[libsigrokdecode.git] / decoders / onewire_link / onewire_link.py

##
## 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_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],
    }
    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_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_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_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_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

        # 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
                    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
                        self.bit_cnt += 1
                        # Wait for next slot
                        self.state = 'WAIT FOR FALLING EDGE'
                    else:
                        # 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):
                        # 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.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"
                    # 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
                    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
                        self.state = 'WAIT FOR FALLING EDGE'
                    else:
                        # 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)
Commit	Line	Data
9cfb16e8 IJ	1	##
	2	## This file is part of the sigrok project.
	3	##
	4	## Copyright (C) 2012 Iztok Jeras <iztok.jeras@gmail.com>
	5	##
	6	## This program is free software; you can redistribute it and/or modify
	7	## it under the terms of the GNU General Public License as published by
	8	## the Free Software Foundation; either version 2 of the License, or
	9	## (at your option) any later version.
	10	##
	11	## This program is distributed in the hope that it will be useful,
	12	## but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	## GNU General Public License for more details.
	15	##
	16	## You should have received a copy of the GNU General Public License
	17	## along with this program; if not, write to the Free Software
	18	## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	##
	20
	21	# 1-Wire link layer protocol decoder
	22
	23	import sigrokdecode as srd
	24
	25	class Decoder(srd.Decoder):
	26	api_version = 1
	27	id = 'onewire_link'
	28	name = '1-Wire link layer'
	29	longname = '1-Wire serial communication bus'
	30	desc = 'Bidirectional, half-duplex, asynchronous serial bus.'
	31	license = 'gplv2+'
	32	inputs = ['logic']
	33	outputs = ['onewire_link']
	34	probes = [
	35	{'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
	36	]
	37	optional_probes = [
	38	{'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
	39	]
	40	options = {
	41	'overdrive' : ['Overdrive', 1],
	42	'cnt_normal_bit' : ['Time (in samplerate periods) for normal mode sample bit' , 0],
671cc300	43	'cnt_normal_slot' : ['Time (in samplerate periods) for normal mode data slot' , 0],
9cfb16e8 IJ	44	'cnt_normal_presence' : ['Time (in samplerate periods) for normal mode sample presence', 0],
	45	'cnt_normal_reset' : ['Time (in samplerate periods) for normal mode reset' , 0],
	46	'cnt_overdrive_bit' : ['Time (in samplerate periods) for overdrive mode sample bit' , 0],
671cc300	47	'cnt_overdrive_slot' : ['Time (in samplerate periods) for overdrive mode data slot' , 0],
9cfb16e8 IJ	48	'cnt_overdrive_presence': ['Time (in samplerate periods) for overdrive mode sample presence', 0],
	49	'cnt_overdrive_reset' : ['Time (in samplerate periods) for overdrive mode reset' , 0],
	50	}
	51	annotations = [
	52	['Link', 'Link layer events (reset, presence, bit slots)'],
	53	]
	54
	55	def __init__(self, **kwargs):
	56	# Common variables
	57	self.samplenum = 0
	58	# Link layer variables
	59	self.state = 'WAIT FOR FALLING EDGE'
	60	self.present = 0
	61	self.bit = 0
99f5f3b5 IJ	62	self.bit_cnt = 0
99f5f3b5 IJ	63	self.command = 0
9cfb16e8	64	self.overdrive = 0
9cfb16e8 IJ	65	# Event timing variables
	66	self.fall = 0
	67	self.rise = 0
	68
	69	def start(self, metadata):
	70	self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire_link')
	71	self.out_ann = self.add(srd.OUTPUT_ANN , 'onewire_link')
	72
	73	# check if samplerate is appropriate
	74	self.samplerate = metadata['samplerate']
	75	if (self.options['overdrive']):
	76	self.put(0, 0, self.out_ann, [0,
	77	['NOTE: Sample rate checks assume overdrive mode.']])
	78	if (self.samplerate < 2000000):
	79	self.put(0, 0, self.out_ann, [0,
	80	['ERROR: Sampling rate is too low must be above 2MHz for proper overdrive mode decoding.']])
	81	elif (self.samplerate < 5000000):
	82	self.put(0, 0, self.out_ann, [0,
	83	['WARNING: Sampling rate is suggested to be above 5MHz for proper overdrive mode decoding.']])
	84	else:
	85	self.put(0, 0, self.out_ann, [0,
	86	['NOTE: Sample rate checks assume normal mode only.']])
	87	if (self.samplerate < 400000):
	88	self.put(0, 0, self.out_ann, [0,
	89	['ERROR: Sampling rate is too low must be above 400kHz for proper normal mode decoding.']])
	90	elif (self.samplerate < 1000000):
	91	self.put(0, 0, self.out_ann, [0,
	92	['WARNING: Sampling rate is suggested to be above 1MHz for proper normal mode decoding.']])
	93
	94	# The default 1-Wire time base is 30us, this is used to calculate sampling times.
	95	if (self.options['cnt_normal_bit']):
	96	self.cnt_normal_bit = self.options['cnt_normal_bit']
	97	else:
	98	self.cnt_normal_bit = int(float(self.samplerate) * 0.000015) - 1 # 15ns
671cc300 IJ	99	if (self.options['cnt_normal_slot']):
	100	self.cnt_normal_slot = self.options['cnt_normal_slot']
	101	else:
	102	self.cnt_normal_slot = int(float(self.samplerate) * 0.000060) - 1 # 60ns
9cfb16e8 IJ	103	if (self.options['cnt_normal_presence']):
	104	self.cnt_normal_presence = self.options['cnt_normal_presence']
	105	else:
	106	self.cnt_normal_presence = int(float(self.samplerate) * 0.000075) - 1 # 75ns
	107	if (self.options['cnt_normal_reset']):
	108	self.cnt_normal_reset = self.options['cnt_normal_reset']
	109	else:
	110	self.cnt_normal_reset = int(float(self.samplerate) * 0.000480) - 1 # 480ns
	111	if (self.options['cnt_overdrive_bit']):
	112	self.cnt_overdrive_bit = self.options['cnt_overdrive_bit']
	113	else:
	114	self.cnt_overdrive_bit = int(float(self.samplerate) * 0.000002) - 1 # 2ns
671cc300 IJ	115	if (self.options['cnt_overdrive_slot']):
	116	self.cnt_overdrive_slot = self.options['cnt_overdrive_slot']
	117	else:
	118	self.cnt_overdrive_slot = int(float(self.samplerate) * 0.0000073) - 1 # 6ns+1.3ns
9cfb16e8 IJ	119	if (self.options['cnt_overdrive_presence']):
	120	self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
	121	else:
	122	self.cnt_overdrive_presence = int(float(self.samplerate) * 0.000010) - 1 # 10ns
	123	if (self.options['cnt_overdrive_reset']):
	124	self.cnt_overdrive_reset = self.options['cnt_overdrive_reset']
	125	else:
	126	self.cnt_overdrive_reset = int(float(self.samplerate) * 0.000048) - 1 # 48ns
	127
9cfb16e8 IJ	128	# organize values into lists
	129	self.cnt_bit = [self.cnt_normal_bit , self.cnt_overdrive_bit ]
	130	self.cnt_presence = [self.cnt_normal_presence, self.cnt_overdrive_presence]
	131	self.cnt_reset = [self.cnt_normal_reset , self.cnt_overdrive_reset ]
	132	self.cnt_slot = [self.cnt_normal_slot , self.cnt_overdrive_slot ]
	133
	134	# Check if sample times are in the allowed range
	135	time_min = float(self.cnt_normal_bit ) / self.samplerate
	136	time_max = float(self.cnt_normal_bit+1) / self.samplerate
	137	if ( (time_min < 0.000005) or (time_max > 0.000015) ) :
	138	self.put(0, 0, self.out_ann, [0,
	139	['WARNING: The normal mode data sample time interval (%2.1fus-%2.1fus) should be inside (5.0us, 15.0us).'
	140	% (time_min1000000, time_max1000000)]])
	141	time_min = float(self.cnt_normal_presence ) / self.samplerate
	142	time_max = float(self.cnt_normal_presence+1) / self.samplerate
	143	if ( (time_min < 0.0000681) or (time_max > 0.000075) ) :
	144	self.put(0, 0, self.out_ann, [0,
	145	['WARNING: The normal mode presence sample time interval (%2.1fus-%2.1fus) should be inside (68.1us, 75.0us).'
	146	% (time_min1000000, time_max1000000)]])
	147	time_min = float(self.cnt_overdrive_bit ) / self.samplerate
	148	time_max = float(self.cnt_overdrive_bit+1) / self.samplerate
	149	if ( (time_min < 0.000001) or (time_max > 0.000002) ) :
	150	self.put(0, 0, self.out_ann, [0,
	151	['WARNING: The overdrive mode data sample time interval (%2.1fus-%2.1fus) should be inside (1.0us, 2.0us).'
	152	% (time_min1000000, time_max1000000)]])
	153	time_min = float(self.cnt_overdrive_presence ) / self.samplerate
	154	time_max = float(self.cnt_overdrive_presence+1) / self.samplerate
	155	if ( (time_min < 0.0000073) or (time_max > 0.000010) ) :
	156	self.put(0, 0, self.out_ann, [0,
	157	['WARNING: The overdrive mode presence sample time interval (%2.1fus-%2.1fus) should be inside (7.3us, 10.0us).'
	158	% (time_min1000000, time_max1000000)]])
	159
	160	def report(self):
	161	pass
	162
	163	def decode(self, ss, es, data):
	164	for (self.samplenum, (owr, pwr)) in data:
	165
	166	# State machine.
	167	if self.state == 'WAIT FOR FALLING EDGE':
	168	# The start of a cycle is a falling edge.
	169	if (owr == 0):
	170	# Save the sample number for the falling edge.
	171	self.fall = self.samplenum
	172	# Go to waiting for sample time
	173	self.state = 'WAIT FOR DATA SAMPLE'
	174	elif self.state == 'WAIT FOR DATA SAMPLE':
	175	# Sample data bit
	176	if (self.samplenum - self.fall == self.cnt_bit[self.overdrive]):
671cc300 IJ	177	self.bit = owr
	178	self.state = 'WAIT FOR DATA SLOT END'
	179	elif self.state == 'WAIT FOR DATA SLOT END':
	180	# A data slot ends in a recovery period, otherwise, this is probably a reset
	181	if (self.samplenum - self.fall == self.cnt_slot[self.overdrive]):
	182	if (owr):
	183	self.put(self.fall, self.samplenum, self.out_ann, [0, ['BIT: %01x' % self.bit]])
	184	self.put(self.fall, self.samplenum, self.out_proto, ['BIT', self.bit])
	185	# Checking the first command to see if overdrive mode should be entered
	186	if (self.bit_cnt <= 8):
	187	self.command = self.command \| (self.bit << self.bit_cnt)
	188	elif (self.bit_cnt == 8):
	189	if (self.command in [0x3c, 0x69]):
	190	self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['ENTER OVERDRIVE MODE']])
	191	# Incrementing the bit counter
	192	self.bit_cnt += 1
	193	# Wait for next slot
	194	self.state = 'WAIT FOR FALLING EDGE'
	195	else:
	196	# This seems to be a reset slot, wait for its end
	197	self.state = 'WAIT FOR RISING EDGE'
9cfb16e8 IJ	198	elif self.state == 'WAIT FOR RISING EDGE':
9cfb16e8 IJ	199	# The end of a cycle is a rising edge.
671cc300	200	if (owr):
9cfb16e8 IJ	201	# Check if this was a reset cycle
	202	if (self.samplenum - self.fall > self.cnt_normal_reset):
	203	# Save the sample number for the falling edge.
	204	self.rise = self.samplenum
	205	self.state = "WAIT FOR PRESENCE DETECT"
9cfb16e8	206	# Exit overdrive mode
e540618c IJ	207	if (self.overdrive):
	208	self.put(self.fall, self.cnt_bit[self.overdrive], self.out_ann, [0, ['EXIT OVERDRIVE MODE']])
	209	self.overdrive = 0
	210	# Clear command bit counter and data register
99f5f3b5	211	self.bit_cnt = 0
9cfb16e8 IJ	212	self.command = 0
	213	elif ((self.samplenum - self.fall > self.cnt_overdrive_reset) and (self.overdrive)):
	214	# Save the sample number for the falling edge.
	215	self.rise = self.samplenum
	216	self.state = "WAIT FOR PRESENCE DETECT"
9cfb16e8 IJ	217	# Otherwise this is assumed to be a data bit.
	218	else :
	219	self.state = "WAIT FOR FALLING EDGE"
	220	elif self.state == 'WAIT FOR PRESENCE DETECT':
	221	# Sample presence status
	222	if (self.samplenum - self.rise == self.cnt_presence[self.overdrive]):
671cc300 IJ	223	self.present = owr
	224	self.state = 'WAIT FOR RESET SLOT END'
	225	elif self.state == 'WAIT FOR RESET SLOT END':
	226	# A reset slot ends in a long recovery period
	227	if (self.samplenum - self.rise == self.cnt_reset[self.overdrive]):
	228	if (owr):
	229	self.put(self.fall, self.samplenum, self.out_ann, [0, ['RESET/PRESENCE: %s' % ('False' if self.present else 'True')]])
	230	self.put(self.fall, self.samplenum, self.out_proto, ['RESET/PRESENCE', not self.present])
	231	# Wait for next slot
	232	self.state = 'WAIT FOR FALLING EDGE'
	233	else:
	234	# This seems to be a reset slot, wait for its end
	235	self.state = 'WAIT FOR RISING EDGE'
9cfb16e8 IJ	236	else:
9cfb16e8 IJ	237	raise Exception('Invalid state: %d' % self.state)