## ## This file is part of the sigrok 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 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.bit_cnt = 0 self.command = 0 self.overdrive = 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.fall, self.cnt_bit[self.overdrive], self.out_proto, ['BIT', self.bit]) # Checking the first command to see if overdrive mode should be entered if (self.bit_cnt <= 8): self.command = self.command | (self.bit << self.bit_cnt) elif (self.bit_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" # Reset the timer. self.fall = self.samplenum # Exit overdrive mode if (self.overdrive): self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['EXIT OVERDRIVE MODE']]) self.overdrive = 0 # Clear command bit counter and data register self.bit_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" # 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, ['RESET/PRESENCE: %s' % ('False' if self.present else 'True')]]) self.put(self.samplenum, 0, self.out_proto, ['RESET/PRESENCE', not self.present]) else: raise Exception('Invalid state: %d' % self.state)