/usr/lib/python3/dist-packages/pyvisa/resources/gpib.py is in python3-pyvisa 1.8-2.
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"""
pyvisa.resources.gpib
~~~~~~~~~~~~~~~~~~~~~
High level wrapper for GPIB resources.
This file is part of PyVISA.
:copyright: 2014 by PyVISA Authors, see AUTHORS for more details.
:license: MIT, see LICENSE for more details.
"""
from __future__ import division, unicode_literals, print_function, absolute_import
import time
from .. import constants
from .resource import Resource
from .messagebased import MessageBasedResource, ControlRenMixin
class _GPIBMixin(ControlRenMixin):
"""Common attributes and methods of GPIB Instr and Interface.
"""
def send_command(self, data):
"""Write GPIB command bytes on the bus.
Corresponds to viGpibCommand function of the VISA library.
:param data: data tor write.
:type data: bytes
:return: Number of written bytes, return value of the library call.
:rtype: int, VISAStatus
"""
return self.visalib.gpib_command(self.session, data)
def control_atn(self, mode):
"""Specifies the state of the ATN line and the local active controller state.
Corresponds to viGpibControlATN function of the VISA library.
:param mode: Specifies the state of the ATN line and optionally the local active controller state.
(Constants.GPIB_ATN*)
:return: return value of the library call.
:rtype: VISAStatus
"""
return self.visalib.gpib_control_atn(self.session, mode)
def pass_control(self, primary_address, secondary_address):
"""Tell the GPIB device at the specified address to become controller in charge (CIC).
Corresponds to viGpibPassControl function of the VISA library.
:param primary_address: Primary address of the GPIB device to which you want to pass control.
:param secondary_address: Secondary address of the targeted GPIB device.
If the targeted device does not have a secondary address,
this parameter should contain the value Constants.NO_SEC_ADDR.
:return: return value of the library call.
:rtype: VISAStatus
"""
return self.visalib.gpib_pass_control(self.session, primary_address, secondary_address)
def send_ifc(self):
"""Pulse the interface clear line (IFC) for at least 100 microseconds.
Corresponds to viGpibSendIFC function of the VISA library.
:return: return value of the library call.
:rtype: VISAStatus
"""
return self.visalib.gpib_send_ifc(self.session)
@Resource.register(constants.InterfaceType.gpib, 'INSTR')
class GPIBInstrument(_GPIBMixin, MessageBasedResource):
"""Communicates with to devices of type GPIB::<primary address>[::INSTR]
More complex resource names can be specified with the following grammar:
GPIB[board]::primary address[::secondary address][::INSTR]
Do not instantiate directly, use :meth:`pyvisa.highlevel.ResourceManager.open_resource`.
"""
def wait_for_srq(self, timeout=25000):
"""Wait for a serial request (SRQ) coming from the instrument.
Note that this method is not ended when *another* instrument signals an
SRQ, only *this* instrument.
:param timeout: the maximum waiting time in milliseconds.
Defaul: 25000 (milliseconds).
None means waiting forever if necessary.
"""
self.enable_event(constants.VI_EVENT_SERVICE_REQ, constants.VI_QUEUE)
if timeout and not(0 <= timeout <= 4294967295):
raise ValueError("timeout value is invalid")
starting_time = time.clock()
while True:
if timeout is None:
adjusted_timeout = constants.VI_TMO_INFINITE
else:
adjusted_timeout = int((starting_time + timeout/1e3 - time.clock())*1e3)
if adjusted_timeout < 0:
adjusted_timeout = 0
self.wait_on_event(constants.VI_EVENT_SERVICE_REQ, adjusted_timeout)
if self.stb & 0x40:
break
self.discard_events(constants.VI_EVENT_SERVICE_REQ, constants.VI_QUEUE)
@Resource.register(constants.InterfaceType.gpib, 'INTFC')
class GPIBInterface(_GPIBMixin, Resource):
"""Communicates with to devices of type GPIB::INTFC
More complex resource names can be specified with the following grammar:
GPIB[board]::INTFC
Do not instantiate directly, use :meth:`pyvisa.highlevel.ResourceManager.open_resource`.
"""
def group_execute_trigger(self, *resources):
for resource in resources:
if not isinstance(resource, GPIBInstrument):
raise ValueError('%r is not a GPIBInstrument', resource)
# TODO: check that all resources are in the same board.
if not self.is_controller_in_charge:
self.send_ifc()
command = [0x40, 0x20+31, ] # broadcast TAD#0 and "UNL" (don't listen) to all devices
for resource in resources:
# tell device GPIB::11 to listen
command.append(0x20 + resource.primary_address)
# send GET ('group execute trigger')
command.append(0x08)
return self.send_command(bytes(command))
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