projects / sigrok-meter.git / blame
| Commit | Line | Data |
|---|---|---|
| 48723bbb JS |
1 | ## |
| 2 | ## This file is part of the sigrok-meter project. | |
| 3 | ## | |
| 4 | ## Copyright (C) 2013 Uwe Hermann <uwe@hermann-uwe.de> | |
| 5 | ## Copyright (C) 2014 Jens Steinhauser <jens.steinhauser@gmail.com> | |
| 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 qtcompat | |
| 23 | import sigrok.core as sr | |
| 24 | ||
| 25 | QtCore = qtcompat.QtCore | |
| 26 | QtGui = qtcompat.QtGui | |
| 27 | ||
| 28 | class SamplingThread(QtCore.QObject): | |
| 29 | '''A class that handles the reception of sigrok packets in the background.''' | |
| 30 | ||
| 31 | class Worker(QtCore.QObject): | |
| 32 | '''Helper class that does the actual work in another thread.''' | |
| 33 | ||
| 34 | '''Signal emitted when new data arrived.''' | |
| 35 | measured = QtCore.Signal(object, object, object) | |
| 36 | ||
| 37 | '''Signal emmited in case of an error.''' | |
| 38 | error = QtCore.Signal(str) | |
| 39 | ||
| 40 | def __init__(self, context, drivers): | |
| 41 | super(self.__class__, self).__init__() | |
| 42 | ||
| 43 | self.context = context | |
| 44 | self.drivers = drivers | |
| 45 | ||
| 46 | self.sampling = False | |
| 47 | ||
| 48 | @QtCore.Slot() | |
| 49 | def start_sampling(self): | |
| 50 | devices = [] | |
| 51 | for name, options in self.drivers: | |
| 52 | try: | |
| 53 | dr = self.context.drivers[name] | |
| 54 | devices.append(dr.scan(**options)[0]) | |
| 55 | except: | |
| 56 | self.error.emit( | |
| 57 | 'Unable to get device for driver "{}".'.format(name)) | |
| 58 | return | |
| 59 | ||
| 60 | self.session = self.context.create_session() | |
| 61 | for dev in devices: | |
| 62 | self.session.add_device(dev) | |
| 63 | dev.open() | |
| 64 | self.session.add_datafeed_callback(self.callback) | |
| 65 | self.session.start() | |
| 66 | self.sampling = True | |
| 67 | self.session.run() | |
| 68 | ||
| 69 | # If sampling is 'True' here, it means that 'stop_sampling()' was | |
| 70 | # not called, therefore 'session.run()' ended too early, indicating | |
| 71 | # an error. | |
| 72 | if self.sampling: | |
| 73 | self.error.emit('An error occured during the acquisition.') | |
| 74 | ||
| 75 | def stop_sampling(self): | |
| 76 | if self.sampling: | |
| 77 | self.sampling = False | |
| 78 | self.session.stop() | |
| 79 | ||
| 80 | def callback(self, device, packet): | |
| 81 | if not sr: | |
| 82 | # In rare cases it can happen that the callback fires while | |
| 83 | # the interpreter is shutting down. Then the sigrok module | |
| 84 | # is already set to 'None'. | |
| 85 | return | |
| 86 | ||
| 87 | if packet.type != sr.PacketType.ANALOG: | |
| 88 | return | |
| 89 | ||
| 90 | if not len(packet.payload.channels): | |
| 91 | return | |
| 92 | ||
| 93 | # TODO: find a device with multiple channels in one packet | |
| 94 | channel = packet.payload.channels[0] | |
| 95 | ||
| 96 | # the most recent value | |
| 97 | value = packet.payload.data[0][-1] | |
| 98 | ||
| 99 | self.measured.emit(device, channel, | |
| 100 | (value, packet.payload.unit, packet.payload.mq_flags)) | |
| 101 | ||
| 102 | # signal used to start the worker across threads | |
| 103 | _start_signal = QtCore.Signal() | |
| 104 | ||
| 105 | def __init__(self, context, drivers): | |
| 106 | super(self.__class__, self).__init__() | |
| 107 | ||
| 108 | self.worker = self.Worker(context, drivers) | |
| 109 | self.thread = QtCore.QThread() | |
| 110 | self.worker.moveToThread(self.thread) | |
| 111 | ||
| 112 | self._start_signal.connect(self.worker.start_sampling) | |
| 113 | ||
| 114 | # expose the signals of the worker | |
| 115 | self.measured = self.worker.measured | |
| 116 | self.error = self.worker.error | |
| 117 | ||
| 118 | self.thread.start() | |
| 119 | ||
| 120 | def start(self): | |
| 121 | '''Starts sampling''' | |
| 122 | self._start_signal.emit() | |
| 123 | ||
| 124 | def stop(self): | |
| 125 | '''Stops sampling and the background thread.''' | |
| 126 | self.worker.stop_sampling() | |
| 127 | self.thread.quit() | |
| 128 | self.thread.wait() |