pyafm/digital_port.py

   1 # Copyright
   2
   3 from pycomedi.channel import DigitalChannel as _DigitalChannel
   4 import pypiezo.base as _base
   5
   6
   7 class DigitalPort (object):
   8     """A digital input/output port (i.e. cluster of channels).
   9
  10     >>> from pyafm.config import DigitalPortConfig
  11
  12     >>> devices = []
  13
  14     >>> config = DigitalPortConfig()
  15     >>> config['channels'] = [1, 2, 3, 4]
  16     >>> config['name'] = 'test port'
  17
  18     >>> port = DigitalPort(config=config, devices=devices)
  19     >>> port.write_bitfield(13)
  20     >>> port.write([1, 0, 1, 0])
  21     >>> port.write_bitfield(0)
  22
  23     >>> for device in devices:
  24     ...     device.close()
  25     """
  26     def __init__(self, config, devices=None):
  27         self.config = config
  28         self.subdevice = None
  29         self.load_from_config(devices=devices)
  30
  31     def load_from_config(self, devices):
  32         c = self.config  # reduce verbosity
  33         if self.subdevice is None:
  34             device = _base.load_device(filename=c['device'], devices=devices)
  35             if c['subdevice'] < 0:
  36                 self.subdevice = device.find_subdevice_by_type(
  37                     c['subdevice-type'])
  38             else:
  39                 self.subdevice = device.subdevice(index=c['subdevice'])
  40             self.channels = []
  41             self.write_mask = 0
  42             for index in c['channels']:
  43                 channel = self.subdevice.channel(
  44                     index=index, factory=_DigitalChannel)
  45                 channel.dio_config(c['direction'])
  46                 self.write_mask |= 1 << index
  47                 self.channels.append(channel)
  48         self.name = c['name']
  49
  50     def setup_config(self):
  51         self.config['device'] = self.subdevice.device.filename
  52         self.config['subdevice'] = self.subdevice.index
  53         self.config['channels'] = [c.index for c in self.channels]
  54         if self.channels:
  55             self.config['direction'] = self.channels[0].dio_get_config()
  56
  57     def write(self, values):
  58         value = 0
  59         for channel,val in zip(self.channels, values):
  60             value &= val * (1 << channel.index)
  61         self.write_bitfield(value)
  62
  63     def write_bitfield(self, value):
  64         self.subdevice.dio_bitfield(bits=value, write_mask=self.write_mask)