From: Uwe Hermann Date: Wed, 18 Jul 2012 20:16:19 +0000 (+0200) Subject: srd: onewire_link: Cosmetics, simplifications, doc fixes. X-Git-Tag: libsigrokdecode-0.1.1~45 X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=e7720d6c73eb981e57753c9028fa3e9019676c50;p=libsigrokdecode.git srd: onewire_link: Cosmetics, simplifications, doc fixes. --- diff --git a/decoders/onewire_link/__init__.py b/decoders/onewire_link/__init__.py index 5c7251d..cb03471 100644 --- a/decoders/onewire_link/__init__.py +++ b/decoders/onewire_link/__init__.py @@ -19,63 +19,73 @@ ## ''' -1-Wire protocol decoder. +1-Wire protocol decoder (link layer). -The 1-Wire protocol enables bidirectional communication over a single wire (and -ground) between a single master and one or multiple slaves. The protocol is -layered. -- Link layer (reset, presence detection, reading/writing bits) -- Network layer (skip/search/match device ROM addresses) -- Transport layer (transport data between 1-Wire master and device) +The 1-Wire protocol enables bidirectional communication over a single wire +(and ground) between a single master and one or multiple slaves. The protocol +is layered: -Link layer + - Link layer (reset, presence detection, reading/writing bits) + - Network layer (skip/search/match device ROM addresses) + - Transport layer (transport data between 1-Wire master and device) + +Link layer protocol details: Sample rate: -A high enough sample rate is required to properly detect all the elements of -the protocol. A lower sample rate can be used if the master does not use -overdrive communication speed. The next minimal values should be used: -- overdrive available: 2MHz minimum, 5MHz suggested -- overdrive not available: 400kHz minimum, 1MHz suggested +A sufficiently high samplerate is required to properly detect all the elements +of the protocol. A lower samplerate can be used if the master does not use +overdrive communication speed. The following minimal values should be used: + + - overdrive available: 2MHz minimum, 5MHz suggested + - overdrive not available: 400kHz minimum, 1MHz suggested Probes: 1-Wire requires a single signal, but some master implementations might have a -separate signal use to deliver power to the bus during temperature conversion -as an example. This power signal is currently not parsed. -- owr (1-Wire bus) -- pwr (1-Wire power) +separate signal used to deliver power to the bus during temperature conversion +as an example. This power signal is currently not used. + + - owr (1-Wire signal line) + - pwr (optional, dedicated power supply pin) Options: -1-Wire is an asynchronous protocol, so the decoder must know the sample rate. -The timing for sampling bits, presence and reset is calculated by the decoder, +1-Wire is an asynchronous protocol, so the decoder must know the samplerate. +The timing for sampling bits, presence, and reset is calculated by the decoder, but in case the user wishes to use different values, it is possible to -configure the next timing values (number of sample rate periods): -- overdrive (if active the decoder will be prepared for overdrive) -- cnt_normal_bit (time for normal mode sample bit) -- cnt_normal_slot (time for normal mode data slot) -- cnt_normal_presence (time for normal mode sample presence) -- cnt_normal_reset (time for normal mode reset) -- cnt_overdrive_bit (time for overdrive mode sample bit) -- cnt_overdrive_slot (time for overdrive mode data slot) -- cnt_overdrive_presence (time for overdrive mode sample presence) -- cnt_overdrive_reset (time for overdrive mode reset) -This options should be configured only on very rare cases and the user should +configure the following timing values (number of samplerate periods): + + - overdrive (if active the decoder will be prepared for overdrive) + - cnt_normal_bit (time for normal mode sample bit) + - cnt_normal_slot (time for normal mode data slot) + - cnt_normal_presence (time for normal mode sample presence) + - cnt_normal_reset (time for normal mode reset) + - cnt_overdrive_bit (time for overdrive mode sample bit) + - cnt_overdrive_slot (time for overdrive mode data slot) + - cnt_overdrive_presence (time for overdrive mode sample presence) + - cnt_overdrive_reset (time for overdrive mode reset) + +These options should be configured only on very rare cases and the user should read the decoder source code to understand them correctly. +Protocol output format: +TODO. + Annotations: -Link layer annotations show the next events: -- NOTE/WARNING/ERROR - Possible sample rate related timing issues are reported. -- RESET/PRESENCE True/False - The event is marked from the signal negative edge to the end of the reset - high period. It is also reported if there are any devices attached to the - bus. -- BIT 0/1 - The event is marked from the signal negative edge to the end of the data - slot. The value of each received bit is also provided. + +Link layer annotations show the following events: + + - NOTE/WARNING/ERROR + Possible samplerate related timing issues are reported. + - Reset/presence true/false + The event is marked from the signal negative edge to the end of the reset + high period. It's also reported if there are any devices attached to the bus. + - Bit 0/1 + The event is marked from the signal negative edge to the end of the data + slot. The value of each received bit is also provided. TODO: -- check for protocol correctness, if events are timed inside prescribed limits -- maybe add support for interrupts, check if this feature is deprecated +- Check for protocol correctness, if events are timed inside prescribed limits. +- Maybe add support for interrupts, check if this feature is deprecated. ''' -from .onewire_link import * +from .onewire_link import * + diff --git a/decoders/onewire_link/onewire_link.py b/decoders/onewire_link/onewire_link.py index f4b7b30..d6aec2c 100644 --- a/decoders/onewire_link/onewire_link.py +++ b/decoders/onewire_link/onewire_link.py @@ -18,7 +18,7 @@ ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA ## -# 1-Wire link layer protocol decoder +# 1-Wire protocol decoder (link layer) import sigrokdecode as srd @@ -26,7 +26,7 @@ class Decoder(srd.Decoder): api_version = 1 id = 'onewire_link' name = '1-Wire link layer' - longname = '1-Wire serial communication bus' + longname = '1-Wire serial communication bus (link layer)' desc = 'Bidirectional, half-duplex, asynchronous serial bus.' license = 'gplv2+' inputs = ['logic'] @@ -38,200 +38,229 @@ class Decoder(srd.Decoder): {'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_slot' : ['Time (in samplerate periods) for normal mode data slot' , 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_slot' : ['Time (in samplerate periods) for overdrive mode data slot' , 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], + 'overdrive': ['Overdrive', 1], + # Time options (specified in number of samplerate periods): + 'cnt_normal_bit': ['Normal mode sample bit time', 0], + 'cnt_normal_slot': ['Normal mode data slot time', 0], + 'cnt_normal_presence': ['Normal mode sample presence time', 0], + 'cnt_normal_reset': ['Normal mode reset time', 0], + 'cnt_overdrive_bit': ['Overdrive mode sample bit time', 0], + 'cnt_overdrive_slot': ['Overdrive mode data slot time', 0], + 'cnt_overdrive_presence': ['Overdrive mode sample presence time', 0], + 'cnt_overdrive_reset': ['Overdrive mode reset time', 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.state = 'WAIT FOR FALLING EDGE' self.present = 0 - self.bit = 0 + self.bit = 0 self.bit_cnt = 0 self.command = 0 self.overdrive = 0 # Event timing variables - self.fall = 0 - self.rise = 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.out_ann = self.add(srd.OUTPUT_ANN, 'onewire_link') - # check if samplerate is appropriate self.samplerate = metadata['samplerate'] - if (self.options['overdrive']): + + # Check if samplerate is appropriate. + if self.options['overdrive']: self.put(0, 0, self.out_ann, [0, - ['NOTE: Sample rate checks assume overdrive mode.']]) - if (self.samplerate < 2000000): + ['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): + ['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.']]) + ['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): + ['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.']]) + ['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.']]) + ['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']): + # The default 1-Wire time base is 30us. This is used to calculate + # sampling times. + samplerate = float(self.samplerate) + 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_slot']): + self.cnt_normal_bit = int(samplerate * 0.000015) - 1 # 15ns + if self.options['cnt_normal_slot']: self.cnt_normal_slot = self.options['cnt_normal_slot'] else: - self.cnt_normal_slot = int(float(self.samplerate) * 0.000060) - 1 # 60ns - if (self.options['cnt_normal_presence']): + self.cnt_normal_slot = int(samplerate * 0.000060) - 1 # 60ns + 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_presence = int(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_normal_reset = int(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_slot']): + self.cnt_overdrive_bit = int(samplerate * 0.000002) - 1 # 2ns + if self.options['cnt_overdrive_slot']: self.cnt_overdrive_slot = self.options['cnt_overdrive_slot'] else: - self.cnt_overdrive_slot = int(float(self.samplerate) * 0.0000073) - 1 # 6ns+1.3ns - if (self.options['cnt_overdrive_presence']): + self.cnt_overdrive_slot = int(samplerate * 0.0000073) - 1 # 6ns+1.3ns + 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_presence = int(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 + self.cnt_overdrive_reset = int(samplerate * 0.000048) - 1 # 48ns - # organize values into lists - self.cnt_bit = [self.cnt_normal_bit , self.cnt_overdrive_bit ] + # 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)]]) + 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): + if owr == 0: # Save the sample number for the falling edge. self.fall = self.samplenum - # Go to waiting for sample time + # 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 + # 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 - if (self.samplenum - self.fall == self.cnt_slot[self.overdrive]): - if (owr): - self.put(self.fall, self.samplenum, self.out_ann, [0, ['BIT: %01x' % self.bit]]) - self.put(self.fall, self.samplenum, 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 + # 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]: + if owr: + self.put(self.fall, self.samplenum, self.out_ann, + [0, ['BIT: %01x' % self.bit]]) + self.put(self.fall, self.samplenum, 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.bit << self.bit_cnt) + elif self.bit_cnt == 8 and self.command in [0x3c, 0x69]: + self.put(self.fall, self.cnt_bit[self.overdrive], + self.out_ann, + [0, ['ENTER OVERDRIVE MODE']]) + # Increment the bit counter. self.bit_cnt += 1 - # Wait for next slot + # Wait for next slot. self.state = 'WAIT FOR FALLING EDGE' else: - # This seems to be a reset slot, wait for its end + # This seems to be a reset slot, wait for its end. self.state = 'WAIT FOR RISING EDGE' elif self.state == 'WAIT FOR RISING EDGE': # The end of a cycle is a rising edge. - if (owr): - # Check if this was a reset cycle - if (self.samplenum - self.fall > self.cnt_normal_reset): + if owr: + # 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.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['EXIT OVERDRIVE MODE']]) + self.state = 'WAIT FOR PRESENCE DETECT' + # 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 + # 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)): + 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 : + 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]): + # 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 - if (self.samplenum - self.rise == self.cnt_reset[self.overdrive]): - if (owr): - self.put(self.fall, self.samplenum, self.out_ann, [0, ['RESET/PRESENCE: %s' % ('False' if self.present else 'True')]]) - self.put(self.fall, self.samplenum, self.out_proto, ['RESET/PRESENCE', not self.present]) - # Wait for next slot + t = self.samplenum - self.rise + if t == self.cnt_reset[self.overdrive]: + if owr: + self.put(self.fall, self.samplenum, self.out_ann, + [0, ['RESET/PRESENCE: %s' + % ('False' if self.present else 'True')]]) + self.put(self.fall, self.samplenum, self.out_proto, + ['RESET/PRESENCE', not self.present]) + # Wait for next slot. self.state = 'WAIT FOR FALLING EDGE' else: - # This seems to be a reset slot, wait for its end + # This seems to be a reset slot, wait for its end. self.state = 'WAIT FOR RISING EDGE' else: - raise Exception('Invalid state: %d' % self.state) + raise Exception('Invalid state: %s' % self.state)