--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2020 Soeren Apel <soeren@apelpie.net>
+##
+## 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
+from common.srdhelper import bitpack
+import decimal
+
+'''
+OUTPUT_PYTHON format:
+
+[<data>] where <data> is the payload contained between the LFAST header and
+the LFAST stop bit. It's an array of bytes.
+'''
+
+ann_bit, ann_sync, ann_header, ann_payload, ann_stopbit, ann_warning = range(6)
+state_sync, state_header, state_payload, state_stopbit = range(4)
+
+class Decoder(srd.Decoder):
+ api_version = 3
+ id = 'lfast'
+ name = 'LFAST'
+ longname = 'NXP LFAST interface'
+ desc = 'Differential high-speed P2P interface'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['lfast']
+ tags = ['Embedded/industrial']
+ channels = (
+ {'id': 'data', 'name': 'Data', 'desc': 'TXP or RXP'},
+ )
+ annotations = (
+ ('bit', 'Bits'),
+ ('sync', 'Sync Pattern'),
+ ('header', 'Header'),
+ ('payload', 'Payload'),
+ ('stop', 'Stop Bit'),
+ ('warning', 'Warning'),
+ )
+ annotation_rows = (
+ ('bits', 'Bits', (ann_bit,)),
+ ('fields', 'Fields', (ann_sync, ann_header, ann_payload, ann_stopbit,)),
+ ('warnings', 'Warnings', (ann_warning,)),
+ )
+
+ def __init__(self):
+ decimal.getcontext().rounding = decimal.ROUND_HALF_UP
+ self.reset()
+
+ def reset(self):
+ self.ss = self.es = 0
+ self.ss_payload = self.es_payload = 0
+ self.bits = []
+ self.payload = []
+ self.bit_len = 0
+ self.timeout = 0
+ self.state = state_sync
+
+ def metadata(self, key, value):
+ pass
+
+ def start(self):
+ self.out_python = self.register(srd.OUTPUT_PYTHON)
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+
+ def put_ann(self, ss, es, ann_class, value):
+ self.put(ss, es, self.out_ann, [ann_class, value])
+
+ def put_payload(self):
+ self.put(self.ss_payload, self.es_payload, self.out_python, self.payload)
+
+ def handle_sync(self):
+ if len(self.bits) == 1:
+ self.ss_sync = self.ss_bit
+
+ if len(self.bits) == 16:
+ value = bitpack(self.bits)
+ if value == 0xA84B:
+ self.put_ann(self.ss_sync, self.es_bit, ann_sync, ['Sync OK'])
+ else:
+ self.put_ann(self.ss_sync, self.es_bit, ann_warning, ['Wrong Sync Value: {:2X}'.format(value)])
+
+ self.bits = []
+ self.state = state_header
+
+ def handle_header(self):
+ if len(self.bits) == 1:
+ self.ss_header = self.ss_bit
+
+ if len(self.bits) == 8:
+ value = bitpack(self.bits)
+ self.put_ann(self.ss_header, self.es_bit, ann_header, ['{:2X}'.format(value)])
+ self.bits = []
+ self.state = state_payload
+
+ def handle_payload(self):
+ # 8 bit times without state change are possible (8 low bits) but when
+ # there are 9 bit times without state change, we should have seen the
+ # stop bit - and only the stop bit
+ self.timeout = int(9 * self.bit_len)
+
+ if len(self.bits) == 1:
+ self.ss_byte = self.ss_bit
+ if self.ss_payload == 0:
+ self.ss_payload = self.ss_bit
+
+ if len(self.bits) == 8:
+ value = bitpack(self.bits)
+ self.put_ann(self.ss_byte, self.es_bit, ann_payload, ['{:2X}'.format(value)])
+ self.bits = []
+ self.payload.append(value)
+ self.es_payload = self.es_bit
+
+ def handle_stopbit(self):
+ if len(self.bits) > 1:
+ self.put_ann(self.ss_bit, self.es_bit, ann_warning, ['Expected only the stop bit, got {} bits'.format(len(self.bits))])
+ else:
+ if self.bits[0] == 1:
+ self.put_ann(self.ss_bit, self.es_bit, ann_stopbit, ['Stop Bit', 'Stop', 'S'])
+ else:
+ self.put_ann(self.ss_bit, self.es_bit, ann_warning, ['Stop Bit must be 1', 'Stop not 1', 'S'])
+
+ # We send the payload out regardless of the stop bit's status so that
+ # any intermediate results can be decoded by a stacked decoder
+ self.put_payload()
+ self.payload = []
+ self.ss_payload = 0
+
+ self.timeout = 0
+ self.bits = []
+ self.state = state_sync
+
+ def decode(self):
+ while True:
+ if self.timeout == 0:
+ rising_edge, = self.wait({0: 'e'})
+ else:
+ rising_edge, = self.wait([{0: 'e'}, {'skip': self.timeout}])
+
+ # If this is the first bit, we only update ss
+ if self.ss == 0:
+ self.ss = self.samplenum
+ continue
+
+ self.es = self.samplenum
+
+ # Check for the stop bit if this is a timeout condition
+ if (self.timeout > 0) and (self.es - self.ss >= self.timeout):
+ self.handle_stopbit()
+ continue
+
+ # We use the first bit to deduce the bit length
+ if self.bit_len == 0:
+ self.bit_len = self.es - self.ss
+
+ # Determine number of bits covered by this edge
+ bit_count = (self.es - self.ss) / self.bit_len
+ bit_count = int(decimal.Decimal(bit_count).to_integral_value())
+
+ bit_value = '0' if rising_edge else '1'
+
+ divided_len = (self.es - self.ss) / bit_count
+ for i in range(bit_count):
+ self.ss_bit = int(self.ss + i * divided_len)
+ self.es_bit = int(self.ss_bit + divided_len)
+ self.put_ann(self.ss_bit, self.es_bit, ann_bit, [bit_value])
+
+ # Place the new bit at the front of the bit list
+ self.bits.insert(0, (0 if rising_edge else 1))
+
+ if self.state == state_sync:
+ self.handle_sync()
+ elif self.state == state_header:
+ self.handle_header()
+ elif self.state == state_payload:
+ self.handle_payload()
+
+ self.ss = self.samplenum
projects / libsigrokdecode.git / commitdiff