def __init__(self, stream, subdevice, channels, physical=False,
plot=False):
self.stream = stream
self.subdevice = subdevice
self.channels = channels
self.physical = physical
self.plot = plot
if plot:
if _pyplot is None:
raise _matplotlib_import_error
self.figure = _pyplot.figure()
self.axes = self.figure.add_subplot(1, 1, 1)
self.n = 100
self.index = 0
self.tdata = _numpy.arange(self.n)
self.ydata = _numpy.zeros(
(2*self.n, len(channels)), dtype=_numpy.float32)
self.lines = []
for i,channel in enumerate(channels):
self.lines.append(_Line2D(
self.tdata, self.ydata[:self.n,i],
linestyle='', color='red', marker='.'))
self.axes.add_line(self.lines[-1])
self.axes.set_xlim(0, self.n-1)
self.axes.set_ylim(0, max(c.get_maxdata() for c in channels))
_pyplot.draw()
_LOG.debug('data writer initialized')
_LOG.debug('poll: {}'.format(self.subdevice.poll()))
_LOG.debug('get_buffer contents: {}'.format(
self.subdevice.get_buffer_contents()))
def __call__(self, data):
_LOG.debug('new data: {}'.format(data))
d = _numpy.ndarray(shape=(1,data.size), dtype=data.dtype, buffer=data)
if self.plot:
self.ydata[self.index,:] = d
self.ydata[self.index + self.n,:] = d
for i,line in enumerate(self.lines):
line.set_data(
self.tdata,
self.ydata[self.index+1:self.index + self.n+1,i])
_pyplot.draw()
self.index = (self.index + 1) % len(self.tdata)
write_data(
stream=self.stream, channels=self.channels, data=d,
physical=self.physical)
_LOG.debug('poll: {}'.format(self.subdevice.poll()))
_LOG.debug('get_buffer contents: {}'.format(
self.subdevice.get_buffer_contents()))
def read(device, subdevice=None, channels=[0], range=0, aref=0, period=0,
num_scans=2, reader=_utility.Reader, physical=False, plot=False,
stream=_sys.stdout):
"""Read ``num_scans`` samples from each specified channel.
"""
subdevice,channels = open_channels(
device=device, subdevice=subdevice, channels=channels, range=range,
aref=aref)
subdevice.cmd = prepare_command(
subdevice=subdevice, channels=channels, period=period,
num_scans=num_scans)
rc = test_command(subdevice=subdevice)
kwargs = {}
if reader == _utility.CallbackReader:
read_buffer_shape = (len(channels),)
kwargs = {
'callback': DataWriter(
stream=stream, subdevice=subdevice, channels=channels,
physical=physical, plot=plot),
'count': num_scans,
}
else:
read_buffer_shape = (num_scans, len(channels))
read_buffer = _numpy.zeros(read_buffer_shape, dtype=subdevice.get_dtype())
reader = reader(
subdevice=subdevice, buffer=read_buffer, name='Reader', **kwargs)
start = _time.time()
_LOG.info('start time: {}'.format(start))
subdevice.command()
reader.start()
while subdevice.get_flags().running:
_LOG.debug('running...')
_LOG.debug('poll: {}'.format(subdevice.poll()))
_LOG.debug('get_buffer offset: {}'.format(
subdevice.get_buffer_offset()))
_LOG.debug('get_buffer contents: {}'.format(
subdevice.get_buffer_contents()))
_time.sleep(0.5)
_LOG.debug('stopped running. joining reader...')
stop = _time.time()
_LOG.info('stop time: {}'.format(stop))
reader.join()
join = _time.time()
_LOG.info('join time: {}'.format(join))
_LOG.debug('poll: {}'.format(subdevice.poll()))
_LOG.debug('get_buffer offset: {}'.format(
subdevice.get_buffer_offset()))
_LOG.debug('get_buffer contents: {}'.format(
subdevice.get_buffer_contents()))
_LOG.info('stop delay: {}'.format(stop - start))
_LOG.info('join delay: {}'.format(join - stop))
if not isinstance(reader, _utility.CallbackReader):
write_data(
stream=stream, channels=channels, data=read_buffer,
physical=physical)
