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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2016 Fabian J. Stumpf <sigrok@fabianstumpf.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/>.
##
import sigrokdecode as srd
class Decoder(srd.Decoder):
api_version = 2
id = 'dmx512'
name = 'DMX512'
longname = 'Digital MultipleX 512'
desc = 'Professional lighting control protocol.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['dmx512']
channels = (
{'id': 'dmx', 'name': 'DMX data', 'desc': 'Any DMX data line'},
)
annotations = (
('bit', 'Bit'),
('break', 'Break'),
('mab', 'Mark after break'),
('startbit', 'Start bit'),
('stopbits', 'Stop bit'),
('startcode', 'Start code'),
('channel', 'Channel'),
('interframe', 'Interframe'),
('interpacket', 'Interpacket'),
('data', 'Data'),
('error', 'Error'),
)
annotation_rows = (
('name', 'Logical', (1, 2, 5, 6, 7, 8)),
('data', 'Data', (9,)),
('bits', 'Bits', (0, 3, 4)),
('errors', 'Errors', (10,)),
)
def __init__(self):
self.samplerate = None
self.sample_usec = None
self.samplenum = -1
self.run_start = -1
self.run_bit = 0
self.state = 'FIND BREAK'
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value
self.sample_usec = 1 / value * 1000000
self.skip_per_bit = int(4 / self.sample_usec)
def putr(self, data):
self.put(self.run_start, self.samplenum, self.out_ann, data)
def decode(self, ss, es, data):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
for (self.samplenum, pins) in data:
# Seek for an interval with no state change with a length between
# 88 and 1000000 us (BREAK).
if self.state == 'FIND BREAK':
if self.run_bit == pins[0]:
continue
runlen = (self.samplenum - self.run_start) * self.sample_usec
if runlen > 88 and runlen < 1000000:
self.putr([1, ['Break']])
self.bit_break = self.run_bit
self.state = 'MARK MAB'
self.channel = 0
elif runlen >= 1000000:
# Error condition.
self.putr([10, ['Invalid break length']])
self.run_bit = pins[0]
self.run_start = self.samplenum
# Directly following the BREAK is the MARK AFTER BREAK.
elif self.state == 'MARK MAB':
if self.run_bit == pins[0]:
continue
self.putr([2, ['MAB']])
self.state = 'READ BYTE'
self.channel = 0
self.bit = 0
self.aggreg = pins[0]
self.run_start = self.samplenum
# Mark and read a single transmitted byte
# (start bit, 8 data bits, 2 stop bits).
elif self.state == 'READ BYTE':
self.next_sample = self.run_start + (self.bit + 1) * self.skip_per_bit
self.aggreg += pins[0]
if self.samplenum != self.next_sample:
continue
bit_value = 0 if round(self.aggreg/self.skip_per_bit) == self.bit_break else 1
if self.bit == 0:
self.byte = 0
self.putr([3, ['Start bit']])
if bit_value != 0:
# (Possibly) invalid start bit, mark but don't fail.
self.put(self.samplenum, self.samplenum,
self.out_ann, [10, ['Invalid start bit']])
elif self.bit >= 9:
self.put(self.samplenum - self.skip_per_bit,
self.samplenum, self.out_ann, [4, ['Stop bit']])
if bit_value != 1:
# Invalid stop bit, mark.
self.put(self.samplenum, self.samplenum,
self.out_ann, [10, ['Invalid stop bit']])
if self.bit == 10:
# On invalid 2nd stop bit, search for new break.
self.run_bit = pins[0]
self.state = 'FIND BREAK'
else:
# Label and process one bit.
self.put(self.samplenum - self.skip_per_bit,
self.samplenum, self.out_ann, [0, [str(bit_value)]])
self.byte |= bit_value << (self.bit - 1)
# Label a complete byte.
if self.bit == 10:
if self.channel == 0:
d = [5, ['Start code']]
else:
d = [6, ['Channel ' + str(self.channel)]]
self.put(self.run_start, self.next_sample, self.out_ann, d)
self.put(self.run_start + self.skip_per_bit,
self.next_sample - 2 * self.skip_per_bit,
self.out_ann, [9, [str(self.byte) + ' / ' + \
str(hex(self.byte))]])
# Continue by scanning the IFT.
self.channel += 1
self.run_start = self.samplenum
self.run_bit = pins[0]
self.state = 'MARK IFT'
self.aggreg = pins[0]
self.bit += 1
# Mark the INTERFRAME-TIME between bytes / INTERPACKET-TIME between packets.
elif self.state == 'MARK IFT':
if self.run_bit == pins[0]:
continue
if self.channel > 512:
self.putr([8, ['Interpacket']])
self.state = 'FIND BREAK'
self.run_bit = pins[0]
self.run_start = self.samplenum
else:
self.putr([7, ['Interframe']])
self.state = 'READ BYTE'
self.bit = 0
self.run_start = self.samplenum
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