diff options
Diffstat (limited to 'decoders')
| -rw-r--r-- | decoders/sdq/pd.py | 42 |
1 files changed, 17 insertions, 25 deletions
diff --git a/decoders/sdq/pd.py b/decoders/sdq/pd.py index d8df89f..c65faa8 100644 --- a/decoders/sdq/pd.py +++ b/decoders/sdq/pd.py @@ -64,7 +64,6 @@ class Decoder(srd.Decoder): def reset(self): self.samplerate = None - self.state = 'INIT' self.startsample = 0 self.bits = [] self.bytepos = 0 @@ -98,30 +97,23 @@ class Decoder(srd.Decoder): self.bit_width = float(self.samplerate) / float(self.options['bitrate']) self.half_bit_width = self.bit_width / 2.0 # BREAK if the line is low for longer than this. - self.break_threshold = self.bit_width * 1.2 + break_threshold = self.bit_width * 1.2 + # Wait until the line is high before inspecting input data. + sdq, = self.wait({0: 'h'}) while True: - if self.state == 'INIT': - sdq, = self.wait({0: 'h'}) # Wait until the line is high before starting - self.state = 'DATA' - - elif self.state == 'DATA': - sdq, = self.wait({0: 'f'}) # Falling edge - - self.startsample = self.samplenum - if self.bytepos == 0: - self.bytepos = self.samplenum - - sdq, = self.wait({0: 'r'}) # Rising edge - - delta = self.samplenum - self.startsample - if delta > self.break_threshold: - self.state = 'BREAK' - elif delta > self.half_bit_width: - self.handle_bit(0) - else: - self.handle_bit(1) - - elif self.state == 'BREAK': + # Get the length of a low pulse (falling to rising edge). + sdq, = self.wait({0: 'f'}) + self.startsample = self.samplenum + if self.bytepos == 0: + self.bytepos = self.samplenum + sdq, = self.wait({0: 'r'}) + + # Check for 0 or 1 data bits, or the BREAK symbol. + delta = self.samplenum - self.startsample + if delta > break_threshold: self.handle_break() - self.state = 'DATA' + elif delta > self.half_bit_width: + self.handle_bit(0) + else: + self.handle_bit(1) |