## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2012 Iztok Jeras ## ## 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 (link layer) 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 (link layer)' desc = 'Bidirectional, half-duplex, asynchronous serial bus.' license = 'gplv2+' inputs = ['logic'] outputs = ['onewire_link'] probes = [ {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire signal line'}, ] optional_probes = [ {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power supply pin'}, ] options = { 'overdrive': ['Overdrive', 1], # Time options (specified in microseconds): 'cnt_normal_bit': ['Normal mode sample bit time (us)', 15], 'cnt_normal_slot': ['Normal mode data slot time (us)', 60], 'cnt_normal_presence': ['Normal mode sample presence time (us)', 75], 'cnt_normal_reset': ['Normal mode reset time (us)', 480], 'cnt_overdrive_bit': ['Overdrive mode sample bit time (us)', 2], # 'cnt_overdrive_slot': ['Overdrive mode data slot time (us)', 7.3], 'cnt_overdrive_slot': ['Overdrive mode data slot time (us)', 7], 'cnt_overdrive_presence': ['Overdrive mode sample presence time (us)', 10], 'cnt_overdrive_reset': ['Overdrive mode reset time (us)', 48], } annotations = [ ['bit', 'Bit'], ['warnings', 'Warnings'], ['reset', 'Reset/presence'], ['overdrive', 'Overdrive mode notifications'], ] def putm(self, data): self.put(0, 0, self.out_ann, data) def putpb(self, data): self.put(self.fall, self.samplenum, self.out_proto, data) def putb(self, data): self.put(self.fall, self.samplenum, self.out_ann, data) def putx(self, data): self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, data) def __init__(self, **kwargs): self.samplenum = 0 self.state = 'WAIT FOR FALLING EDGE' self.present = 0 self.bit = 0 self.bit_cnt = 0 self.command = 0 self.overdrive = 0 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') self.samplerate = metadata['samplerate'] # Check if samplerate is appropriate. if self.options['overdrive']: if self.samplerate < 2000000: self.putm([1, ['Sampling rate is too low. Must be above ' + '2MHz for proper overdrive mode decoding.']]) elif self.samplerate < 5000000: self.putm([1, ['Sampling rate is suggested to be above 5MHz ' + 'for proper overdrive mode decoding.']]) else: if self.samplerate < 400000: self.putm([1, ['Sampling rate is too low. Must be above ' + '400kHz for proper normal mode decoding.']]) elif (self.samplerate < 1000000): self.putm([1, ['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. samplerate = float(self.samplerate) x = float(self.options['cnt_normal_bit']) / 1000000.0 self.cnt_normal_bit = int(samplerate * x) - 1 x = float(self.options['cnt_normal_slot']) / 1000000.0 self.cnt_normal_slot = int(samplerate * x) - 1 x = float(self.options['cnt_normal_presence']) / 1000000.0 self.cnt_normal_presence = int(samplerate * x) - 1 x = float(self.options['cnt_normal_reset']) / 1000000.0 self.cnt_normal_reset = int(samplerate * x) - 1 x = float(self.options['cnt_overdrive_bit']) / 1000000.0 self.cnt_overdrive_bit = int(samplerate * x) - 1 x = float(self.options['cnt_overdrive_slot']) / 1000000.0 self.cnt_overdrive_slot = int(samplerate * x) - 1 x = float(self.options['cnt_overdrive_presence']) / 1000000.0 self.cnt_overdrive_presence = int(samplerate * x) - 1 x = float(self.options['cnt_overdrive_reset']) / 1000000.0 self.cnt_overdrive_reset = int(samplerate * x) - 1 # 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.putm([1, ['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.putm([1, ['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.putm([1, ['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.putm([1, ['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: continue # 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. t = self.samplenum - self.fall if t == self.cnt_bit[self.overdrive]: self.bit = owr self.state = 'WAIT FOR DATA SLOT END' elif self.state == 'WAIT FOR DATA SLOT END': # A data slot ends in a recovery period, otherwise, this is # probably a reset. t = self.samplenum - self.fall if t != self.cnt_slot[self.overdrive]: continue if owr == 0: # This seems to be a reset slot, wait for its end. self.state = 'WAIT FOR RISING EDGE' continue self.putb([0, ['Bit: %d' % self.bit]]) self.putpb(['BIT', self.bit]) # Checking the first command to see if overdrive mode # should be entered. if self.bit_cnt <= 8: self.command |= (self.bit << self.bit_cnt) elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]: self.putx([3, ['Entering overdrive mode']]) # Increment the bit counter. self.bit_cnt += 1 # Wait for next slot. self.state = 'WAIT FOR FALLING EDGE' elif self.state == 'WAIT FOR RISING EDGE': # The end of a cycle is a rising edge. if owr != 1: continue # Check if this was a reset cycle. t = self.samplenum - self.fall if t > self.cnt_normal_reset: # Save the sample number for the falling edge. self.rise = self.samplenum self.state = 'WAIT FOR PRESENCE DETECT' # Exit overdrive mode. if self.overdrive: self.putx([3, ['Exiting overdrive mode']]) self.overdrive = 0 # Clear command bit counter and data register. self.bit_cnt = 0 self.command = 0 elif (t > 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" # 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. t = self.samplenum - self.rise if t == self.cnt_presence[self.overdrive]: self.present = owr self.state = 'WAIT FOR RESET SLOT END' elif self.state == 'WAIT FOR RESET SLOT END': # A reset slot ends in a long recovery period. t = self.samplenum - self.rise if t != self.cnt_reset[self.overdrive]: continue if owr == 0: # This seems to be a reset slot, wait for its end. self.state = 'WAIT FOR RISING EDGE' continue p = 'false' if self.present else 'true' self.putb([2, ['Reset/presence: %s' % p]]) self.putpb(['RESET/PRESENCE', not self.present]) # Wait for next slot. self.state = 'WAIT FOR FALLING EDGE' else: raise Exception('Invalid state: %s' % self.state)