--- /dev/null
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2014 Johannes Roemer <jroemer@physik.uni-wuerzburg.de>
+##
+## 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
+##
+
+import sigrokdecode as srd
+
+# Define valid timing values (in microseconds).
+timing = {
+ 'START LOW' : {'min': 750, 'max': 25000},
+ 'START HIGH' : {'min': 10, 'max': 10000},
+ 'RESPONSE LOW' : {'min': 70, 'max': 90},
+ 'RESPONSE HIGH' : {'min': 70, 'max': 90},
+ 'BIT LOW' : {'min': 45, 'max': 90},
+ 'BIT 0 HIGH' : {'min': 20, 'max': 35},
+ 'BIT 1 HIGH' : {'min': 65, 'max': 80},
+}
+
+class SamplerateError(Exception):
+ pass
+
+class Decoder(srd.Decoder):
+ api_version = 2
+ id = 'am230x'
+ name = 'AM230x'
+ longname = 'AM230x humidity and temperature sensors'
+ desc = 'Proprietary single wire communication bus.'
+ license = 'gplv2+'
+ inputs = ['logic']
+ outputs = ['am230x']
+ channels = (
+ {'id': 'sda', 'name': 'SDA', 'desc': 'Single wire serial data line'},
+ )
+ options = (
+ {'id': 'dht11', 'desc': 'DHT11 compatibility mode',
+ 'default': 'no', 'values': ('no', 'yes')},
+ )
+ annotations = (
+ ('start', 'Start'),
+ ('response', 'Response'),
+ ('bit', 'Bit'),
+ ('end', 'End'),
+ ('byte', 'Byte'),
+ ('humidity', 'Relative humidity in percent'),
+ ('temperature', 'Temperature in degrees Celsius'),
+ ('checksum', 'Checksum'),
+ )
+ annotation_rows = (
+ ('bits', 'Bits', (0, 1, 2, 3)),
+ ('bytes', 'Bytes', (4,)),
+ ('results', 'Results', (5, 6, 7)),
+ )
+
+ def putfs(self, data):
+ self.put(self.fall, self.samplenum, self.out_ann, data)
+
+ def putb(self, data):
+ self.put(self.bytepos[-1], self.samplenum, self.out_ann, data)
+
+ def putv(self, data):
+ self.put(self.bytepos[-2], self.samplenum, self.out_ann, data)
+
+ def reset(self):
+ self.state = 'WAIT FOR START LOW'
+ self.samplenum = 0
+ self.fall = 0
+ self.rise = 0
+ self.bits = []
+ self.bytepos = []
+
+ def is_valid(self, name):
+ dt = 0
+ if name.endswith('LOW'):
+ dt = self.samplenum - self.fall
+ elif name.endswith('HIGH'):
+ dt = self.samplenum - self.rise
+ if dt >= self.cnt[name]['min'] and dt <= self.cnt[name]['max']:
+ return True
+ return False
+
+ def bits2num(self, bitlist):
+ number = 0
+ for i in range(0, len(bitlist)):
+ number += bitlist[-1-i] * 2**i
+ return number
+
+ def calculate_humidity(self, bitlist):
+ h = 0
+ if self.options['dht11'] == 'yes':
+ h = self.bits2num(bitlist[0:8])
+ else:
+ h = self.bits2num(bitlist) / 10
+ return h
+
+ def calculate_temperature(self, bitlist):
+ t = 0
+ if self.options['dht11'] == 'yes':
+ t = self.bits2num(bitlist[0:8])
+ else:
+ t = self.bits2num(bitlist[1:]) / 10
+ if bitlist[0] == 1:
+ t = -t
+ return t
+
+ def calculate_checksum(self, bitlist):
+ checksum = 0
+ for i in range(8, len(bitlist)+1, 8):
+ checksum += self.bits2num(bitlist[i-8:i])
+ return checksum % 256
+
+ def __init__(self, **kwargs):
+ self.samplerate = None
+ self.reset()
+
+ def start(self):
+ self.out_ann = self.register(srd.OUTPUT_ANN)
+
+ def metadata(self, key, value):
+ if key != srd.SRD_CONF_SAMPLERATE:
+ return
+ self.samplerate = value
+ # Convert microseconds to sample counts.
+ self.cnt = {}
+ for e in timing:
+ self.cnt[e] = {}
+ for t in timing[e]:
+ self.cnt[e][t] = timing[e][t] * self.samplerate / 1000000
+
+ def decode(self, ss, es, data):
+ if not self.samplerate:
+ raise SamplerateError('Cannot decode without samplerate.')
+ for (self.samplenum, (sda,)) in data:
+ # State machine.
+ if self.state == 'WAIT FOR START LOW':
+ if sda != 0:
+ continue
+ self.fall = self.samplenum
+ self.state = 'WAIT FOR START HIGH'
+ elif self.state == 'WAIT FOR START HIGH':
+ if sda != 1:
+ continue
+ if self.is_valid('START LOW'):
+ self.rise = self.samplenum
+ self.state = 'WAIT FOR RESPONSE LOW'
+ else:
+ self.reset()
+ elif self.state == 'WAIT FOR RESPONSE LOW':
+ if sda != 0:
+ continue
+ if self.is_valid('START HIGH'):
+ self.putfs([0, ['Start', 'S']])
+ self.fall = self.samplenum
+ self.state = 'WAIT FOR RESPONSE HIGH'
+ else:
+ self.reset()
+ elif self.state == 'WAIT FOR RESPONSE HIGH':
+ if sda != 1:
+ continue
+ if self.is_valid('RESPONSE LOW'):
+ self.rise = self.samplenum
+ self.state = 'WAIT FOR FIRST BIT'
+ else:
+ self.reset()
+ elif self.state == 'WAIT FOR FIRST BIT':
+ if sda != 0:
+ continue
+ if self.is_valid('RESPONSE HIGH'):
+ self.putfs([1, ['Response', 'R']])
+ self.fall = self.samplenum
+ self.bytepos.append(self.samplenum)
+ self.state = 'WAIT FOR BIT HIGH'
+ else:
+ self.reset_variables()
+ elif self.state == 'WAIT FOR BIT HIGH':
+ if sda != 1:
+ continue
+ if self.is_valid('BIT LOW'):
+ self.rise = self.samplenum
+ self.state = 'WAIT FOR BIT LOW'
+ else:
+ self.reset()
+ elif self.state == 'WAIT FOR BIT LOW':
+ if sda != 0:
+ continue
+ if self.is_valid('BIT 0 HIGH'):
+ bit = 0
+ elif self.is_valid('BIT 1 HIGH'):
+ bit = 1
+ else:
+ self.reset()
+ continue
+ self.bits.append(bit)
+ self.putfs([2, ['Bit: %d' % bit, '%d' % bit]])
+ self.fall = self.samplenum
+ self.state = 'WAIT FOR BIT HIGH'
+ if len(self.bits) % 8 == 0:
+ byte = self.bits2num(self.bits[-8:])
+ self.putb([4, ['Byte: %#04x' % byte, '%#04x' % byte]])
+ if len(self.bits) == 16:
+ h = self.calculate_humidity(self.bits[-16:])
+ self.putv([5, ['Humidity: %.1f %%' % h, 'RH = %.1f %%' % h]])
+ elif len(self.bits) == 32:
+ t = self.calculate_temperature(self.bits[-16:])
+ self.putv([6, ['Temperature: %.1f °C' % t, 'T = %.1f °C' % t]])
+ elif len(self.bits) == 40:
+ parity = self.bits2num(self.bits[-8:])
+ if parity == self.calculate_checksum(self.bits[0:32]):
+ self.putb([7, ['Checksum: OK', 'OK']])
+ else:
+ self.putb([7, ['Checksum: not OK', 'NOK']])
+ self.state = 'WAIT FOR END'
+ self.bytepos.append(self.samplenum)
+ elif self.state == 'WAIT FOR END':
+ if sda != 1:
+ continue
+ self.putfs([3, ['End', 'E']])
+ self.reset()
projects / libsigrokdecode.git / commitdiff