add a Maxim DS2408 decoder

This is a 1-Wire 8-channel addressable switch.

2 files changed, 153 insertions, 0 deletions

diff --git a/decoders/ds2408/__init__.py b/decoders/ds2408/__init__.py
new file mode 100644
index 0000000..b196ce9
--- /dev/null
+++ b/decoders/ds2408/__init__.py
@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+This decoder stacks on top of the 'onewire_network' PD and decodes the
+Maxim DS2408 1-Wire 8-channel addressable switch protocol.
+'''
+
+from .pd import Decoder
diff --git a/decoders/ds2408/pd.py b/decoders/ds2408/pd.py
new file mode 100644
index 0000000..05fcbff
--- /dev/null
+++ b/decoders/ds2408/pd.py
@@ -0,0 +1,128 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2019 Mariusz Bialonczyk <manio@skyboo.net>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+# Dictionary of FUNCTION commands and their names.
+command = {
+    0xf0: 'Read PIO Registers',
+    0xf5: 'Channel Access Read',
+    0x5a: 'Channel Access Write',
+    0xcc: 'Write Conditional Search Register',
+    0xc3: 'Reset Activity Latches',
+    0x3c: 'Disable Test Mode',
+}
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'ds2408'
+    name = 'DS2408'
+    longname = 'Maxim DS2408'
+    desc = '1-Wire 8-channel addressable switch.'
+    license = 'gplv2+'
+    inputs = ['onewire_network']
+    outputs = ['ds2408']
+    annotations = (
+        ('text', 'Human-readable text'),
+    )
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        # Bytes for function command.
+        self.bytes = []
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putx(self, data):
+        self.put(self.ss, self.es, self.out_ann, data)
+
+    def decode(self, ss, es, data):
+        code, val = data
+
+        if code == 'RESET/PRESENCE':
+            self.ss, self.es = ss, es
+            self.putx([0, ['Reset/presence: %s'
+                           % ('true' if val else 'false')]])
+            self.bytes = []
+        elif code == 'ROM':
+            self.ss, self.es = ss, es
+            family_code = val & 0xff
+            self.putx([0, ['ROM: 0x%016x (family code 0x%02x)' % (val, family_code)]])
+            self.bytes = []
+        elif code == 'DATA':
+            self.bytes.append(val)
+            if 1 == len(self.bytes):
+                self.ss, self.es = ss, es
+                if val not in command:
+                    self.putx([0, ['Unrecognized command: 0x%02x' % val]])
+                else:
+                    self.putx([0, ['%s (0x%02x)' % (command[val], val)]])
+            elif 0xf0 == self.bytes[0]: # Read PIO Registers
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 3 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['Data: 0x%02x' % self.bytes[-1]]])
+            elif 0xf5 == self.bytes[0]: # Channel Access Read
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 2 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['PIO sample: 0x%02x' % self.bytes[-1]]])
+            elif 0x5a == self.bytes[0]: # Channel Access Write
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    if (self.bytes[-1] == (self.bytes[-2] ^ 0xff)):
+                      self.putx([0, ['Data: 0x%02x (bit-inversion correct: 0x%02x)' % (self.bytes[-2], self.bytes[-1])]])
+                    else:
+                      self.putx([0, ['Data error: second byte (0x%02x) is not bit-inverse of first (0x%02x)' % (self.bytes[-1], self.bytes[-2])]])
+                elif 3 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if 0xaa == self.bytes[-1]:
+                      self.putx([0, ['Success']])
+                    elif 0xff == self.bytes[-1]:
+                      self.putx([0, ['Fail New State']])
+            elif 0xcc == self.bytes[0]: # Write Conditional Search Register
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 3 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['Data: 0x%02x' % self.bytes[-1]]])
+            elif 0xc3 == self.bytes[0]: # Reset Activity Latches
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 2 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if 0xaa == self.bytes[-1]:
+                      self.putx([0, ['Success']])
+                    else:
+                      self.putx([0, ['Invalid byte']])