from .lists import *
import sigrokdecode as srd
+# Concentrate all timing constraints of the IR protocol here in a single
+# location at the top of the source, to raise awareness and to simplify
+# review and adjustment. The tolerance is an arbitrary choice, available
+# literature does not mention any. The inter-frame timeout is not a part
+# of the protocol, but an implementation detail of this sigrok decoder.
+_TIME_TOL = 8 # tolerance, in percent
+_TIME_IDLE = 20.0 # inter-frame timeout, in ms
+_TIME_LC = 13.5 # leader code, in ms
+_TIME_RC = 11.25 # repeat code, in ms
+_TIME_ONE = 2.25 # one data bit, in ms
+_TIME_ZERO = 1.125 # zero data bit, in ms
+_TIME_STOP = 0.562 # stop bit, in ms
+
class SamplerateError(Exception):
pass
)
options = (
{'id': 'polarity', 'desc': 'Polarity', 'default': 'active-low',
- 'values': ('active-low', 'active-high')},
+ 'values': ('auto', 'active-low', 'active-high')},
{'id': 'cd_freq', 'desc': 'Carrier Frequency', 'default': 0},
{'id': 'extended', 'desc': 'Extended NEC Protocol',
'default': 'no', 'values': ('yes', 'no')},
self.samplerate = value
def calc_rate(self):
- self.tolerance = 0.05 # +/-5%
- self.lc = int(self.samplerate * 0.0135) - 1 # 13.5ms
- self.rc = int(self.samplerate * 0.01125) - 1 # 11.25ms
- self.dazero = int(self.samplerate * 0.001125) - 1 # 1.125ms
- self.daone = int(self.samplerate * 0.00225) - 1 # 2.25ms
- self.stop = int(self.samplerate * 0.000652) - 1 # 0.652ms
+ self.tolerance = _TIME_TOL / 100
+ self.lc = int(self.samplerate * _TIME_LC / 1000) - 1
+ self.rc = int(self.samplerate * _TIME_RC / 1000) - 1
+ self.dazero = int(self.samplerate * _TIME_ZERO / 1000) - 1
+ self.daone = int(self.samplerate * _TIME_ONE / 1000) - 1
+ self.stop = int(self.samplerate * _TIME_STOP / 1000) - 1
+ self.idle_to = int(self.samplerate * _TIME_IDLE / 1000) - 1
def compare_with_tolerance(self, measured, base):
return (measured >= base * (1 - self.tolerance)
self.data = []
self.ss_bit = self.ss_start = self.samplenum
return True
+ self.putd(show, want_len)
if check and not valid:
warn_show = bitpack(self.data)
self.putx([Ann.WARN, ['{} error: 0x{:04X}'.format(name, warn_show)]])
- else:
- self.putd(show, want_len)
self.data = []
self.ss_bit = self.ss_start = self.samplenum
return valid
cd_count = int(self.samplerate / self.options['cd_freq']) + 1
prev_ir = None
- active = 0 if self.options['polarity'] == 'active-low' else 1
+ if self.options['polarity'] == 'auto':
+ # Take sample 0 as reference.
+ curr_level, = self.wait({'skip': 0})
+ active = 1 - curr_level
+ else:
+ active = 0 if self.options['polarity'] == 'active-low' else 1
self.is_extended = self.options['extended'] == 'yes'
want_addr_len = 16 if self.is_extended else 8
(self.ir,) = self.wait({Pin.IR: 'e'})
if self.ir != active:
- # Save the non-active edge, then wait for the next edge.
+ # Save the location of the non-active edge (recessive),
+ # then wait for the next edge. Immediately process the
+ # end of the STOP bit which completes an IR frame.
self.ss_other_edge = self.samplenum
- continue
+ if self.state != 'STOP':
+ continue
- b = self.samplenum - self.ss_bit
+ # Reset internal state for long periods of idle level.
+ width = self.samplenum - self.ss_bit
+ if width >= self.idle_to and self.state != 'STOP':
+ self.reset()
# State machine.
if self.state == 'IDLE':
- if self.compare_with_tolerance(b, self.lc):
+ if self.compare_with_tolerance(width, self.lc):
self.putpause('Long')
self.putx([Ann.LEADER_CODE, ['Leader code', 'Leader', 'LC', 'L']])
self.ss_remote = self.ss_start
self.data = []
self.state = 'ADDRESS'
- elif self.compare_with_tolerance(b, self.rc):
+ elif self.compare_with_tolerance(width, self.rc):
self.putpause('Short')
self.putstop(self.samplenum)
self.samplenum += self.stop
self.data = []
self.ss_bit = self.ss_start = self.samplenum
elif self.state == 'ADDRESS':
- self.handle_bit(b)
+ self.handle_bit(width)
if len(self.data) == want_addr_len:
self.data_ok(False, want_addr_len)
self.state = 'COMMAND' if self.is_extended else 'ADDRESS#'
elif self.state == 'ADDRESS#':
- self.handle_bit(b)
+ self.handle_bit(width)
if len(self.data) == 16:
- self.state = 'COMMAND' if self.data_ok(True, 8) else 'IDLE'
+ self.data_ok(True, 8)
+ self.state = 'COMMAND'
elif self.state == 'COMMAND':
- self.handle_bit(b)
+ self.handle_bit(width)
if len(self.data) == 8:
self.data_ok(False, 8)
self.state = 'COMMAND#'
elif self.state == 'COMMAND#':
- self.handle_bit(b)
+ self.handle_bit(width)
if len(self.data) == 16:
- self.state = 'STOP' if self.data_ok(True, 8) else 'IDLE'
+ self.data_ok(True, 8)
+ self.state = 'STOP'
elif self.state == 'STOP':
self.putstop(self.ss_bit)
self.putremote()
projects / libsigrokdecode.git / blobdiff