onewire: added transport layer decoder, it does not do much for now

3 files changed, 186 insertions, 0 deletions

diff --git a/decoders/onewire_transport/Makefile.am b/decoders/onewire_transport/Makefile.am
new file mode 100644
index 0000000..982525d
--- /dev/null
+++ b/decoders/onewire_transport/Makefile.am
@@ -0,0 +1,26 @@
+##
+## This file is part of the sigrok 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+pkgdatadir = $(DECODERS_DIR)/onewire_transport
+
+dist_pkgdata_DATA = __init__.py onewire_transport.py
+
+CLEANFILES = *.pyc
+
diff --git a/decoders/onewire_transport/__init__.py b/decoders/onewire_transport/__init__.py
new file mode 100644
index 0000000..28db017
--- /dev/null
+++ b/decoders/onewire_transport/__init__.py
@@ -0,0 +1,76 @@
+##
+## This file is part of the sigrok 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+'''
+1-Wire protocol decoder.
+
+The 1-Wire protocol enables bidirectional communication over a single wire (and
+ground) between a single master and one or multiple slaves. The protocol is
+layered, the provided parser decodes the next layers:
+- Link layer (reset, presence detection, reading/writing bits)
+- Network layer (skip, search, match device ROM addresses)
+The higher layers (transport, presentation) are not decoded, since they are
+mostly device specific and it would take a lot of code to interpret them.
+
+Sample rate:
+A high enough sample rate is required to properly detect all the elements of
+the protocol. A lower sample rate can be used if the master does not use
+overdrive communication speed. The next minimal values should be used:
+- overdrive     available:   2MHz minimum, 5MHz suggested
+- overdrive not available: 400kHz minimum, 1MHz suggested
+
+Probes:
+1-Wire requires a single signal, but some master implementations might have a
+separate signal use to deliver power to the bus during temperature conversion
+as an example. This power signal is currently not parsed.
+- owr (1-Wire bus)
+- pwr (1-Wire power)
+
+Options:
+1-Wire is an asynchronous protocol, so the decoder must know the sample rate.
+The timing for sampling bits, presence and reset is calculated by the decoder,
+but in case the user wishes to use different values, it is possible to
+configure the next timing values (number of sample rate periods):
+- overdrive              (if active the decoder will be prepared for overdrive)
+- cnt_normal_bit         (time for normal mode sample bit)
+- cnt_normal_presence    (time for normal mode sample presence)
+- cnt_normal_reset       (time for normal mode reset)
+- cnt_overdrive_bit      (time for overdrive mode sample bit)
+- cnt_overdrive_presence (time for overdrive mode sample presence)
+- cnt_overdrive_reset    (time for overdrive mode reset)
+This options should be configured only on very rare cases and the user should
+read the decoder source code to understand them correctly.
+
+Annotations:
+Annotations can be shown for each layer of the protocol separately:
+- link (the value of each transmitted bit is shown separately)
+- network (the ROM command, and address are shown)
+- transport (only transport layer byte transfers are shown)
+If link layer annotations are shown, possible issues with sample rate and sample
+timing are also shown.
+
+TODO:
+- add CRC checks for network layer
+- add transport layer code
+- review link layer code, to check for protocol correctness
+- define output protocol
+'''
+
+from .onewire_transport import *
diff --git a/decoders/onewire_transport/onewire_transport.py b/decoders/onewire_transport/onewire_transport.py
new file mode 100644
index 0000000..bc9efbb
--- /dev/null
+++ b/decoders/onewire_transport/onewire_transport.py
@@ -0,0 +1,84 @@
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com>
+##
+## 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, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+# 1-Wire protocol decoder
+
+import sigrokdecode as srd
+
+command = {0x44: "TEMPERATURE CONVERSION",
+           0xbe: "READ SCRATCHPAD"}
+
+class Decoder(srd.Decoder):
+    api_version = 1
+    id = 'onewire_transport'
+    name = '1-Wire transport layer'
+    longname = '1-Wire serial communication bus'
+    desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
+    license = 'gplv2+'
+    inputs = ['onewire_network']
+    outputs = []
+    probes = []
+    optional_probes = []
+    options = {}
+    annotations = [
+        ['Transport', 'Transport layer events'],
+    ]
+
+    def __init__(self, **kwargs):
+        # Event timing variables
+        self.trn_beg = 0
+        self.trn_end = 0
+        # Transport layer variables
+        self.state   = 'ROM'
+        self.rom     = 0x0000000000000000
+
+    def start(self, metadata):
+        self.out_ann   = self.add(srd.OUTPUT_ANN  , 'onewire_transport')
+
+    def report(self):
+        pass
+
+    def decode(self, ss, es, data):
+        [code, val] = data
+
+        # State machine.
+        if (code == "RESET/PRESENCE"):
+            self.put(ss, es, self.out_ann, [0, ['RESET/PRESENCE: %s' % ('True' if val else 'False')]])
+            self.state = "ROM"
+        elif (code == "ROM"):
+            self.rom = val
+            self.put(ss, es, self.out_ann, [0, ['ROM: 0x%016x' % (val)]])
+            self.state = "COMMAND"
+        elif (code == "DATA"):
+            if (self.state == "COMMAND"):
+                    if (val in command):
+                        self.put(ss, es, self.out_ann, [0, ['FUNCTION COMMAND: 0x%02x \'%s\'' % (val, command[val])]])
+                        self.state = command[val]
+                    else:
+                        self.put(ss, es, self.out_ann, [0, ['FUNCTION COMMAND: 0x%02x \'%s\'' % (val, 'UNRECOGNIZED')]])
+                        self.state = "UNRECOGNIZED"
+            elif (self.state == "READ SCRATCHPAD"):
+                self.put(ss, es, self.out_ann, [0, ['SCRATCHPAD DATA: 0x%02x' % (val)]])
+            elif (self.state == "TEMPERATURE CONVERSION"):
+                self.put(ss, es, self.out_ann, [0, ['TEMPERATURE CONVERSION STATUS: 0x%02x' % (val)]])
+            elif (self.state == "UNRECOGNIZED"):
+                self.put(ss, es, self.out_ann, [0, ['UNRECOGNIZED: 0x%02x' % (val)]])
+            else:
+                raise Exception('Invalid state: %s' % self.state)