--- /dev/null
+##
+## This file is part of the sigrok project.
+##
+## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com>
+##
+## 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 link layer protocol decoder
+
+import sigrokdecode as srd
+
+class Decoder(srd.Decoder):
+ api_version = 1
+ id = 'onewire_link'
+ name = '1-Wire link layer'
+ longname = '1-Wire serial communication bus'
+ desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['onewire_link']
+ probes = [
+ {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
+ ]
+ optional_probes = [
+ {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
+ ]
+ options = {
+ 'overdrive' : ['Overdrive', 1],
+ 'cnt_normal_bit' : ['Time (in samplerate periods) for normal mode sample bit' , 0],
+ 'cnt_normal_presence' : ['Time (in samplerate periods) for normal mode sample presence', 0],
+ 'cnt_normal_reset' : ['Time (in samplerate periods) for normal mode reset' , 0],
+ 'cnt_overdrive_bit' : ['Time (in samplerate periods) for overdrive mode sample bit' , 0],
+ 'cnt_overdrive_presence': ['Time (in samplerate periods) for overdrive mode sample presence', 0],
+ 'cnt_overdrive_reset' : ['Time (in samplerate periods) for overdrive mode reset' , 0],
+ }
+ annotations = [
+ ['Link', 'Link layer events (reset, presence, bit slots)'],
+ ]
+
+ def __init__(self, **kwargs):
+ # Common variables
+ self.samplenum = 0
+ # Link layer variables
+ self.state = 'WAIT FOR FALLING EDGE'
+ self.present = 0
+ self.bit = 0
+ self.overdrive = 0
+ self.cmd_cnt = 0
+ # Event timing variables
+ self.fall = 0
+ self.rise = 0
+
+ def start(self, metadata):
+ self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
+ self.out_ann = self.add(srd.OUTPUT_ANN , 'onewire_link')
+
+ # check if samplerate is appropriate
+ self.samplerate = metadata['samplerate']
+ if (self.options['overdrive']):
+ self.put(0, 0, self.out_ann, [0,
+ ['NOTE: Sample rate checks assume overdrive mode.']])
+ if (self.samplerate < 2000000):
+ self.put(0, 0, self.out_ann, [0,
+ ['ERROR: Sampling rate is too low must be above 2MHz for proper overdrive mode decoding.']])
+ elif (self.samplerate < 5000000):
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: Sampling rate is suggested to be above 5MHz for proper overdrive mode decoding.']])
+ else:
+ self.put(0, 0, self.out_ann, [0,
+ ['NOTE: Sample rate checks assume normal mode only.']])
+ if (self.samplerate < 400000):
+ self.put(0, 0, self.out_ann, [0,
+ ['ERROR: Sampling rate is too low must be above 400kHz for proper normal mode decoding.']])
+ elif (self.samplerate < 1000000):
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: Sampling rate is suggested to be above 1MHz for proper normal mode decoding.']])
+
+ # The default 1-Wire time base is 30us, this is used to calculate sampling times.
+ if (self.options['cnt_normal_bit']):
+ self.cnt_normal_bit = self.options['cnt_normal_bit']
+ else:
+ self.cnt_normal_bit = int(float(self.samplerate) * 0.000015) - 1 # 15ns
+ if (self.options['cnt_normal_presence']):
+ self.cnt_normal_presence = self.options['cnt_normal_presence']
+ else:
+ self.cnt_normal_presence = int(float(self.samplerate) * 0.000075) - 1 # 75ns
+ if (self.options['cnt_normal_reset']):
+ self.cnt_normal_reset = self.options['cnt_normal_reset']
+ else:
+ self.cnt_normal_reset = int(float(self.samplerate) * 0.000480) - 1 # 480ns
+ if (self.options['cnt_overdrive_bit']):
+ self.cnt_overdrive_bit = self.options['cnt_overdrive_bit']
+ else:
+ self.cnt_overdrive_bit = int(float(self.samplerate) * 0.000002) - 1 # 2ns
+ if (self.options['cnt_overdrive_presence']):
+ self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
+ else:
+ self.cnt_overdrive_presence = int(float(self.samplerate) * 0.000010) - 1 # 10ns
+ if (self.options['cnt_overdrive_reset']):
+ self.cnt_overdrive_reset = self.options['cnt_overdrive_reset']
+ else:
+ self.cnt_overdrive_reset = int(float(self.samplerate) * 0.000048) - 1 # 48ns
+
+ # calculating the slot size
+ self.cnt_normal_slot = int(float(self.samplerate) * 0.000060) - 1 # 60ns
+ self.cnt_overdrive_slot = int(float(self.samplerate) * 0.000006) - 1 # 6ns
+
+ # organize values into lists
+ self.cnt_bit = [self.cnt_normal_bit , self.cnt_overdrive_bit ]
+ self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
+ self.cnt_reset = [self.cnt_normal_reset , self.cnt_overdrive_reset ]
+ self.cnt_slot = [self.cnt_normal_slot , self.cnt_overdrive_slot ]
+
+ # Check if sample times are in the allowed range
+ time_min = float(self.cnt_normal_bit ) / self.samplerate
+ time_max = float(self.cnt_normal_bit+1) / self.samplerate
+ if ( (time_min < 0.000005) or (time_max > 0.000015) ) :
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: The normal mode data sample time interval (%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
+ % (time_min*1000000, time_max*1000000)]])
+ time_min = float(self.cnt_normal_presence ) / self.samplerate
+ time_max = float(self.cnt_normal_presence+1) / self.samplerate
+ if ( (time_min < 0.0000681) or (time_max > 0.000075) ) :
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: The normal mode presence sample time interval (%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
+ % (time_min*1000000, time_max*1000000)]])
+ time_min = float(self.cnt_overdrive_bit ) / self.samplerate
+ time_max = float(self.cnt_overdrive_bit+1) / self.samplerate
+ if ( (time_min < 0.000001) or (time_max > 0.000002) ) :
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: The overdrive mode data sample time interval (%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
+ % (time_min*1000000, time_max*1000000)]])
+ time_min = float(self.cnt_overdrive_presence ) / self.samplerate
+ time_max = float(self.cnt_overdrive_presence+1) / self.samplerate
+ if ( (time_min < 0.0000073) or (time_max > 0.000010) ) :
+ self.put(0, 0, self.out_ann, [0,
+ ['WARNING: The overdrive mode presence sample time interval (%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
+ % (time_min*1000000, time_max*1000000)]])
+
+ def report(self):
+ pass
+
+ def decode(self, ss, es, data):
+ for (self.samplenum, (owr, pwr)) in data:
+
+ # State machine.
+ if self.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.fall = self.samplenum
+ # Go to waiting for sample time
+ self.state = 'WAIT FOR DATA SAMPLE'
+ elif self.state == 'WAIT FOR DATA SAMPLE':
+ # Sample data bit
+ if (self.samplenum - self.fall == self.cnt_bit[self.overdrive]):
+ self.bit = owr & 0x1
+ if (self.bit): self.state = 'WAIT FOR FALLING EDGE'
+ else : self.state = 'WAIT FOR RISING EDGE'
+ self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['BIT: %01x' % self.bit]])
+ self.put(self.out_proto, ['BIT', self.bit])
+ # Checking the first command to see if overdrive mode should be entered
+ if (self.cmd_cnt <= 8):
+ self.command = self.command | (self.bit << self.cmd_cnt)
+ elif (self.cmd_cnt == 8):
+ if (self.command in [0x3c, 0x69]):
+ self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['ENTER OVERDRIVE MODE']])
+ # incrementing the bit counter
+ self.bit_cnt += 1
+ elif self.state == 'WAIT FOR RISING EDGE':
+ # The end of a cycle is a rising edge.
+ if (owr == 1):
+ # Check if this was a reset cycle
+ if (self.samplenum - self.fall > self.cnt_normal_reset):
+ # Save the sample number for the falling edge.
+ self.rise = self.samplenum
+ self.state = "WAIT FOR PRESENCE DETECT"
+ self.put(self.fall, self.rise, self.out_ann, [0, ['RESET']])
+ self.put(self.fall, self.rise, self.out_proto, ['RESET', 0])
+ # Reset the timer.
+ self.fall = self.samplenum
+ # Exit overdrive mode
+ self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['EXIT OVERDRIVE MODE']])
+ self.overdrive = 0
+ self.cmd_cnt = 0
+ self.command = 0
+ elif ((self.samplenum - self.fall > self.cnt_overdrive_reset) and (self.overdrive)):
+ # Save the sample number for the falling edge.
+ self.rise = self.samplenum
+ self.state = "WAIT FOR PRESENCE DETECT"
+ self.put(self.fall, self.rise, self.out_ann, [0, ['RESET']])
+ self.put(self.fall, self.rise, self.out_proto, ['RESET', 0])
+ # Reset the timer.
+ self.fall = self.samplenum
+ # Otherwise this is assumed to be a data bit.
+ else :
+ self.state = "WAIT FOR FALLING EDGE"
+ elif self.state == 'WAIT FOR PRESENCE DETECT':
+ # Sample presence status
+ if (self.samplenum - self.rise == self.cnt_presence[self.overdrive]):
+ self.present = owr & 0x1
+ # Save the sample number for the falling edge.
+ if not (self.present) : self.fall = self.samplenum
+ # create presence detect event
+ if (self.present) : self.state = 'WAIT FOR FALLING EDGE'
+ else : self.state = 'WAIT FOR RISING EDGE'
+ self.put(self.samplenum, 0, self.out_ann, [0, ['PRESENCE: ' + "False" if self.present else "True"]])
+ self.put(self.samplenum, 0, self.out_proto, ['PRESENCE', self.present])
+ else:
+ raise Exception('Invalid state: %d' % self.state)
projects / libsigrokdecode.git / blobdiff