add decoder for the SCS bus (Sistema Cablaggio Semplificato)

decoders/scs/__init__.py

@@ -0,0 +1,26 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2020 Michael Stapelberg
+##
+## 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/>.
+##
+
+'''
+Decoder for the SCS bus (Sistema Cablaggio Semplificato, i.e. Simplified Cable
+Solution), a fieldbus network protocol for home automation, used by bTicino and
+Legrand.
+'''
+
+from .pd import Decoder

decoders/scs/pd.py

@@ -0,0 +1,135 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2020 Michael Stapelberg
+##
+## 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
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'scs'
+    name = 'SCS'
+    longname = 'Sistema Cablaggio Semplificato (Simplified Cable Solution)'
+    desc = 'fieldbus network protocol for home automation, used by bTicino and Legrand'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = []
+    tags = ['IC', 'IR']
+    channels = (
+        {'id': 'data', 'name': 'Data', 'desc': 'Data line'},
+    )
+    annotations = (
+        ('startbit', 'start bit'),
+        ('data', 'data bit'),
+        ('stopbit', 'stop bit'),
+        ('val', 'value'),
+        ('telegram', 'telegram'),
+        ('scs', 'scs'),
+    )
+    annotation_rows = (
+        ('encoding', 'Encoding', (0, 2)),
+        ('data', 'Data', (1,)),
+        ('val', 'Value', (3,)),
+        ('telegram', 'Telegram', (4,)),
+        ('scs', 'SCS', (5,)),
+    )
+    options = ()
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.samplenumber_last = None
+        self.pulses = []
+        self.bits = []
+        self.labels = []
+        self.bit_count = 0
+        self.ss = None
+        self.es = None
+        self.state = 'IDLE'
+        self.telegram = []
+        self.telegram_idx = []
+
+    # called before beginning of decoding
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    # called to start decoding
+    def decode(self):
+        while True:
+            if len(self.telegram) == 7:
+                self.put(self.telegram_idx[0][0], self.telegram_idx[6][1], self.out_ann, [4, ['7-byte SCS telegram']])
+                self.annotate_telegram(0, [5, ['init']])
+                self.annotate_telegram(1, [5, ['addr']])
+                self.annotate_telegram(2, [5, ['??']])
+                self.annotate_telegram(3, [5, ['request']])
+                self.annotate_telegram(4, [5, ['??']])
+                wantcrc = self.telegram[1] ^ self.telegram[2] ^ self.telegram[3] ^ self.telegram[4]
+                crc = 'good' if wantcrc == self.telegram[5] else 'bad'
+                self.annotate_telegram(5, [5, ['%s crc' % crc]])
+                self.annotate_telegram(6, [5, ['term']])
+                self.telegram = []
+                self.telegram_idx = []
+            # Wait for the start of a transmission:
+            # the SCS start bit is always 0, i.e. 34us low, 70us high
+            pin = self.wait({0: 'l'})
+            start = self.samplenum
+            self.discard_rest()
+            end = self.samplenum
+
+            self.put(start, end, self.out_ann, [0, ['start = %s' % pin]])
+
+            startbitsample = self.samplenum
+            val = 0
+            for i in range(0, 8):
+                bit = self.demodulate_databit()
+                val = val | (int(bit[0]) << i)
+            self.telegram = self.telegram + [val]
+            self.telegram_idx = self.telegram_idx + [[startbitsample, self.samplenum]]
+            self.put(startbitsample, self.samplenum, self.out_ann, [3, ['0x%x' % val]])
+
+            # stop bit should be 1!
+            self.expect_stop()
+
+    # helper functions (not part of the decoder API) below:
+
+    def discard_rest(self):
+        # skip the remaining 16 samples (17 samples = 34us)
+        self.wait({'skip': 16})
+        # skip the remaining 35 samples (35 samples = 70us)
+        # (skipping one extra sample to avoid going out of sync)
+        self.wait({'skip': 36})
+
+    def demodulate_databit(self):
+        pin = self.wait()
+        start = self.samplenum
+        self.discard_rest()
+        end = self.samplenum
+        self.put(start, end, self.out_ann, [1, ['%s' % pin]])
+        return pin
+
+    def expect_stop(self):
+        pin = self.wait()
+        start = self.samplenum
+        self.discard_rest()
+        end = self.samplenum
+        self.put(start, end, self.out_ann, [2, ['stop = %s' % pin]])
+
+    def annotate_telegram(self, idx, data):
+        start = self.telegram_idx[idx][0]
+        end = self.telegram_idx[idx][1]
+        self.put(start, end, self.out_ann, data)