self.bytes[38:58])
 237                     self.putx([0, ['Message authentication code: ' + mac,
 238                                    'MAC: ' + mac]])
 239                 elif 59 == len(self.bytes):
 240                     self.ss = ss
 241                 elif 60 == len(self.bytes):
 242                     self.es = es
 243                     self.putx([0, ['MAC CRC: '
 244                         + ('ok' if crc16(self.bytes[38:58]) == (self.bytes[58]
 245                         + (self.bytes[59] << 8)) else 'error')]])
 246                 elif 60 < len(self.bytes):
 247                     self.ss, self.es = ss, es
 248                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 249                         self.putx([0, ['Operation completed']])
 250             elif 0xf0 == self.bytes[0]: # Read memory
 251                 if 2 == len(self.bytes):
 252                     self.ss = ss
 253                 elif 3 == len(self.bytes):
 254                     self.es = es
 255                     self.putx([0, ['Target address: 0x%04x'
 256                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 257                 elif 3 < len(self.bytes):
 258                     self.ss, self.es = ss, es
 259                     self.putx([0, ['Data: 0x%02x' % (self.bytes[-1])]])