## 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
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
from .lists import *
+class SamplerateError(Exception):
+ pass
+
class Decoder(srd.Decoder):
- api_version = 2
+ api_version = 3
id = 'ir_nec'
name = 'IR NEC'
longname = 'IR NEC'
options = (
{'id': 'polarity', 'desc': 'Polarity', 'default': 'active-low',
'values': ('active-low', 'active-high')},
+ {'id': 'cd_freq', 'desc': 'Carrier Frequency', 'default': 0},
)
annotations = (
('bit', 'Bit'),
[11, ['%s: %s' % (dev, btn[0]), '%s: %s' % (dev, btn[1]),
'%s' % btn[1]]])
- def __init__(self, **kwargs):
+ def __init__(self):
+ self.reset()
+
+ def reset(self):
self.state = 'IDLE'
self.ss_bit = self.ss_start = self.ss_other_edge = self.ss_remote = 0
- self.data = self.count = self.active = self.old_ir = None
+ self.data = self.count = self.active = None
self.addr = self.cmd = None
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
self.active = 0 if self.options['polarity'] == 'active-low' else 1
- self.old_ir = 1 if self.active == 0 else 0
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value
- self.margin = int(self.samplerate * 0.0001) - 1 # 0.1ms
+ 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
+ def compare_with_tolerance(self, measured, base):
+ return (measured >= base * (1 - self.tolerance)
+ and measured <= base * (1 + self.tolerance))
+
def handle_bit(self, tick):
ret = None
- if tick in range(self.dazero - self.margin, self.dazero + self.margin):
+ if self.compare_with_tolerance(tick, self.dazero):
ret = 0
- elif tick in range(self.daone - self.margin, self.daone + self.margin):
+ elif self.compare_with_tolerance(tick, self.daone):
ret = 1
if ret in (0, 1):
self.putb([0, ['%d' % ret]])
self.ss_bit = self.ss_start = self.samplenum
return ret == 0
- def decode(self, ss, es, data):
- if self.samplerate is None:
- raise Exception("Cannot decode without samplerate.")
- for (self.samplenum, pins) in data:
- self.ir = pins[0]
+ def decode(self):
+ if not self.samplerate:
+ raise SamplerateError('Cannot decode without samplerate.')
+
+ cd_count = None
+ if self.options['cd_freq']:
+ cd_count = int(self.samplerate / self.options['cd_freq']) + 1
+ prev_ir = None
+
+ while True:
+ # Detect changes in the presence of an active input signal.
+ # The decoder can either be fed an already filtered RX signal
+ # or optionally can detect the presence of a carrier. Periods
+ # of inactivity (signal changes slower than the carrier freq,
+ # if specified) pass on the most recently sampled level. This
+ # approach works for filtered and unfiltered input alike, and
+ # only slightly extends the active phase of input signals with
+ # carriers included by one period of the carrier frequency.
+ # IR based communication protocols can cope with this slight
+ # inaccuracy just fine by design. Enabling carrier detection
+ # on already filtered signals will keep the length of their
+ # active period, but will shift their signal changes by one
+ # carrier period before they get passed to decoding logic.
+ if cd_count:
+ (cur_ir,) = self.wait([{0: 'e'}, {'skip': cd_count}])
+ if self.matched[0]:
+ cur_ir = self.active
+ if cur_ir == prev_ir:
+ continue
+ prev_ir = cur_ir
+ self.ir = cur_ir
+ else:
+ (self.ir,) = self.wait({0: 'e'})
- # Wait for an "interesting" edge, but also record the other ones.
- if self.old_ir == self.ir:
- continue
if self.ir != self.active:
+ # Save the non-active edge, then wait for the next edge.
self.ss_other_edge = self.samplenum
- self.old_ir = self.ir
continue
b = self.samplenum - self.ss_bit
# State machine.
if self.state == 'IDLE':
- if b in range(self.lc - self.margin, self.lc + self.margin):
+ if self.compare_with_tolerance(b, self.lc):
self.putpause('Long')
self.putx([5, ['Leader code', 'Leader', 'LC', 'L']])
self.ss_remote = self.ss_start
self.data = self.count = 0
self.state = 'ADDRESS'
- elif b in range(self.rc - self.margin, self.rc + self.margin):
+ elif self.compare_with_tolerance(b, self.rc):
self.putpause('Short')
self.putstop(self.samplenum)
self.samplenum += self.stop
self.putremote()
self.ss_bit = self.ss_start = self.samplenum
self.state = 'IDLE'
-
- self.old_ir = self.ir
-
projects / libsigrokdecode.git / blobdiff