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b4332f0f UH |
1 | ## |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2014 Torsten Duwe <duwe@suse.de> | |
9658c710 | 5 | ## Copyright (C) 2014 Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com> |
b4332f0f UH |
6 | ## |
7 | ## This program is free software; you can redistribute it and/or modify | |
8 | ## it under the terms of the GNU General Public License as published by | |
9 | ## the Free Software Foundation; either version 2 of the License, or | |
10 | ## (at your option) any later version. | |
11 | ## | |
12 | ## This program is distributed in the hope that it will be useful, | |
13 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | ## GNU General Public License for more details. | |
16 | ## | |
17 | ## You should have received a copy of the GNU General Public License | |
18 | ## along with this program; if not, write to the Free Software | |
19 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | ## | |
21 | ||
22 | import sigrokdecode as srd | |
23 | ||
24 | class Decoder(srd.Decoder): | |
25 | api_version = 2 | |
26 | id = 'pwm' | |
27 | name = 'PWM' | |
28 | longname = 'Pulse-width modulation' | |
29 | desc = 'Analog level encoded in duty cycle percentage.' | |
30 | license = 'gplv2+' | |
31 | inputs = ['logic'] | |
32 | outputs = ['pwm'] | |
33 | channels = ( | |
9658c710 | 34 | {'id': 'data', 'name': 'Data', 'desc': 'Data line'}, |
b4332f0f UH |
35 | ) |
36 | options = ( | |
9658c710 SB |
37 | {'id': 'polarity', 'desc': 'Polarity', 'default': 'active-high', |
38 | 'values': ('active-low', 'active-high')}, | |
b4332f0f UH |
39 | ) |
40 | annotations = ( | |
9658c710 | 41 | ('duty-cycle', 'Duty cycle'), |
e4227baf MP |
42 | ('period', 'Period'), |
43 | ) | |
44 | annotation_rows = ( | |
45 | ('duty-cycle', 'Duty cycle', (0,)), | |
46 | ('period', 'Period', (1,)), | |
b4332f0f UH |
47 | ) |
48 | binary = ( | |
49 | ('raw', 'RAW file'), | |
50 | ) | |
51 | ||
52 | def __init__(self, **kwargs): | |
9658c710 SB |
53 | self.ss = self.es = None |
54 | self.first_transition = True | |
55 | self.first_samplenum = None | |
56 | self.start_samplenum = None | |
57 | self.end_samplenum = None | |
58 | self.oldpin = None | |
b4332f0f | 59 | self.num_cycles = 0 |
9658c710 | 60 | self.average = 0 |
b4332f0f | 61 | |
e4227baf MP |
62 | def metadata(self, key, value): |
63 | if key == srd.SRD_CONF_SAMPLERATE: | |
64 | self.samplerate = value | |
65 | ||
b4332f0f | 66 | def start(self): |
9658c710 | 67 | self.startedge = 0 if self.options['polarity'] == 'active-low' else 1 |
b4332f0f | 68 | self.out_ann = self.register(srd.OUTPUT_ANN) |
2f370328 | 69 | self.out_binary = self.register(srd.OUTPUT_BINARY) |
9658c710 SB |
70 | self.out_average = \ |
71 | self.register(srd.OUTPUT_META, | |
72 | meta=(float, 'Average', 'PWM base (cycle) frequency')) | |
b4332f0f UH |
73 | |
74 | def putx(self, data): | |
75 | self.put(self.ss, self.es, self.out_ann, data) | |
76 | ||
e4227baf MP |
77 | def putp(self, period_t): |
78 | # Adjust granularity. | |
79 | if period_t == 0 or period_t >= 1: | |
750e122d | 80 | period_s = '%.1f s' % (period_t) |
e4227baf | 81 | elif period_t <= 1e-12: |
750e122d | 82 | period_s = '%.1f fs' % (period_t * 1e15) |
e4227baf | 83 | elif period_t <= 1e-9: |
750e122d | 84 | period_s = '%.1f ps' % (period_t * 1e12) |
e4227baf | 85 | elif period_t <= 1e-6: |
750e122d | 86 | period_s = '%.1f ns' % (period_t * 1e9) |
e4227baf | 87 | elif period_t <= 1e-3: |
750e122d | 88 | period_s = '%.1f μs' % (period_t * 1e6) |
e4227baf | 89 | else: |
750e122d | 90 | period_s = '%.1f ms' % (period_t * 1e3) |
e4227baf MP |
91 | |
92 | self.put(self.ss, self.es, self.out_ann, [1, [period_s]]) | |
93 | ||
b4332f0f | 94 | def putb(self, data): |
2f370328 | 95 | self.put(self.num_cycles, self.num_cycles, self.out_binary, data) |
b4332f0f UH |
96 | |
97 | def decode(self, ss, es, data): | |
9658c710 | 98 | |
b4332f0f UH |
99 | for (self.samplenum, pins) in data: |
100 | # Ignore identical samples early on (for performance reasons). | |
101 | if self.oldpin == pins[0]: | |
102 | continue | |
103 | ||
9658c710 SB |
104 | # Initialize self.oldpins with the first sample value. |
105 | if self.oldpin is None: | |
106 | self.oldpin = pins[0] | |
107 | continue | |
b4332f0f | 108 | |
9658c710 SB |
109 | if self.first_transition: |
110 | # First rising edge | |
111 | if self.oldpin != self.startedge: | |
112 | self.first_samplenum = self.samplenum | |
113 | self.start_samplenum = self.samplenum | |
114 | self.first_transition = False | |
b4332f0f | 115 | else: |
9658c710 SB |
116 | if self.oldpin != self.startedge: |
117 | # Rising edge | |
118 | # We are on a full cycle we can calculate | |
119 | # the period, the duty cycle and its ratio. | |
120 | period = self.samplenum - self.start_samplenum | |
121 | duty = self.end_samplenum - self.start_samplenum | |
122 | ratio = float(duty / period) | |
123 | ||
124 | # This interval starts at this edge. | |
125 | self.ss = self.start_samplenum | |
126 | # Store the new rising edge position and the ending | |
127 | # edge interval. | |
128 | self.start_samplenum = self.es = self.samplenum | |
129 | ||
130 | # Report the duty cycle in percent. | |
131 | percent = float(ratio * 100) | |
e4227baf | 132 | self.putx([0, ['%f%%' % percent]]) |
9658c710 SB |
133 | |
134 | # Report the duty cycle in the binary output. | |
2824e811 | 135 | self.putb([0, bytes([int(ratio * 256)])]) |
9658c710 | 136 | |
e4227baf MP |
137 | # Report the period in units of time. |
138 | period_t = float(period / self.samplerate) | |
139 | self.putp(period_t) | |
140 | ||
9658c710 SB |
141 | # Update and report the new duty cycle average. |
142 | self.num_cycles += 1 | |
143 | self.average += percent | |
144 | self.put(self.first_samplenum, self.es, self.out_average, | |
145 | float(self.average / self.num_cycles)) | |
146 | else: | |
147 | # Falling edge | |
148 | self.end_samplenum = self.ss = self.samplenum | |
b4332f0f | 149 | |
b4332f0f | 150 | self.oldpin = pins[0] |