## ## This file is part of the libsigrokdecode project. ## ## Copyright (C) 2017 Christoph Rackwitz ## ## 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, see . ## import math import sigrokdecode as srd from collections import deque from common.srdhelper import bitpack, bitunpack def gray_encode(plain): return plain & (plain >> 1) def gray_decode(gray): temp = gray temp ^= (temp >> 8) temp ^= (temp >> 4) temp ^= (temp >> 2) temp ^= (temp >> 1) return temp def prefix_fmt(value, emin=None): sgn = (value > 0) - (value < 0) value = abs(value) p = math.log10(value) if value else 0 value = sgn * math.floor(value * 10**int(3 - p)) * 10**-int(3 - p) e = p // 3 * 3 if emin is not None and e < emin: e = emin value *= 10**-e p -= e decimals = 2 - int(p) prefixes = {-9: 'n', -6: 'µ', -3: 'm', 0: '', 3: 'k', 6: 'M', 9: 'G'} return '{0:.{1}f} {2}'.format(value, decimals, prefixes[e]) class ChannelMapError(Exception): pass class Value: def __init__(self, onchange): self.onchange = onchange self.timestamp = None self.value = None def get(self): return self.value def set(self, timestamp, newval): if newval != self.value: if self.value is not None: self.onchange(self.timestamp, self.value, timestamp, newval) self.value = newval self.timestamp = timestamp elif False: if self.value is not None: self.onchange(self.timestamp, self.value, timestamp, newval) MAX_CHANNELS = 8 # 10 channels causes some weird problems... class Decoder(srd.Decoder): api_version = 3 id = 'graycode' name = 'Gray code' longname = 'Gray code and rotary encoder' desc = 'Accumulate rotary encoder increments, provide timing statistics.' license = 'gplv2+' inputs = ['logic'] outputs = ['graycode'] optional_channels = tuple( {'id': 'd{}'.format(i), 'name': 'D{}'.format(i), 'desc': 'Data line {}'.format(i)} for i in range(MAX_CHANNELS) ) options = ( {'id': 'edges', 'desc': 'Edges per rotation', 'default': 0}, {'id': 'avg_period', 'desc': 'Averaging period', 'default': 10}, ) annotations = ( ('phase', 'Phase'), ('increment', 'Increment'), ('count', 'Count'), ('turns', 'Turns'), ('interval', 'Interval'), ('average', 'Average'), ('rpm', 'Rate'), ) annotation_rows = tuple((u, v, (i,)) for i, (u, v) in enumerate(annotations)) def __init__(self): self.reset() def reset(self): self.num_channels = 0 self.samplerate = None self.last_n = deque() self.phase = Value(self.on_phase) self.increment = Value(self.on_increment) self.count = Value(self.on_count) self.turns = Value(self.on_turns) def on_phase(self, told, vold, tnew, vnew): self.put(told, tnew, self.out_ann, [0, ['{}'.format(vold)]]) def on_increment(self, told, vold, tnew, vnew): if vold == 0: message = '0' elif abs(vold) == self.ENCODER_STEPS // 2: message = '±π' else: message = '{:+d}'.format(vold) self.put(told, tnew, self.out_ann, [1, [message]]) def on_count(self, told, vold, tnew, vnew): self.put(told, tnew, self.out_ann, [2, ['{}'.format(vold)]]) def on_turns(self, told, vold, tnew, vnew): self.put(told, tnew, self.out_ann, [3, ['{:+d}'.format(vold)]]) def metadata(self, key, value): if key == srd.SRD_CONF_SAMPLERATE: self.samplerate = value def start(self): self.out_ann = self.register(srd.OUTPUT_ANN) def decode(self): chmask = [self.has_channel(i) for i in range(MAX_CHANNELS)] self.num_channels = sum(chmask) if chmask != [i < self.num_channels for i in range(MAX_CHANNELS)]: raise ChannelMapError('Assigned channels need to be contiguous') self.ENCODER_STEPS = 1 << self.num_channels startbits = self.wait() curtime = self.samplenum self.turns.set(self.samplenum, 0) self.count.set(self.samplenum, 0) self.phase.set(self.samplenum, gray_decode(bitpack(startbits[:self.num_channels]))) while True: prevtime = curtime bits = self.wait([{i: 'e'} for i in range(self.num_channels)]) curtime = self.samplenum oldcount = self.count.get() oldphase = self.phase.get() newphase = gray_decode(bitpack(bits[:self.num_channels])) self.phase.set(self.samplenum, newphase) phasedelta_raw = (newphase - oldphase + (self.ENCODER_STEPS // 2 - 1)) % self.ENCODER_STEPS - (self.ENCODER_STEPS // 2 - 1) phasedelta = phasedelta_raw self.increment.set(self.samplenum, phasedelta) if abs(phasedelta) == self.ENCODER_STEPS // 2: phasedelta = 0 self.count.set(self.samplenum, self.count.get() + phasedelta) if self.options['edges']: self.turns.set(self.samplenum, self.count.get() // self.options['edges']) if self.samplerate: period = (curtime - prevtime) / self.samplerate freq = abs(phasedelta_raw) / period self.put(prevtime, curtime, self.out_ann, [4, [ '{}s, {}Hz'.format(prefix_fmt(period), prefix_fmt(freq))]]) if self.options['avg_period']: self.last_n.append((abs(phasedelta_raw), period)) if len(self.last_n) > self.options['avg_period']: self.last_n.popleft() avg_period = sum(v for u, v in self.last_n) / (sum(u for u, v in self.last_n) or 1) self.put(prevtime, curtime, self.out_ann, [5, [ '{}s, {}Hz'.format(prefix_fmt(avg_period), prefix_fmt(1 / avg_period))]]) if self.options['edges']: self.put(prevtime, curtime, self.out_ann, [6, ['{}rpm'.format(prefix_fmt(60 * freq / self.options['edges'], emin=0))]])