Add decoder: signature analysis

2 files changed, 164 insertions, 0 deletions

diff --git a/decoders/signature/__init__.py b/decoders/signature/__init__.py
new file mode 100644
index 0000000..d37fd4a
--- /dev/null
+++ b/decoders/signature/__init__.py
@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2019 Shirow Miura <shirowmiura@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, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+Signature analysis function for troubleshooting logic circuits.
+This generates the same signature as Hewlett-Packard 5004A.
+'''
+
+from .pd import Decoder
diff --git a/decoders/signature/pd.py b/decoders/signature/pd.py
new file mode 100644
index 0000000..a86878f
--- /dev/null
+++ b/decoders/signature/pd.py
@@ -0,0 +1,139 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2019 Shirow Miura <shirowmiura@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, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+symbol_map = {
+    0b0000: '0',
+    0b1000: '1',
+    0b0100: '2',
+    0b1100: '3',
+    0b0010: '4',
+    0b1010: '5',
+    0b0110: '6',
+    0b1110: '7',
+    0b0001: '8',
+    0b1001: '9',
+    0b0101: 'A',
+    0b1101: 'C',
+    0b0011: 'F',
+    0b1011: 'H',
+    0b0111: 'P',
+    0b1111: 'U',
+}
+
+START, STOP, CLOCK, DATA = range(4)
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'signature'
+    name = 'Signature'
+    longname = 'Signature analysis'
+    desc = 'Annotate signature of logic patterns.'
+    license = 'gplv3+'
+    inputs = ['logic']
+    outputs = []
+    tags = ['Debug/trace', 'Util', 'Encoding']
+    channels = (
+        dict(id='start', name='START', desc='START channel'),
+        dict(id='stop', name='STOP', desc='STOP channel'),
+        dict(id='clk', name='CLOCK', desc='CLOCK channel'),
+        dict(id='data', name='DATA', desc='DATA channel')
+    )
+    options = (
+        dict(id='start_edge', desc='Edge-selection for START channel',
+             default='r', values=('r', 'f')),
+        dict(id='stop_edge', desc='Edge-selection for STOP channel',
+             default='r', values=('r', 'f')),
+        dict(id='clk_edge', desc='Edge-selection for CLOCK channel',
+             default='f', values=('r', 'f')),
+        dict(id='annbits', desc='Enable bit level annotation',
+             default='no', values=('yes', 'no'))
+    )
+    annotations = (
+        ('bit0', 'Bit0'),
+        ('bit1', 'Bit1'),
+        ('start', 'START'),
+        ('stop', 'STOP'),
+        ('sig', 'Sig')
+    )
+    annotation_rows = (
+        ('bits', 'Bits', (0, 1, 2, 3)),
+        ('sig', 'Sig', (4,))
+    )
+
+    def __init__(self):
+        pass
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putsig(self, ss, es, signature):
+        s = ''.join([symbol_map[(signature >>  0) & 0x0f],
+                     symbol_map[(signature >>  4) & 0x0f],
+                     symbol_map[(signature >>  8) & 0x0f],
+                     symbol_map[(signature >> 12) & 0x0f]])
+        self.put(ss, es, self.out_ann, [4, [s]])
+
+    def putb(self, ss, ann):
+        self.put(ss, self.samplenum, self.out_ann, ann)
+
+    def decode(self):
+        opt = self.options
+        start_edge_mode_rising = opt['start_edge'] == 'r'
+        stop_edge_mode_rising = opt['stop_edge'] == 'r'
+        annbits = opt['annbits'] == 'yes'
+        gate_is_open = False
+        sample_start = None
+        started = False
+        last_samplenum = 0
+        prev_start = 0 if start_edge_mode_rising else 1
+        prev_stop = 0 if stop_edge_mode_rising else 1
+        shiftreg = 0
+
+        while True:
+            start, stop, _, data = self.wait({CLOCK: opt['clk_edge']})
+            if start != prev_start and not gate_is_open:
+                gate_is_open = (start == 1) if start_edge_mode_rising else (start == 0)
+                if gate_is_open:
+                    # Start sampling.
+                    sample_start = self.samplenum
+                    started = True
+            elif stop != prev_stop and gate_is_open:
+                gate_is_open = not ((stop == 1) if stop_edge_mode_rising else (stop == 0))
+                if not gate_is_open:
+                    # Stop sampling.
+                    if annbits:
+                        self.putb(last_samplenum, [3, ['STOP', 'STP', 'P']])
+                    self.putsig(sample_start, self.samplenum, shiftreg)
+                    shiftreg = 0
+                    sample_start = None
+            if gate_is_open:
+                if annbits:
+                    if started:
+                        s = '<{}>'.format(data)
+                        self.putb(last_samplenum, [2, ['START' + s, 'STR' + s, 'S' + s]])
+                        started = False
+                    else:
+                        self.putb(last_samplenum, [data, [str(data)]])
+                incoming = (bin(shiftreg & 0b0000_0010_1001_0001).count('1') + data) & 1
+                shiftreg = (incoming << 15) | (shiftreg >> 1)
+            prev_start = start
+            prev_stop = stop
+            last_samplenum = self.samplenum