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##
## This file is part of the sigrok project.
##
## Copyright (C) 2011-2012 Uwe Hermann <uwe@hermann-uwe.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, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
##
# 1-Wire protocol decoder
import sigrokdecode as srd
# Annotation feed formats
ANN_ASCII = 0
ANN_DEC = 1
ANN_HEX = 2
ANN_OCT = 3
ANN_BITS = 4
class Decoder(srd.Decoder):
api_version = 1
id = 'onewire'
name = '1-Wire'
longname = ''
desc = '1-Wire bus and MicroLan'
license = 'gplv2+'
inputs = ['logic']
outputs = ['onewire']
probes = [
{'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
]
optional_probes = [
{'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
]
options = {
'overdrive': ['Overdrive', 0],
}
annotations = [
['ASCII', 'Data bytes as ASCII characters'],
['Decimal', 'Databytes as decimal, integer values'],
['Hex', 'Data bytes in hex format'],
['Octal', 'Data bytes as octal numbers'],
['Bits', 'Data bytes in bit notation (sequence of 0/1 digits)'],
]
def __init__(self, **kwargs):
# Common variables
self.samplenum = 0
# Link layer variables
self.lnk_state = 'WAIT FOR FALLING EDGE'
self.lnk_event = 'NONE'
self.lnk_fall = 0
self.lnk_present = 0
self.lnk_bit = 0
# Network layer variables
self.net_state = 'WAIT FOR COMMAND'
self.net_event = 'NONE'
self.net_cnt = 0
self.net_cmd = 0
# Transport layer variables
self.trn_state = 'WAIT FOR EVENT'
self.trn_event = 'NONE'
def start(self, metadata):
self.samplerate = metadata['samplerate']
self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire')
self.out_ann = self.add(srd.OUTPUT_ANN , 'onewire')
# The width of the 1-Wire time base (30us) in number of samples.
# TODO: optimize this value
self.time_base = float(self.samplerate) * float(0.000030)
print ("DEBUG: samplerate = %d, time_base = %d" % (self.samplerate, self.time_base))
def report(self):
pass
def decode(self, ss, es, data):
for (self.samplenum, (owr, pwr)) in data:
# print ("DEBUG: sample = %d, owr = %d, pwr = %d, lnk_fall = %d, lnk_state = %s" % (self.samplenum, owr, pwr, self.lnk_fall, self.lnk_state))
# Data link layer
# Clear events.
self.lnk_event = "NONE"
# State machine.
if self.lnk_state == 'WAIT FOR FALLING EDGE':
# The start of a cycle is a falling edge.
if (owr == 0):
# Save the sample number for the falling edge.
self.lnk_fall = self.samplenum
# Go to waiting for sample time
self.lnk_state = 'WAIT FOR DATA SAMPLE'
self.put(self.lnk_fall, self.samplenum, self.out_ann,
[ANN_DEC, ['LNK: NEGEDGE: ']])
print ("DEBUG: NEGEDGE t0=%d t+=%d" % (self.lnk_fall, self.samplenum))
elif self.lnk_state == 'WAIT FOR DATA SAMPLE':
# Data should be sample one 'time unit' after a falling edge
if (self.samplenum - self.lnk_fall == 1*self.time_base):
self.lnk_bit = owr & 0x1
self.lnk_event = "DATA BIT"
if (self.lnk_bit) : self.lnk_state = 'WAIT FOR FALLING EDGE'
else : self.lnk_state = 'WAIT FOR RISING EDGE'
self.put(self.lnk_fall, self.samplenum, self.out_ann,
[ANN_DEC, ['LNK: BIT: ' + str(self.lnk_bit)]])
print ("DEBUG: BIT=%d t0=%d t+=%d" % (self.lnk_bit, self.lnk_fall, self.samplenum))
elif self.lnk_state == 'WAIT FOR RISING EDGE':
# The end of a cycle is a rising edge.
if (owr == 1):
# A reset cycle is longer than 8T.
if (self.samplenum - self.lnk_fall > 8*self.time_base):
# Save the sample number for the falling edge.
self.lnk_rise = self.samplenum
# Send a reset event to the next protocol layer.
self.lnk_event = "RESET"
self.lnk_state = "WAIT FOR PRESENCE DETECT"
self.put(self.lnk_fall, self.samplenum, self.out_proto,
['RESET'])
self.put(self.lnk_fall, self.samplenum, self.out_ann,
[ANN_DEC, ['LNK: RESET: ']])
print ("DEBUG: RESET t0=%d t+=%d" % (self.lnk_fall, self.samplenum))
# Reset the timer.
self.lnk_fall = self.samplenum
# Otherwise this is assumed to be a data bit.
else :
self.lnk_state = "WAIT FOR FALLING EDGE"
elif self.lnk_state == 'WAIT FOR PRESENCE DETECT':
# Data should be sample one 'time unit' after a falling edge
if (self.samplenum - self.lnk_rise == 2.5*self.time_base):
self.lnk_present = owr & 0x1
#self.lnk_event = "PRESENCE DETECT"
if (self.lnk_bit) : self.lnk_state = 'WAIT FOR FALLING EDGE'
else : self.lnk_state = 'WAIT FOR RISING EDGE'
self.put(self.lnk_fall, self.samplenum, self.out_ann,
[ANN_DEC, ['LNK: PRESENCE: ' + str(self.lnk_present)]])
print ("DEBUG: PRESENCE=%d t0=%d t+=%d" % (self.lnk_present, self.lnk_fall, self.samplenum))
else:
raise Exception('Invalid lnk_state: %d' % self.lnk_state)
# Network layer
# Clear events.
self.net_event = "RESET"
# State machine.
if (self.lnk_event == "RESET"):
self.net_state = "WAIT FOR COMMAND"
self.net_cnt = 0
self.net_cmd = 0
elif (self.lnk_event == "DATA BIT"):
if (self.net_state == "WAIT FOR COMMAND"):
self.net_cnt = self.net_cnt + 1
self.net_cmd = (self.net_cmd << 1) & self.lnk_bit
if (self.net_cnt == 8):
self.put(self.lnk_fall, self.samplenum,
self.out_proto, ['LNK: COMMAND', self.net_cmd])
self.put(self.lnk_fall, self.samplenum, self.out_ann,
[ANN_DEC, ['LNK: COMMAND: ' + self.net_cmd]])
if (self.net_cmd == 0x33):
# READ ROM
break
elif (self.net_cmd == 0x0f):
# READ ROM
break
elif (self.net_cmd == 0xcc):
# SKIP ROM
break
elif (self.net_cmd == 0x55):
# MATCH ROM
break
elif (self.net_cmd == 0xf0):
# SEARCH ROM
break
elif (self.net_cmd == 0x3c):
# OVERDRIVE SKIP ROM
break
elif (self.net_cmd == 0x69):
# OVERDRIVE MATCH ROM
break
self.net_cnt = 0
elif (self.net_state == "WAIT FOR ROM"):
#
break
else:
raise Exception('Invalid net_state: %d' % self.net_state)
elif not (self.lnk_event == "NONE"):
raise Exception('Invalid lnk_event: %s' % self.lnk_event)
# if (self.samplenum == self.lnk_start + 8*self.time_base):
# self.put(self.lnk_fall, self.samplenum - 1, self.out_proto, ['RESET'])
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