Rename 'ir_nec6122' PD to 'ir_nec', minor fixes and simplifications.

This IR protocol is commonly referred to as "the NEC protocol", and can be
generated by various means (not only via the NEC µPD6121/µPD6122 ICs).

Drop some unneeded variables and fix/simplify the code a bit.

2 files changed, 186 insertions, 0 deletions

diff --git a/decoders/ir_nec/__init__.py b/decoders/ir_nec/__init__.py
new file mode 100644
index 0000000..84bf428
--- /dev/null
+++ b/decoders/ir_nec/__init__.py
@@ -0,0 +1,26 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Gump Yang <gump.yang@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
+##
+
+'''
+NEC is a pulse-distance based infrared remote control protocol.
+'''
+
+from .pd import *
+
diff --git a/decoders/ir_nec/pd.py b/decoders/ir_nec/pd.py
new file mode 100644
index 0000000..542139d
--- /dev/null
+++ b/decoders/ir_nec/pd.py
@@ -0,0 +1,160 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Gump Yang <gump.yang@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
+##
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+    api_version = 1
+    id = 'ir_nec'
+    name = 'IR NEC'
+    longname = 'IR NEC'
+    desc = 'NEC infrared remote control protocol.'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = ['ir_nec']
+    probes = [
+        {'id': 'ir', 'name': 'IR', 'desc': 'Data line'},
+    ]
+    optional_probes = []
+    options = {
+        'cnt_lc': ['Leader code time (µs)', 13500],
+        'cnt_rc': ['Repeat code time (µs)', 11250],
+        'cnt_rc_end': ['Repeat code end time (µs)', 562],
+        'cnt_accuracy': ['Accuracy range (µs)', 100],
+        'cnt_dazero': ['Data 0 time (µs)', 1125],
+        'cnt_daone': ['Data 1 time (µs)', 2250],
+        'polarity': ['Polarity', 'active-low'],
+    }
+    annotations = [
+        ['bit', 'Bit'],
+        ['lc', 'Leader code'],
+        ['info', 'Info'],
+        ['error', 'Error'],
+    ]
+    annotation_rows = (
+        ('bits', 'Bits', (0,)),
+        ('fields', 'Fields', (1, 2, 3)),
+    )
+
+    def putx(self, data):
+        self.put(self.ss_start, self.samplenum, self.out_ann, data)
+
+    def putb(self, data):
+        self.put(self.ss_bit, self.samplenum, self.out_ann, data)
+
+    def __init__(self, **kwargs):
+        self.ss_bit = 0
+        self.state = 'IDLE'
+        self.data = 0
+        self.count = 0
+        self.ss_start = 0
+        self.act_polar = 0
+
+    def start(self):
+        # self.out_python = self.register(srd.OUTPUT_PYTHON)
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+        self.act_polar = 1 if self.options['polarity'] == 'active-low' else 0
+        self.old_ir = self.act_polar 
+
+    def metadata(self, key, value):
+        if key == srd.SRD_CONF_SAMPLERATE:
+            self.samplerate = value
+        samplerate = float(self.samplerate)
+
+        x = float(self.options['cnt_accuracy']) / 1000000.0
+        self.margin = int(samplerate * x) - 1
+        x = float(self.options['cnt_lc']) / 1000000.0
+        self.lc = int(samplerate * x) - 1
+        x = float(self.options['cnt_rc']) / 1000000.0
+        self.rc = int(samplerate * x) - 1
+        x = float(self.options['cnt_rc_end']) / 1000000.0
+        self.rc_end = int(samplerate * x) - 1
+        x = float(self.options['cnt_dazero']) / 1000000.0
+        self.dazero = int(samplerate * x) - 1
+        x = float(self.options['cnt_daone']) / 1000000.0
+        self.daone = int(samplerate * x) - 1
+        x = float(10000) / 1000000.0
+        self.end = int(samplerate * x) - 1
+
+    def handle_bits(self, tick):
+        ret = 0xff
+        if tick in range(self.dazero - self.margin, self.dazero + self.margin):
+            ret = 0
+        elif tick in range(self.daone - self.margin, self.daone + self.margin):
+            ret = 1
+
+        if ret < 2:
+            self.putb([0, ['%d' % ret]])
+            self.data = self.data * 2 + ret
+            self.count = self.count + 1
+
+        self.ss_bit = self.samplenum
+        return ret
+
+    def data_judge(self, name):
+        buf = int((self.data & 0xff00) / 0x100)
+        nbuf = int(self.data & 0xff)
+        ret = buf & nbuf
+        if ret == 0:
+            self.putx([2, ['%s: 0x%02x' % (name, buf)]])
+        else:
+            self.putx([3, ['%s Error: 0x%04x' % (name, self.data)]])
+
+        self.data = self.count = 0
+        self.ss_bit = self.ss_start = self.samplenum
+        return ret
+
+    def decode(self, ss, es, data):
+        if self.samplerate is None:
+            raise Exception("Cannot decode without samplerate.")
+        for (self.samplenum, pins) in data:
+            self.ir = pins[0]
+
+            # Wait for any edge (rising or falling).
+            if self.old_ir == self.ir:
+                continue
+
+            if self.old_ir == self.act_polar:
+                b = self.samplenum - self.ss_bit
+                # State machine.
+                if self.state == 'IDLE':
+                    if b in range(self.lc - self.margin, self.lc + self.margin):
+                        self.putx([1, ['Leader code', 'Leader', 'LC', 'L']])
+                        self.data = self.count = 0
+                        self.state = 'ADDRESS'
+                    elif b in range(self.rc - self.margin, self.rc + self.margin):
+                        self.putx([1, ['Repeat code', 'Repeat', 'RC', 'R']])
+                        self.data = self.count = 0
+                    self.ss_bit = self.ss_start = self.samplenum
+                elif self.state == 'ADDRESS':
+                    self.handle_bits(b)
+                    if self.count > 15:
+                        if self.data_judge(self.state) == 0:
+                            self.state = 'COMMAND'
+                        else:
+                            self.state = 'IDLE'
+                elif self.state == 'COMMAND':
+                    self.handle_bits(b)
+                    if self.count > 15:
+                        self.data_judge(self.state)
+                        self.state = 'IDLE'
+
+            self.old_ir = self.ir
+