diff options
| -rw-r--r-- | decoders/pwm/pd.py | 89 |
1 files changed, 56 insertions, 33 deletions
diff --git a/decoders/pwm/pd.py b/decoders/pwm/pd.py index 999b496..148b34b 100644 --- a/decoders/pwm/pd.py +++ b/decoders/pwm/pd.py @@ -2,6 +2,7 @@ ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2014 Torsten Duwe <duwe@suse.de> +## Copyright (C) 2014 Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.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 @@ -30,68 +31,90 @@ class Decoder(srd.Decoder): inputs = ['logic'] outputs = ['pwm'] channels = ( - {'id': 'pwm', 'name': 'PWM in', 'desc': 'Modulation pulses'}, + {'id': 'data', 'name': 'Data', 'desc': 'Data line'}, ) options = ( - {'id': 'new_cycle_edge', 'desc': 'New cycle on which edge', - 'default': 'rising', 'values': ('rising', 'falling')}, + {'id': 'polarity', 'desc': 'Polarity', 'default': 'active-high', + 'values': ('active-low', 'active-high')}, ) annotations = ( - ('value', 'PWM value'), + ('duty-cycle', 'Duty cycle'), ) binary = ( ('raw', 'RAW file'), ) def __init__(self, **kwargs): - self.ss = self.es = -1 - self.high = 1 - self.low = 1 - self.lastedge = 0 - self.oldpin = 0 - self.startedge = 0 + self.ss = self.es = None + self.first_transition = True + self.first_samplenum = None + self.start_samplenum = None + self.end_samplenum = None + self.oldpin = None self.num_cycles = 0 + self.average = 0 def start(self): - self.out_python = self.register(srd.OUTPUT_PYTHON) + self.startedge = 0 if self.options['polarity'] == 'active-low' else 1 self.out_ann = self.register(srd.OUTPUT_ANN) self.out_bin = self.register(srd.OUTPUT_BINARY) - self.out_freq = self.register(srd.OUTPUT_META, - meta=(int, 'Frequency', 'PWM base (cycle) frequency')) - self.startedge = 0 - if self.options['new_cycle_edge'] == 'falling': - self.startedge = 1 + self.out_average = \ + self.register(srd.OUTPUT_META, + meta=(float, 'Average', 'PWM base (cycle) frequency')) def putx(self, data): self.put(self.ss, self.es, self.out_ann, data) - def putp(self, data): - self.put(self.ss, self.es, self.out_python, data) - def putb(self, data): self.put(self.num_cycles, self.num_cycles, self.out_bin, data) def decode(self, ss, es, data): + for (self.samplenum, pins) in data: # Ignore identical samples early on (for performance reasons). if self.oldpin == pins[0]: continue - if self.oldpin == 0: # Rising edge. - self.low = self.samplenum - self.lastedge - else: - self.high = self.samplenum - self.lastedge + # Initialize self.oldpins with the first sample value. + if self.oldpin is None: + self.oldpin = pins[0] + continue - if self.oldpin == self.startedge: - self.es = self.samplenum # This interval ends at this edge. - if self.ss >= 0: # Have we completed a hi-lo sequence? - self.putx([0, ["%d%%" % ((100 * self.high) // (self.high + self.low))]]) - self.putb((0, bytes([(256 * self.high) // (self.high + self.low)]))) - self.num_cycles += 1 + if self.first_transition: + # First rising edge + if self.oldpin != self.startedge: + self.first_samplenum = self.samplenum + self.start_samplenum = self.samplenum + self.first_transition = False else: - # Mid-interval. - # This interval started at the previous edge. - self.ss = self.lastedge + if self.oldpin != self.startedge: + # Rising edge + # We are on a full cycle we can calculate + # the period, the duty cycle and its ratio. + period = self.samplenum - self.start_samplenum + duty = self.end_samplenum - self.start_samplenum + ratio = float(duty / period) + + # This interval starts at this edge. + self.ss = self.start_samplenum + # Store the new rising edge position and the ending + # edge interval. + self.start_samplenum = self.es = self.samplenum + + # Report the duty cycle in percent. + percent = float(ratio * 100) + self.putx([0, ["%f%%" % percent]]) + + # Report the duty cycle in the binary output. + self.putb((0, bytes([int(ratio * 256)]))) + + # Update and report the new duty cycle average. + self.num_cycles += 1 + self.average += percent + self.put(self.first_samplenum, self.es, self.out_average, + float(self.average / self.num_cycles)) + else: + # Falling edge + self.end_samplenum = self.ss = self.samplenum - self.lastedge = self.samplenum self.oldpin = pins[0] |