diff options
| -rw-r--r-- | decoders/ltc242x/__init__.py | 25 | ||||
| -rw-r--r-- | decoders/ltc242x/pd.py | 95 |
2 files changed, 120 insertions, 0 deletions
diff --git a/decoders/ltc242x/__init__.py b/decoders/ltc242x/__init__.py new file mode 100644 index 0000000..43d9d34 --- /dev/null +++ b/decoders/ltc242x/__init__.py @@ -0,0 +1,25 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2020 Analog Devices Inc. +## +## 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 3 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/>. +## + +''' +This decoder stacks on top of the 'spi' PD and decodes the +Linear Technology LTC2421/LTC2422 protocol. +''' + +from .pd import Decoder diff --git a/decoders/ltc242x/pd.py b/decoders/ltc242x/pd.py new file mode 100644 index 0000000..0086381 --- /dev/null +++ b/decoders/ltc242x/pd.py @@ -0,0 +1,95 @@ +## +## This file is part of the libsigrokdecode project. +## +## Copyright (C) 2020 Analog Devices Inc. +## +## 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 3 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 + +channel_format = ['Channel %d', 'Ch %d', '%d'] +input_voltage_format = ['%fV', '%fV', '%.6fV', '%.2fV'] + +class Decoder(srd.Decoder): + api_version = 3 + id = 'ltc242x' + name = 'LTC242x' + longname = 'Linear Technology LTC242x' + desc = 'Linear Technology LTC2421/LTC2422 1-/2-channel 20-bit ADC.' + license = 'gplv2+' + inputs = ['spi'] + outputs = [] + tags = ['Display'] + annotations = ( + ('channel', 'Channel'), + ('input', 'Input voltage'), + ) + annotation_rows = ( + ('channel', 'Channel', (0,)), + ('input', 'Input voltage', (1,)), + ) + options = ( + {'id': 'ref', 'desc': 'Reference voltage', 'default': 1.5}, + ) + + def __init__(self): + self.reset() + + def reset(self): + self.data = 0 + self.ss, self.es = 0, 0 + + def start(self): + self.out_ann = self.register(srd.OUTPUT_ANN) + + def handle_channel(self, data): + channel = (data & (1 << 22)) >> 22 + ann = [] + for format in channel_format: + ann.append(format % channel) + + self.put(self.ss, self.es, self.out_ann, [0, ann]) + + def handle_input_voltage(self, data): + input_voltage = data & 0x3FFFFF + input_voltage = -(2**21 - input_voltage) + input_voltage = (input_voltage / 0xfffff) * self.options['ref'] + ann = [] + for format in input_voltage_format: + ann.append(format % input_voltage) + + self.put(self.ss, self.es, self.out_ann, [1, ann]) + + def decode(self, ss, es, data): + ptype = data[0] + + if ptype == 'CS-CHANGE': + cs_old, cs_new = data[1:] + if cs_old is not None and cs_old == 0 and cs_new == 1: + self.es = es + self.data >>= 1 + self.handle_channel(self.data) + self.handle_input_voltage(self.data) + + self.data = 0 + elif cs_old is not None and cs_old == 1 and cs_new == 0: + self.ss = ss + + elif ptype == 'BITS': + miso = data[2] + for bit in reversed(miso): + self.data = self.data | bit[0] + + self.data <<= 1 |