mirror of
https://github.com/gusmanb/logicanalyzer.git
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636 lines
26 KiB
Python
636 lines
26 KiB
Python
##
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## This file is part of the libsigrokdecode project.
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##
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## Copyright (C) 2011-2014 Uwe Hermann <uwe@hermann-uwe.de>
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##
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## This program is free software; you can redistribute it and/or modify
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## it under the terms of the GNU General Public License as published by
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## the Free Software Foundation; either version 2 of the License, or
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## (at your option) any later version.
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##
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## This program is distributed in the hope that it will be useful,
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## but WITHOUT ANY WARRANTY; without even the implied warranty of
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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## GNU General Public License for more details.
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##
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## You should have received a copy of the GNU General Public License
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## along with this program; if not, see <http://www.gnu.org/licenses/>.
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##
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import sigrokdecode as srd
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from common.srdhelper import bitpack
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from math import floor, ceil
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'''
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OUTPUT_PYTHON format:
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Packet:
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[<ptype>, <rxtx>, <pdata>]
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This is the list of <ptype>s and their respective <pdata> values:
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- 'STARTBIT': The data is the (integer) value of the start bit (0/1).
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- 'DATA': This is always a tuple containing two items:
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- 1st item: the (integer) value of the UART data. Valid values
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range from 0 to 511 (as the data can be up to 9 bits in size).
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- 2nd item: the list of individual data bits and their ss/es numbers.
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- 'PARITYBIT': The data is the (integer) value of the parity bit (0/1).
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- 'STOPBIT': The data is the (integer) value of the stop bit (0 or 1).
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- 'INVALID STARTBIT': The data is the (integer) value of the start bit (0/1).
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- 'INVALID STOPBIT': The data is the (integer) value of the stop bit (0/1).
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- 'PARITY ERROR': The data is a tuple with two entries. The first one is
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the expected parity value, the second is the actual parity value.
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- 'BREAK': The data is always 0.
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- 'FRAME': The data is always a tuple containing two items: The (integer)
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value of the UART data, and a boolean which reflects the validity of the
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UART frame.
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- 'IDLE': The data is always 0.
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The <rxtx> field is 0 for RX packets, 1 for TX packets.
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'''
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# Used for differentiating between the two data directions.
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RX = 0
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TX = 1
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# Given a parity type to check (odd, even, zero, one), the value of the
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# parity bit, the value of the data, and the length of the data (5-9 bits,
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# usually 8 bits) return True if the parity is correct, False otherwise.
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# 'none' is _not_ allowed as value for 'parity_type'.
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def parity_ok(parity_type, parity_bit, data, data_bits):
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if parity_type == 'ignore':
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return True
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# Handle easy cases first (parity bit is always 1 or 0).
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if parity_type == 'zero':
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return parity_bit == 0
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elif parity_type == 'one':
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return parity_bit == 1
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# Count number of 1 (high) bits in the data (and the parity bit itself!).
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ones = bin(data).count('1') + parity_bit
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# Check for odd/even parity.
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if parity_type == 'odd':
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return (ones % 2) == 1
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elif parity_type == 'even':
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return (ones % 2) == 0
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class SamplerateError(Exception):
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pass
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class ChannelError(Exception):
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pass
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class Ann:
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RX_DATA, TX_DATA, RX_START, TX_START, RX_PARITY_OK, TX_PARITY_OK, \
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RX_PARITY_ERR, TX_PARITY_ERR, RX_STOP, TX_STOP, RX_WARN, TX_WARN, \
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RX_DATA_BIT, TX_DATA_BIT, RX_BREAK, TX_BREAK, RX_PACKET, TX_PACKET = \
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range(18)
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class Bin:
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RX, TX, RXTX = range(3)
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class Decoder(srd.Decoder):
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api_version = 3
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id = 'uart'
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name = 'UART'
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longname = 'Universal Asynchronous Receiver/Transmitter'
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desc = 'Asynchronous, serial bus.'
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license = 'gplv2+'
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inputs = ['logic']
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outputs = ['uart']
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tags = ['Embedded/industrial']
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optional_channels = (
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# Allow specifying only one of the signals, e.g. if only one data
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# direction exists (or is relevant).
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{'id': 'rx', 'name': 'RX', 'desc': 'UART receive line'},
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{'id': 'tx', 'name': 'TX', 'desc': 'UART transmit line'},
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)
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options = (
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{'id': 'baudrate', 'desc': 'Baud rate', 'default': 115200},
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{'id': 'data_bits', 'desc': 'Data bits', 'default': 8,
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'values': (5, 6, 7, 8, 9)},
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{'id': 'parity', 'desc': 'Parity', 'default': 'none',
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'values': ('none', 'odd', 'even', 'zero', 'one', 'ignore')},
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{'id': 'stop_bits', 'desc': 'Stop bits', 'default': 1.0,
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'values': (0.0, 0.5, 1.0, 1.5, 2.0)},
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{'id': 'bit_order', 'desc': 'Bit order', 'default': 'lsb-first',
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'values': ('lsb-first', 'msb-first')},
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{'id': 'format', 'desc': 'Data format', 'default': 'hex',
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'values': ('ascii', 'dec', 'hex', 'oct', 'bin')},
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{'id': 'invert_rx', 'desc': 'Invert RX', 'default': 'no',
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'values': ('yes', 'no')},
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{'id': 'invert_tx', 'desc': 'Invert TX', 'default': 'no',
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'values': ('yes', 'no')},
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{'id': 'sample_point', 'desc': 'Sample point (%)', 'default': 50},
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{'id': 'rx_packet_delim', 'desc': 'RX packet delimiter (decimal)',
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'default': -1},
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{'id': 'tx_packet_delim', 'desc': 'TX packet delimiter (decimal)',
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'default': -1},
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{'id': 'rx_packet_len', 'desc': 'RX packet length', 'default': -1},
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{'id': 'tx_packet_len', 'desc': 'TX packet length', 'default': -1},
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)
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annotations = (
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('rx-data', 'RX data'),
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('tx-data', 'TX data'),
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('rx-start', 'RX start bit'),
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('tx-start', 'TX start bit'),
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('rx-parity-ok', 'RX parity OK bit'),
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('tx-parity-ok', 'TX parity OK bit'),
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('rx-parity-err', 'RX parity error bit'),
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('tx-parity-err', 'TX parity error bit'),
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('rx-stop', 'RX stop bit'),
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('tx-stop', 'TX stop bit'),
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('rx-warning', 'RX warning'),
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('tx-warning', 'TX warning'),
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('rx-data-bit', 'RX data bit'),
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('tx-data-bit', 'TX data bit'),
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('rx-break', 'RX break'),
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('tx-break', 'TX break'),
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('rx-packet', 'RX packet'),
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('tx-packet', 'TX packet'),
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)
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annotation_rows = (
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('rx-data-bits', 'RX bits', (Ann.RX_DATA_BIT,)),
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('rx-data-vals', 'RX data', (Ann.RX_DATA, Ann.RX_START, Ann.RX_PARITY_OK, Ann.RX_PARITY_ERR, Ann.RX_STOP)),
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('rx-warnings', 'RX warnings', (Ann.RX_WARN,)),
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('rx-breaks', 'RX breaks', (Ann.RX_BREAK,)),
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('rx-packets', 'RX packets', (Ann.RX_PACKET,)),
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('tx-data-bits', 'TX bits', (Ann.TX_DATA_BIT,)),
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('tx-data-vals', 'TX data', (Ann.TX_DATA, Ann.TX_START, Ann.TX_PARITY_OK, Ann.TX_PARITY_ERR, Ann.TX_STOP)),
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('tx-warnings', 'TX warnings', (Ann.TX_WARN,)),
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('tx-breaks', 'TX breaks', (Ann.TX_BREAK,)),
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('tx-packets', 'TX packets', (Ann.TX_PACKET,)),
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)
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binary = (
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('rx', 'RX dump'),
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('tx', 'TX dump'),
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('rxtx', 'RX/TX dump'),
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)
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idle_state = ['WAIT FOR START BIT', 'WAIT FOR START BIT']
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def putx(self, rxtx, data):
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s, halfbit = self.startsample[rxtx], self.bit_width / 2.0
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self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_ann, data)
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def putx_packet(self, rxtx, data):
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s, halfbit = self.ss_packet[rxtx], self.bit_width / 2.0
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self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_ann, data)
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def putpx(self, rxtx, data):
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s, halfbit = self.startsample[rxtx], self.bit_width / 2.0
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self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_python, data)
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def putg(self, data):
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s, halfbit = self.samplenum, self.bit_width / 2.0
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self.put(s - floor(halfbit), s + ceil(halfbit), self.out_ann, data)
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def putp(self, data):
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s, halfbit = self.samplenum, self.bit_width / 2.0
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self.put(s - floor(halfbit), s + ceil(halfbit), self.out_python, data)
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def putgse(self, ss, es, data):
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self.put(ss, es, self.out_ann, data)
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def putpse(self, ss, es, data):
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self.put(ss, es, self.out_python, data)
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def putbin(self, rxtx, data):
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s, halfbit = self.startsample[rxtx], self.bit_width / 2.0
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self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_binary, data)
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def __init__(self):
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self.reset()
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def reset(self):
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self.samplerate = None
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self.frame_start = [-1, -1]
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self.frame_valid = [None, None]
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self.cur_frame_bit = [None, None]
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self.startbit = [-1, -1]
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self.cur_data_bit = [0, 0]
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self.datavalue = [0, 0]
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self.paritybit = [-1, -1]
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self.stopbits = [[], []]
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self.startsample = [-1, -1]
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self.state = ['WAIT FOR START BIT', 'WAIT FOR START BIT']
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self.databits = [[], []]
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self.break_start = [None, None]
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self.packet_cache = [[], []]
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self.ss_packet, self.es_packet = [None, None], [None, None]
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self.idle_start = [None, None]
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def start(self):
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self.out_python = self.register(srd.OUTPUT_PYTHON)
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self.out_binary = self.register(srd.OUTPUT_BINARY)
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self.out_ann = self.register(srd.OUTPUT_ANN)
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self.bw = (self.options['data_bits'] + 7) // 8
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def metadata(self, key, value):
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if key == srd.SRD_CONF_SAMPLERATE:
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self.samplerate = value
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# The width of one UART bit in number of samples.
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self.bit_width = float(self.samplerate) / float(self.options['baudrate'])
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def get_sample_point(self, rxtx, bitnum):
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# Determine absolute sample number of a bit slot's sample point.
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# Counts for UART bits start from 0 (0 = start bit, 1..x = data,
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# x+1 = parity bit (if used) or the first stop bit, and so on).
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# Accept a position in the range of 1-99% of the full bit width.
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# Assume 50% for invalid input specs for backwards compatibility.
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perc = self.options['sample_point'] or 50
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if not perc or perc not in range(1, 100):
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perc = 50
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perc /= 100.0
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bitpos = (self.bit_width - 1) * perc
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bitpos += self.frame_start[rxtx]
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bitpos += bitnum * self.bit_width
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return bitpos
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def wait_for_start_bit(self, rxtx, signal):
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# Save the sample number where the start bit begins.
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self.frame_start[rxtx] = self.samplenum
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self.frame_valid[rxtx] = True
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self.cur_frame_bit[rxtx] = 0
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self.advance_state(rxtx, signal)
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def get_start_bit(self, rxtx, signal):
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self.startbit[rxtx] = signal
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self.cur_frame_bit[rxtx] += 1
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# The startbit must be 0. If not, we report an error and wait
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# for the next start bit (assuming this one was spurious).
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if self.startbit[rxtx] != 0:
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self.putp(['INVALID STARTBIT', rxtx, self.startbit[rxtx]])
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self.putg([Ann.RX_WARN + rxtx, ['Frame error', 'Frame err', 'FE']])
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self.frame_valid[rxtx] = False
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es = self.samplenum + ceil(self.bit_width / 2.0)
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self.putpse(self.frame_start[rxtx], es, ['FRAME', rxtx,
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(self.datavalue[rxtx], self.frame_valid[rxtx])])
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self.advance_state(rxtx, signal, fatal = True, idle = es)
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return
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# Reset internal state for the pending UART frame.
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self.cur_data_bit[rxtx] = 0
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self.datavalue[rxtx] = 0
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self.paritybit[rxtx] = -1
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self.stopbits[rxtx].clear()
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self.startsample[rxtx] = -1
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self.databits[rxtx].clear()
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self.putp(['STARTBIT', rxtx, self.startbit[rxtx]])
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self.putg([Ann.RX_START + rxtx, ['Start bit', 'Start', 'S']])
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self.advance_state(rxtx, signal)
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def handle_packet(self, rxtx):
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d = 'rx' if (rxtx == RX) else 'tx'
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delim = self.options[d + '_packet_delim']
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plen = self.options[d + '_packet_len']
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if delim == -1 and plen == -1:
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return
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# Cache data values until we see the delimiter and/or the specified
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# packet length has been reached (whichever happens first).
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if len(self.packet_cache[rxtx]) == 0:
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self.ss_packet[rxtx] = self.startsample[rxtx]
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self.packet_cache[rxtx].append(self.datavalue[rxtx])
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if self.datavalue[rxtx] == delim or len(self.packet_cache[rxtx]) == plen:
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self.es_packet[rxtx] = self.samplenum
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s = ''
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for b in self.packet_cache[rxtx]:
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s += self.format_value(b)
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if self.options['format'] != 'ascii':
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s += ' '
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if self.options['format'] != 'ascii' and s[-1] == ' ':
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s = s[:-1] # Drop trailing space.
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self.putx_packet(rxtx, [Ann.RX_PACKET + rxtx, [s]])
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self.packet_cache[rxtx] = []
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def get_data_bits(self, rxtx, signal):
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# Save the sample number of the middle of the first data bit.
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if self.startsample[rxtx] == -1:
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self.startsample[rxtx] = self.samplenum
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self.putg([Ann.RX_DATA_BIT + rxtx, ['%d' % signal]])
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# Store individual data bits and their start/end samplenumbers.
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s, halfbit = self.samplenum, int(self.bit_width / 2)
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self.databits[rxtx].append([signal, s - halfbit, s + halfbit])
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self.cur_frame_bit[rxtx] += 1
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# Return here, unless we already received all data bits.
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self.cur_data_bit[rxtx] += 1
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if self.cur_data_bit[rxtx] < self.options['data_bits']:
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return
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# Convert accumulated data bits to a data value.
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bits = [b[0] for b in self.databits[rxtx]]
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if self.options['bit_order'] == 'msb-first':
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bits.reverse()
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self.datavalue[rxtx] = bitpack(bits)
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self.putpx(rxtx, ['DATA', rxtx,
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(self.datavalue[rxtx], self.databits[rxtx])])
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b = self.datavalue[rxtx]
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formatted = self.format_value(b)
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if formatted is not None:
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self.putx(rxtx, [rxtx, [formatted]])
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bdata = b.to_bytes(self.bw, byteorder='big')
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self.putbin(rxtx, [Bin.RX + rxtx, bdata])
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self.putbin(rxtx, [Bin.RXTX, bdata])
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self.handle_packet(rxtx)
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self.databits[rxtx] = []
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self.advance_state(rxtx, signal)
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def format_value(self, v):
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# Format value 'v' according to configured options.
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# Reflects the user selected kind of representation, as well as
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# the number of data bits in the UART frames.
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fmt, bits = self.options['format'], self.options['data_bits']
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# Assume "is printable" for values from 32 to including 126,
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# below 32 is "control" and thus not printable, above 127 is
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# "not ASCII" in its strict sense, 127 (DEL) is not printable,
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# fall back to hex representation for non-printables.
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if fmt == 'ascii':
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if v in range(32, 126 + 1):
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return chr(v)
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hexfmt = "[{:02X}]" if bits <= 8 else "[{:03X}]"
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return hexfmt.format(v)
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# Mere number to text conversion without prefix and padding
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# for the "decimal" output format.
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if fmt == 'dec':
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return "{:d}".format(v)
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# Padding with leading zeroes for hex/oct/bin formats, but
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# without a prefix for density -- since the format is user
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# specified, there is no ambiguity.
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if fmt == 'hex':
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digits = (bits + 4 - 1) // 4
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fmtchar = "X"
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elif fmt == 'oct':
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digits = (bits + 3 - 1) // 3
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fmtchar = "o"
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elif fmt == 'bin':
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digits = bits
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fmtchar = "b"
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else:
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fmtchar = None
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if fmtchar is not None:
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fmt = "{{:0{:d}{:s}}}".format(digits, fmtchar)
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return fmt.format(v)
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return None
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def get_parity_bit(self, rxtx, signal):
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self.paritybit[rxtx] = signal
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self.cur_frame_bit[rxtx] += 1
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if parity_ok(self.options['parity'], self.paritybit[rxtx],
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self.datavalue[rxtx], self.options['data_bits']):
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self.putp(['PARITYBIT', rxtx, self.paritybit[rxtx]])
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self.putg([Ann.RX_PARITY_OK + rxtx, ['Parity bit', 'Parity', 'P']])
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else:
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# TODO: Return expected/actual parity values.
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self.putp(['PARITY ERROR', rxtx, (0, 1)]) # FIXME: Dummy tuple...
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self.putg([Ann.RX_PARITY_ERR + rxtx, ['Parity error', 'Parity err', 'PE']])
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self.frame_valid[rxtx] = False
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self.advance_state(rxtx, signal)
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def get_stop_bits(self, rxtx, signal):
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self.stopbits[rxtx].append(signal)
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self.cur_frame_bit[rxtx] += 1
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# Stop bits must be 1. If not, we report an error.
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if signal != 1:
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self.putp(['INVALID STOPBIT', rxtx, signal])
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self.putg([Ann.RX_WARN + rxtx, ['Frame error', 'Frame err', 'FE']])
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self.frame_valid[rxtx] = False
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self.putp(['STOPBIT', rxtx, signal])
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self.putg([Ann.RX_STOP + rxtx, ['Stop bit', 'Stop', 'T']])
|
|
|
|
# Postprocess the UART frame after all STOP bits were seen.
|
|
if len(self.stopbits[rxtx]) < self.options['stop_bits']:
|
|
return
|
|
self.advance_state(rxtx, signal)
|
|
|
|
def advance_state(self, rxtx, signal = None, fatal = False, idle = None):
|
|
# Advances the protocol decoder's internal state for all regular
|
|
# UART frame inspection. Deals with either edges, sample points,
|
|
# or other .wait() conditions. Also gracefully handles extreme
|
|
# undersampling. Each turn takes one .wait() call which in turn
|
|
# corresponds to at least one sample. That is why as many state
|
|
# transitions are done here as required within a single call.
|
|
frame_end = self.frame_start[rxtx] + self.frame_len_sample_count
|
|
if idle is not None:
|
|
# When requested by the caller, start another (potential)
|
|
# IDLE period after the caller specified position.
|
|
self.idle_start[rxtx] = idle
|
|
if fatal:
|
|
# When requested by the caller, don't advance to the next
|
|
# UART frame's field, but to the start of the next START bit
|
|
# instead.
|
|
self.state[rxtx] = 'WAIT FOR START BIT'
|
|
return
|
|
# Advance to the next UART frame's field that we expect. Cope
|
|
# with absence of optional fields. Force scan for next IDLE
|
|
# after the (optional) STOP bit field, so that callers need
|
|
# not deal with optional field presence. Also handles the cases
|
|
# where the decoder navigates to edges which are not strictly
|
|
# a field's sampling point.
|
|
if self.state[rxtx] == 'WAIT FOR START BIT':
|
|
self.state[rxtx] = 'GET START BIT'
|
|
return
|
|
if self.state[rxtx] == 'GET START BIT':
|
|
self.state[rxtx] = 'GET DATA BITS'
|
|
return
|
|
if self.state[rxtx] == 'GET DATA BITS':
|
|
self.state[rxtx] = 'GET PARITY BIT'
|
|
if self.options['parity'] != 'none':
|
|
return
|
|
# FALLTHROUGH
|
|
if self.state[rxtx] == 'GET PARITY BIT':
|
|
self.state[rxtx] = 'GET STOP BITS'
|
|
if self.options['stop_bits']:
|
|
return
|
|
# FALLTHROUGH
|
|
if self.state[rxtx] == 'GET STOP BITS':
|
|
# Postprocess the previously received UART frame. Advance
|
|
# the read position to after the frame's last bit time. So
|
|
# that the start of the next START bit won't fall into the
|
|
# end of the previously received UART frame. This improves
|
|
# robustness in the presence of glitchy input data.
|
|
ss = self.frame_start[rxtx]
|
|
es = self.samplenum + ceil(self.bit_width / 2.0)
|
|
self.handle_frame(rxtx, ss, es)
|
|
self.state[rxtx] = 'WAIT FOR START BIT'
|
|
self.idle_start[rxtx] = frame_end
|
|
return
|
|
# Unhandled state, actually a programming error. Emit diagnostics?
|
|
self.state[rxtx] = 'WAIT FOR START BIT'
|
|
|
|
def handle_frame(self, rxtx, ss, es):
|
|
# Pass the complete UART frame to upper layers.
|
|
self.putpse(ss, es, ['FRAME', rxtx,
|
|
(self.datavalue[rxtx], self.frame_valid[rxtx])])
|
|
|
|
def handle_idle(self, rxtx, ss, es):
|
|
self.putpse(ss, es, ['IDLE', rxtx, 0])
|
|
|
|
def handle_break(self, rxtx, ss, es):
|
|
self.putpse(ss, es, ['BREAK', rxtx, 0])
|
|
self.putgse(ss, es, [Ann.RX_BREAK + rxtx,
|
|
['Break condition', 'Break', 'Brk', 'B']])
|
|
self.state[rxtx] = 'WAIT FOR START BIT'
|
|
|
|
def get_wait_cond(self, rxtx, inv):
|
|
# Return condititions that are suitable for Decoder.wait(). Those
|
|
# conditions either match the falling edge of the START bit, or
|
|
# the sample point of the next bit time.
|
|
state = self.state[rxtx]
|
|
if state == 'WAIT FOR START BIT':
|
|
return {rxtx: 'r' if inv else 'f'}
|
|
if state in ('GET START BIT', 'GET DATA BITS',
|
|
'GET PARITY BIT', 'GET STOP BITS'):
|
|
bitnum = self.cur_frame_bit[rxtx]
|
|
# TODO: Currently does not support half STOP bits.
|
|
want_num = ceil(self.get_sample_point(rxtx, bitnum))
|
|
return {'skip': want_num - self.samplenum}
|
|
|
|
def get_idle_cond(self, rxtx, inv):
|
|
# Return a condition that corresponds to the (expected) end of
|
|
# the next frame, assuming that it will be an "idle frame"
|
|
# (constant high input level for the frame's length).
|
|
if self.idle_start[rxtx] is None:
|
|
return None
|
|
end_of_frame = self.idle_start[rxtx] + self.frame_len_sample_count
|
|
if end_of_frame < self.samplenum:
|
|
return None
|
|
return {'skip': end_of_frame - self.samplenum}
|
|
|
|
def inspect_sample(self, rxtx, signal, inv):
|
|
# Inspect a sample returned by .wait() for the specified UART line.
|
|
if inv:
|
|
signal = not signal
|
|
|
|
state = self.state[rxtx]
|
|
if state == 'WAIT FOR START BIT':
|
|
self.wait_for_start_bit(rxtx, signal)
|
|
elif state == 'GET START BIT':
|
|
self.get_start_bit(rxtx, signal)
|
|
elif state == 'GET DATA BITS':
|
|
self.get_data_bits(rxtx, signal)
|
|
elif state == 'GET PARITY BIT':
|
|
self.get_parity_bit(rxtx, signal)
|
|
elif state == 'GET STOP BITS':
|
|
self.get_stop_bits(rxtx, signal)
|
|
|
|
def inspect_edge(self, rxtx, signal, inv):
|
|
# Inspect edges, independently from traffic, to detect break conditions.
|
|
if inv:
|
|
signal = not signal
|
|
if not signal:
|
|
# Signal went low. Start another interval.
|
|
self.break_start[rxtx] = self.samplenum
|
|
return
|
|
# Signal went high. Was there an extended period with low signal?
|
|
if self.break_start[rxtx] is None:
|
|
return
|
|
diff = self.samplenum - self.break_start[rxtx]
|
|
if diff >= self.break_min_sample_count:
|
|
ss, es = self.frame_start[rxtx], self.samplenum
|
|
self.handle_break(rxtx, ss, es)
|
|
self.break_start[rxtx] = None
|
|
|
|
def inspect_idle(self, rxtx, signal, inv):
|
|
# Check each edge and each period of stable input (either level).
|
|
# Can derive the "idle frame period has passed" condition.
|
|
if inv:
|
|
signal = not signal
|
|
if not signal:
|
|
# Low input, cease inspection.
|
|
self.idle_start[rxtx] = None
|
|
return
|
|
# High input, either just reached, or still stable.
|
|
if self.idle_start[rxtx] is None:
|
|
self.idle_start[rxtx] = self.samplenum
|
|
diff = self.samplenum - self.idle_start[rxtx]
|
|
if diff < self.frame_len_sample_count:
|
|
return
|
|
ss, es = self.idle_start[rxtx], self.samplenum
|
|
self.handle_idle(rxtx, ss, es)
|
|
self.idle_start[rxtx] = es
|
|
|
|
def decode(self):
|
|
if not self.samplerate:
|
|
raise SamplerateError('Cannot decode without samplerate.')
|
|
|
|
has_pin = [self.has_channel(ch) for ch in (RX, TX)]
|
|
if not True in has_pin:
|
|
raise ChannelError('Need at least one of TX or RX pins.')
|
|
|
|
opt = self.options
|
|
inv = [opt['invert_rx'] == 'yes', opt['invert_tx'] == 'yes']
|
|
cond_data_idx = [None] * len(has_pin)
|
|
|
|
# Determine the number of samples for a complete frame's time span.
|
|
# A period of low signal (at least) that long is a break condition.
|
|
frame_samples = 1 # START
|
|
frame_samples += self.options['data_bits']
|
|
frame_samples += 0 if self.options['parity'] == 'none' else 1
|
|
frame_samples += self.options['stop_bits']
|
|
frame_samples *= self.bit_width
|
|
self.frame_len_sample_count = ceil(frame_samples)
|
|
self.break_min_sample_count = self.frame_len_sample_count
|
|
cond_edge_idx = [None] * len(has_pin)
|
|
cond_idle_idx = [None] * len(has_pin)
|
|
|
|
while True:
|
|
conds = []
|
|
if has_pin[RX]:
|
|
cond_data_idx[RX] = len(conds)
|
|
conds.append(self.get_wait_cond(RX, inv[RX]))
|
|
cond_edge_idx[RX] = len(conds)
|
|
conds.append({RX: 'e'})
|
|
cond_idle_idx[RX] = None
|
|
idle_cond = self.get_idle_cond(RX, inv[RX])
|
|
if idle_cond:
|
|
cond_idle_idx[RX] = len(conds)
|
|
conds.append(idle_cond)
|
|
if has_pin[TX]:
|
|
cond_data_idx[TX] = len(conds)
|
|
conds.append(self.get_wait_cond(TX, inv[TX]))
|
|
cond_edge_idx[TX] = len(conds)
|
|
conds.append({TX: 'e'})
|
|
cond_idle_idx[TX] = None
|
|
idle_cond = self.get_idle_cond(TX, inv[TX])
|
|
if idle_cond:
|
|
cond_idle_idx[TX] = len(conds)
|
|
conds.append(idle_cond)
|
|
(rx, tx) = self.wait(conds)
|
|
if cond_data_idx[RX] is not None and self.matched[cond_data_idx[RX]]:
|
|
self.inspect_sample(RX, rx, inv[RX])
|
|
if cond_edge_idx[RX] is not None and self.matched[cond_edge_idx[RX]]:
|
|
self.inspect_edge(RX, rx, inv[RX])
|
|
self.inspect_idle(RX, rx, inv[RX])
|
|
if cond_idle_idx[RX] is not None and self.matched[cond_idle_idx[RX]]:
|
|
self.inspect_idle(RX, rx, inv[RX])
|
|
if cond_data_idx[TX] is not None and self.matched[cond_data_idx[TX]]:
|
|
self.inspect_sample(TX, tx, inv[TX])
|
|
if cond_edge_idx[TX] is not None and self.matched[cond_edge_idx[TX]]:
|
|
self.inspect_edge(TX, tx, inv[TX])
|
|
self.inspect_idle(TX, tx, inv[TX])
|
|
if cond_idle_idx[TX] is not None and self.matched[cond_idle_idx[TX]]:
|
|
self.inspect_idle(TX, tx, inv[TX])
|