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1 | ## | |
2 | ## This file is part of the libsigrokdecode project. | |
3 | ## | |
4 | ## Copyright (C) 2011-2014 Uwe Hermann <uwe@hermann-uwe.de> | |
5 | ## | |
6 | ## This program is free software; you can redistribute it and/or modify | |
7 | ## it under the terms of the GNU General Public License as published by | |
8 | ## the Free Software Foundation; either version 2 of the License, or | |
9 | ## (at your option) any later version. | |
10 | ## | |
11 | ## This program is distributed in the hope that it will be useful, | |
12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ## GNU General Public License for more details. | |
15 | ## | |
16 | ## You should have received a copy of the GNU General Public License | |
17 | ## along with this program; if not, see <http://www.gnu.org/licenses/>. | |
18 | ## | |
19 | ||
20 | import sigrokdecode as srd | |
21 | from common.srdhelper import bitpack | |
22 | from math import floor, ceil | |
23 | ||
24 | ''' | |
25 | OUTPUT_PYTHON format: | |
26 | ||
27 | Packet: | |
28 | [<ptype>, <rxtx>, <pdata>] | |
29 | ||
30 | This is the list of <ptype>s and their respective <pdata> values: | |
31 | - 'STARTBIT': The data is the (integer) value of the start bit (0/1). | |
32 | - 'DATA': This is always a tuple containing two items: | |
33 | - 1st item: the (integer) value of the UART data. Valid values | |
34 | range from 0 to 511 (as the data can be up to 9 bits in size). | |
35 | - 2nd item: the list of individual data bits and their ss/es numbers. | |
36 | - 'PARITYBIT': The data is the (integer) value of the parity bit (0/1). | |
37 | - 'STOPBIT': The data is the (integer) value of the stop bit (0 or 1). | |
38 | - 'INVALID STARTBIT': The data is the (integer) value of the start bit (0/1). | |
39 | - 'INVALID STOPBIT': The data is the (integer) value of the stop bit (0/1). | |
40 | - 'PARITY ERROR': The data is a tuple with two entries. The first one is | |
41 | the expected parity value, the second is the actual parity value. | |
42 | - TODO: Frame error? | |
43 | ||
44 | The <rxtx> field is 0 for RX packets, 1 for TX packets. | |
45 | ''' | |
46 | ||
47 | # Used for differentiating between the two data directions. | |
48 | RX = 0 | |
49 | TX = 1 | |
50 | ||
51 | # Given a parity type to check (odd, even, zero, one), the value of the | |
52 | # parity bit, the value of the data, and the length of the data (5-9 bits, | |
53 | # usually 8 bits) return True if the parity is correct, False otherwise. | |
54 | # 'none' is _not_ allowed as value for 'parity_type'. | |
55 | def parity_ok(parity_type, parity_bit, data, num_data_bits): | |
56 | ||
57 | # Handle easy cases first (parity bit is always 1 or 0). | |
58 | if parity_type == 'zero': | |
59 | return parity_bit == 0 | |
60 | elif parity_type == 'one': | |
61 | return parity_bit == 1 | |
62 | ||
63 | # Count number of 1 (high) bits in the data (and the parity bit itself!). | |
64 | ones = bin(data).count('1') + parity_bit | |
65 | ||
66 | # Check for odd/even parity. | |
67 | if parity_type == 'odd': | |
68 | return (ones % 2) == 1 | |
69 | elif parity_type == 'even': | |
70 | return (ones % 2) == 0 | |
71 | ||
72 | class SamplerateError(Exception): | |
73 | pass | |
74 | ||
75 | class ChannelError(Exception): | |
76 | pass | |
77 | ||
78 | class Decoder(srd.Decoder): | |
79 | api_version = 3 | |
80 | id = 'uart' | |
81 | name = 'UART' | |
82 | longname = 'Universal Asynchronous Receiver/Transmitter' | |
83 | desc = 'Asynchronous, serial bus.' | |
84 | license = 'gplv2+' | |
85 | inputs = ['logic'] | |
86 | outputs = ['uart'] | |
87 | optional_channels = ( | |
88 | # Allow specifying only one of the signals, e.g. if only one data | |
89 | # direction exists (or is relevant). | |
90 | {'id': 'rx', 'name': 'RX', 'desc': 'UART receive line'}, | |
91 | {'id': 'tx', 'name': 'TX', 'desc': 'UART transmit line'}, | |
92 | ) | |
93 | options = ( | |
94 | {'id': 'baudrate', 'desc': 'Baud rate', 'default': 115200}, | |
95 | {'id': 'num_data_bits', 'desc': 'Data bits', 'default': 8, | |
96 | 'values': (5, 6, 7, 8, 9)}, | |
97 | {'id': 'parity_type', 'desc': 'Parity type', 'default': 'none', | |
98 | 'values': ('none', 'odd', 'even', 'zero', 'one')}, | |
99 | {'id': 'parity_check', 'desc': 'Check parity?', 'default': 'yes', | |
100 | 'values': ('yes', 'no')}, | |
101 | {'id': 'num_stop_bits', 'desc': 'Stop bits', 'default': 1.0, | |
102 | 'values': (0.0, 0.5, 1.0, 1.5)}, | |
103 | {'id': 'bit_order', 'desc': 'Bit order', 'default': 'lsb-first', | |
104 | 'values': ('lsb-first', 'msb-first')}, | |
105 | {'id': 'format', 'desc': 'Data format', 'default': 'hex', | |
106 | 'values': ('ascii', 'dec', 'hex', 'oct', 'bin')}, | |
107 | {'id': 'invert_rx', 'desc': 'Invert RX?', 'default': 'no', | |
108 | 'values': ('yes', 'no')}, | |
109 | {'id': 'invert_tx', 'desc': 'Invert TX?', 'default': 'no', | |
110 | 'values': ('yes', 'no')}, | |
111 | ) | |
112 | annotations = ( | |
113 | ('rx-data', 'RX data'), | |
114 | ('tx-data', 'TX data'), | |
115 | ('rx-start', 'RX start bits'), | |
116 | ('tx-start', 'TX start bits'), | |
117 | ('rx-parity-ok', 'RX parity OK bits'), | |
118 | ('tx-parity-ok', 'TX parity OK bits'), | |
119 | ('rx-parity-err', 'RX parity error bits'), | |
120 | ('tx-parity-err', 'TX parity error bits'), | |
121 | ('rx-stop', 'RX stop bits'), | |
122 | ('tx-stop', 'TX stop bits'), | |
123 | ('rx-warnings', 'RX warnings'), | |
124 | ('tx-warnings', 'TX warnings'), | |
125 | ('rx-data-bits', 'RX data bits'), | |
126 | ('tx-data-bits', 'TX data bits'), | |
127 | ) | |
128 | annotation_rows = ( | |
129 | ('rx-data', 'RX', (0, 2, 4, 6, 8)), | |
130 | ('rx-data-bits', 'RX bits', (12,)), | |
131 | ('rx-warnings', 'RX warnings', (10,)), | |
132 | ('tx-data', 'TX', (1, 3, 5, 7, 9)), | |
133 | ('tx-data-bits', 'TX bits', (13,)), | |
134 | ('tx-warnings', 'TX warnings', (11,)), | |
135 | ) | |
136 | binary = ( | |
137 | ('rx', 'RX dump'), | |
138 | ('tx', 'TX dump'), | |
139 | ('rxtx', 'RX/TX dump'), | |
140 | ) | |
141 | idle_state = ['WAIT FOR START BIT', 'WAIT FOR START BIT'] | |
142 | ||
143 | def putx(self, rxtx, data): | |
144 | s, halfbit = self.startsample[rxtx], self.bit_width / 2.0 | |
145 | self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_ann, data) | |
146 | ||
147 | def putpx(self, rxtx, data): | |
148 | s, halfbit = self.startsample[rxtx], self.bit_width / 2.0 | |
149 | self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_python, data) | |
150 | ||
151 | def putg(self, data): | |
152 | s, halfbit = self.samplenum, self.bit_width / 2.0 | |
153 | self.put(s - floor(halfbit), s + ceil(halfbit), self.out_ann, data) | |
154 | ||
155 | def putp(self, data): | |
156 | s, halfbit = self.samplenum, self.bit_width / 2.0 | |
157 | self.put(s - floor(halfbit), s + ceil(halfbit), self.out_python, data) | |
158 | ||
159 | def putbin(self, rxtx, data): | |
160 | s, halfbit = self.startsample[rxtx], self.bit_width / 2.0 | |
161 | self.put(s - floor(halfbit), self.samplenum + ceil(halfbit), self.out_binary, data) | |
162 | ||
163 | def __init__(self): | |
164 | self.reset() | |
165 | ||
166 | def reset(self): | |
167 | self.samplerate = None | |
168 | self.samplenum = 0 | |
169 | self.frame_start = [-1, -1] | |
170 | self.startbit = [-1, -1] | |
171 | self.cur_data_bit = [0, 0] | |
172 | self.datavalue = [0, 0] | |
173 | self.paritybit = [-1, -1] | |
174 | self.stopbit1 = [-1, -1] | |
175 | self.startsample = [-1, -1] | |
176 | self.state = ['WAIT FOR START BIT', 'WAIT FOR START BIT'] | |
177 | self.databits = [[], []] | |
178 | ||
179 | def start(self): | |
180 | self.out_python = self.register(srd.OUTPUT_PYTHON) | |
181 | self.out_binary = self.register(srd.OUTPUT_BINARY) | |
182 | self.out_ann = self.register(srd.OUTPUT_ANN) | |
183 | self.bw = (self.options['num_data_bits'] + 7) // 8 | |
184 | ||
185 | def metadata(self, key, value): | |
186 | if key == srd.SRD_CONF_SAMPLERATE: | |
187 | self.samplerate = value | |
188 | # The width of one UART bit in number of samples. | |
189 | self.bit_width = float(self.samplerate) / float(self.options['baudrate']) | |
190 | ||
191 | def get_sample_point(self, rxtx, bitnum): | |
192 | # Determine absolute sample number of a bit slot's sample point. | |
193 | # bitpos is the samplenumber which is in the middle of the | |
194 | # specified UART bit (0 = start bit, 1..x = data, x+1 = parity bit | |
195 | # (if used) or the first stop bit, and so on). | |
196 | # The samples within bit are 0, 1, ..., (bit_width - 1), therefore | |
197 | # index of the middle sample within bit window is (bit_width - 1) / 2. | |
198 | bitpos = self.frame_start[rxtx] + (self.bit_width - 1) / 2.0 | |
199 | bitpos += bitnum * self.bit_width | |
200 | return bitpos | |
201 | ||
202 | def wait_for_start_bit(self, rxtx, signal): | |
203 | # Save the sample number where the start bit begins. | |
204 | self.frame_start[rxtx] = self.samplenum | |
205 | ||
206 | self.state[rxtx] = 'GET START BIT' | |
207 | ||
208 | def get_start_bit(self, rxtx, signal): | |
209 | self.startbit[rxtx] = signal | |
210 | ||
211 | # The startbit must be 0. If not, we report an error and wait | |
212 | # for the next start bit (assuming this one was spurious). | |
213 | if self.startbit[rxtx] != 0: | |
214 | self.putp(['INVALID STARTBIT', rxtx, self.startbit[rxtx]]) | |
215 | self.putg([rxtx + 10, ['Frame error', 'Frame err', 'FE']]) | |
216 | self.state[rxtx] = 'WAIT FOR START BIT' | |
217 | return | |
218 | ||
219 | self.cur_data_bit[rxtx] = 0 | |
220 | self.datavalue[rxtx] = 0 | |
221 | self.startsample[rxtx] = -1 | |
222 | ||
223 | self.putp(['STARTBIT', rxtx, self.startbit[rxtx]]) | |
224 | self.putg([rxtx + 2, ['Start bit', 'Start', 'S']]) | |
225 | ||
226 | self.state[rxtx] = 'GET DATA BITS' | |
227 | ||
228 | def get_data_bits(self, rxtx, signal): | |
229 | # Save the sample number of the middle of the first data bit. | |
230 | if self.startsample[rxtx] == -1: | |
231 | self.startsample[rxtx] = self.samplenum | |
232 | ||
233 | self.putg([rxtx + 12, ['%d' % signal]]) | |
234 | ||
235 | # Store individual data bits and their start/end samplenumbers. | |
236 | s, halfbit = self.samplenum, int(self.bit_width / 2) | |
237 | self.databits[rxtx].append([signal, s - halfbit, s + halfbit]) | |
238 | ||
239 | # Return here, unless we already received all data bits. | |
240 | self.cur_data_bit[rxtx] += 1 | |
241 | if self.cur_data_bit[rxtx] < self.options['num_data_bits']: | |
242 | return | |
243 | ||
244 | # Convert accumulated data bits to a data value. | |
245 | bits = [b[0] for b in self.databits[rxtx]] | |
246 | if self.options['bit_order'] == 'msb-first': | |
247 | bits.reverse() | |
248 | self.datavalue[rxtx] = bitpack(bits) | |
249 | self.putpx(rxtx, ['DATA', rxtx, | |
250 | (self.datavalue[rxtx], self.databits[rxtx])]) | |
251 | ||
252 | b = self.datavalue[rxtx] | |
253 | formatted = self.format_value(b) | |
254 | if formatted is not None: | |
255 | self.putx(rxtx, [rxtx, [formatted]]) | |
256 | ||
257 | bdata = b.to_bytes(self.bw, byteorder='big') | |
258 | self.putbin(rxtx, [rxtx, bdata]) | |
259 | self.putbin(rxtx, [2, bdata]) | |
260 | ||
261 | self.databits[rxtx] = [] | |
262 | ||
263 | # Advance to either reception of the parity bit, or reception of | |
264 | # the STOP bits if parity is not applicable. | |
265 | self.state[rxtx] = 'GET PARITY BIT' | |
266 | if self.options['parity_type'] == 'none': | |
267 | self.state[rxtx] = 'GET STOP BITS' | |
268 | ||
269 | def format_value(self, v): | |
270 | # Format value 'v' according to configured options. | |
271 | # Reflects the user selected kind of representation, as well as | |
272 | # the number of data bits in the UART frames. | |
273 | ||
274 | fmt, bits = self.options['format'], self.options['num_data_bits'] | |
275 | ||
276 | # Assume "is printable" for values from 32 to including 126, | |
277 | # below 32 is "control" and thus not printable, above 127 is | |
278 | # "not ASCII" in its strict sense, 127 (DEL) is not printable, | |
279 | # fall back to hex representation for non-printables. | |
280 | if fmt == 'ascii': | |
281 | if v in range(32, 126 + 1): | |
282 | return chr(v) | |
283 | hexfmt = "[{:02X}]" if bits <= 8 else "[{:03X}]" | |
284 | return hexfmt.format(v) | |
285 | ||
286 | # Mere number to text conversion without prefix and padding | |
287 | # for the "decimal" output format. | |
288 | if fmt == 'dec': | |
289 | return "{:d}".format(v) | |
290 | ||
291 | # Padding with leading zeroes for hex/oct/bin formats, but | |
292 | # without a prefix for density -- since the format is user | |
293 | # specified, there is no ambiguity. | |
294 | if fmt == 'hex': | |
295 | digits = (bits + 4 - 1) // 4 | |
296 | fmtchar = "X" | |
297 | elif fmt == 'oct': | |
298 | digits = (bits + 3 - 1) // 3 | |
299 | fmtchar = "o" | |
300 | elif fmt == 'bin': | |
301 | digits = bits | |
302 | fmtchar = "b" | |
303 | else: | |
304 | fmtchar = None | |
305 | if fmtchar is not None: | |
306 | fmt = "{{:0{:d}{:s}}}".format(digits, fmtchar) | |
307 | return fmt.format(v) | |
308 | ||
309 | return None | |
310 | ||
311 | def get_parity_bit(self, rxtx, signal): | |
312 | self.paritybit[rxtx] = signal | |
313 | ||
314 | if parity_ok(self.options['parity_type'], self.paritybit[rxtx], | |
315 | self.datavalue[rxtx], self.options['num_data_bits']): | |
316 | self.putp(['PARITYBIT', rxtx, self.paritybit[rxtx]]) | |
317 | self.putg([rxtx + 4, ['Parity bit', 'Parity', 'P']]) | |
318 | else: | |
319 | # TODO: Return expected/actual parity values. | |
320 | self.putp(['PARITY ERROR', rxtx, (0, 1)]) # FIXME: Dummy tuple... | |
321 | self.putg([rxtx + 6, ['Parity error', 'Parity err', 'PE']]) | |
322 | ||
323 | self.state[rxtx] = 'GET STOP BITS' | |
324 | ||
325 | # TODO: Currently only supports 1 stop bit. | |
326 | def get_stop_bits(self, rxtx, signal): | |
327 | self.stopbit1[rxtx] = signal | |
328 | ||
329 | # Stop bits must be 1. If not, we report an error. | |
330 | if self.stopbit1[rxtx] != 1: | |
331 | self.putp(['INVALID STOPBIT', rxtx, self.stopbit1[rxtx]]) | |
332 | self.putg([rxtx + 10, ['Frame error', 'Frame err', 'FE']]) | |
333 | # TODO: Abort? Ignore the frame? Other? | |
334 | ||
335 | self.putp(['STOPBIT', rxtx, self.stopbit1[rxtx]]) | |
336 | self.putg([rxtx + 4, ['Stop bit', 'Stop', 'T']]) | |
337 | ||
338 | self.state[rxtx] = 'WAIT FOR START BIT' | |
339 | ||
340 | def get_wait_cond(self, rxtx, inv): | |
341 | # Return condititions that are suitable for Decoder.wait(). Those | |
342 | # conditions either match the falling edge of the START bit, or | |
343 | # the sample point of the next bit time. | |
344 | state = self.state[rxtx] | |
345 | if state == 'WAIT FOR START BIT': | |
346 | return {rxtx: 'r' if inv else 'f'} | |
347 | if state == 'GET START BIT': | |
348 | bitnum = 0 | |
349 | elif state == 'GET DATA BITS': | |
350 | bitnum = 1 + self.cur_data_bit[rxtx] | |
351 | elif state == 'GET PARITY BIT': | |
352 | bitnum = 1 + self.options['num_data_bits'] | |
353 | elif state == 'GET STOP BITS': | |
354 | bitnum = 1 + self.options['num_data_bits'] | |
355 | bitnum += 0 if self.options['parity_type'] == 'none' else 1 | |
356 | want_num = ceil(self.get_sample_point(rxtx, bitnum)) | |
357 | return {'skip': want_num - self.samplenum} | |
358 | ||
359 | def inspect_sample(self, rxtx, signal, inv): | |
360 | # Inspect a sample returned by .wait() for the specified UART line. | |
361 | if inv: | |
362 | signal = not signal | |
363 | ||
364 | state = self.state[rxtx] | |
365 | if state == 'WAIT FOR START BIT': | |
366 | self.wait_for_start_bit(rxtx, signal) | |
367 | elif state == 'GET START BIT': | |
368 | self.get_start_bit(rxtx, signal) | |
369 | elif state == 'GET DATA BITS': | |
370 | self.get_data_bits(rxtx, signal) | |
371 | elif state == 'GET PARITY BIT': | |
372 | self.get_parity_bit(rxtx, signal) | |
373 | elif state == 'GET STOP BITS': | |
374 | self.get_stop_bits(rxtx, signal) | |
375 | ||
376 | def decode(self): | |
377 | if not self.samplerate: | |
378 | raise SamplerateError('Cannot decode without samplerate.') | |
379 | ||
380 | has_pin = [self.has_channel(ch) for ch in (RX, TX)] | |
381 | if has_pin == [False, False]: | |
382 | raise ChannelError('Either TX or RX (or both) pins required.') | |
383 | ||
384 | opt = self.options | |
385 | inv = [opt['invert_rx'] == 'yes', opt['invert_tx'] == 'yes'] | |
386 | cond_idx = [None] * len(has_pin) | |
387 | ||
388 | while True: | |
389 | conds = [] | |
390 | if has_pin[RX]: | |
391 | cond_idx[RX] = len(conds) | |
392 | conds.append(self.get_wait_cond(RX, inv[RX])) | |
393 | if has_pin[TX]: | |
394 | cond_idx[TX] = len(conds) | |
395 | conds.append(self.get_wait_cond(TX, inv[TX])) | |
396 | (rx, tx) = self.wait(conds) | |
397 | if cond_idx[RX] is not None and self.matched[cond_idx[RX]]: | |
398 | self.inspect_sample(RX, rx, inv[RX]) | |
399 | if cond_idx[TX] is not None and self.matched[cond_idx[TX]]: | |
400 | self.inspect_sample(TX, tx, inv[TX]) |