/usr/lib/python2.7/dist-packages/pyvisa-py/serial.py is in python-pyvisa-py 0.2-1.
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"""
pyvisa-py.serial
~~~~~~~~~~~~~~~~
Serial Session implementation using PySerial.
:copyright: 2014 by PyVISA-py Authors, see AUTHORS for more details.
:license: MIT, see LICENSE for more details.
"""
from __future__ import division, unicode_literals, print_function, absolute_import
from pyvisa import constants, attributes, logger
from .sessions import Session, UnknownAttribute
from . import common
try:
import serial
from serial import Serial
from serial.tools.list_ports import comports
except ImportError as e:
Session.register_unavailable(constants.InterfaceType.asrl, 'INSTR',
'Please install PySerial to use this resource type.\n%s' % e)
raise
def to_state(boolean_input):
"""Convert a boolean input into a LineState value
"""
if boolean_input:
return constants.LineState.asserted
return constants.LineState.unasserted
StatusCode = constants.StatusCode
SUCCESS = StatusCode.success
SerialTermination = constants.SerialTermination
@Session.register(constants.InterfaceType.asrl, 'INSTR')
class SerialSession(Session):
"""A serial Session that uses PySerial to do the low level communication.
"""
@staticmethod
def list_resources():
return ['ASRL%s::INSTR' % port[0] for port in comports()]
@classmethod
def get_low_level_info(cls):
try:
ver = serial.VERSION
except AttributeError:
ver = 'N/A'
return 'via PySerial (%s)' % ver
def after_parsing(self):
if 'mock' in self.parsed:
cls = self.parsed.mock
else:
cls = Serial
self.interface = cls(port=self.parsed.board, timeout=2000, writeTimeout=2000)
for name in 'ASRL_END_IN,ASRL_END_OUT,SEND_END_EN,TERMCHAR,' \
'TERMCHAR_EN,SUPPRESS_END_EN'.split(','):
attribute = getattr(constants, 'VI_ATTR_' + name)
self.attrs[attribute] = attributes.AttributesByID[attribute].default
@property
def timeout(self):
value = self.interface.timeout
if value is None:
return constants.VI_TMO_INFINITE
elif value == 0:
return constants.VI_TMO_IMMEDIATE
else:
return int(value * 1000)
@timeout.setter
def timeout(self, value):
if value == constants.VI_TMO_INFINITE:
value = None
elif value == constants.VI_TMO_IMMEDIATE:
value = 0
else:
value = value / 1000.
self.interface.timeout = value
self.interface.writeTimeout = value
def close(self):
self.interface.close()
def read(self, count):
"""Reads data from device or interface synchronously.
Corresponds to viRead function of the VISA library.
:param count: Number of bytes to be read.
:return: data read, return value of the library call.
:rtype: bytes, constants.StatusCode
"""
end_in, _ = self.get_attribute(constants.VI_ATTR_ASRL_END_IN)
suppress_end_en, _ = self.get_attribute(constants.VI_ATTR_SUPPRESS_END_EN)
reader = lambda: self.interface.read(1)
if end_in == SerialTermination.none:
checker = lambda current: False
elif end_in == SerialTermination.last_bit:
mask = 2 ** self.interface.bytesize
checker = lambda current: bool(common.last_int(current) & mask)
elif end_in == SerialTermination.termination_char:
end_char, _ = self.get_attribute(constants.VI_ATTR_TERMCHAR)
checker = lambda current: common.last_int(current) == end_char
else:
raise ValueError('Unknown value for VI_ATTR_ASRL_END_IN: %s' % end_in)
return self._read(reader, count, checker, suppress_end_en, None, False,
serial.SerialTimeoutException)
def write(self, data):
"""Writes data to device or interface synchronously.
Corresponds to viWrite function of the VISA library.
:param data: data to be written.
:type data: bytes
:return: Number of bytes actually transferred, return value of the library call.
:rtype: int, VISAStatus
"""
logger.debug('Serial.write %r' % data)
# TODO: How to deal with VI_ATTR_TERMCHAR_EN
end_out, _ = self.get_attribute(constants.VI_ATTR_ASRL_END_OUT)
send_end, _ = self.get_attribute(constants.VI_ATTR_SEND_END_EN)
try:
# We need to wrap data in common.iter_bytes to Provide Python 2 and 3 compatibility
if end_out in (SerialTermination.none, SerialTermination.termination_break):
data = common.iter_bytes(data)
elif end_out == SerialTermination.last_bit:
last_bit, _ = self.get_attribute(constants.VI_ATTR_ASRL_DATA_BITS)
mask = 1 << (last_bit - 1)
data = common.iter_bytes(data, mask, send_end)
elif end_out == SerialTermination.termination_char:
term_char, _ = self.get_attribute(constants.VI_ATTR_TERMCHAR)
data = common.iter_bytes(data + common.int_to_byte(term_char))
else:
raise ValueError('Unknown value for VI_ATTR_ASRL_END_OUT: %s' % end_out)
count = 0
for d in data:
count += self.interface.write(d)
if end_out == SerialTermination.termination_break:
logger.debug('Serial.sendBreak')
self.interface.sendBreak()
return count, constants.StatusCode.success
except serial.SerialTimeoutException:
return 0, StatusCode.error_timeout
def _get_attribute(self, attribute):
"""Get the value for a given VISA attribute for this session.
Use to implement custom logic for attributes.
:param attribute: Resource attribute for which the state query is made
:return: The state of the queried attribute for a specified resource, return value of the library call.
:rtype: (unicode | str | list | int, VISAStatus)
"""
if attribute == constants.VI_ATTR_ASRL_ALLOW_TRANSMIT:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_AVAIL_NUM:
return self.interface.inWaiting(), SUCCESS
elif attribute == constants.VI_ATTR_ASRL_BAUD:
return self.interface.baudrate, SUCCESS
elif attribute == constants.VI_ATTR_ASRL_BREAK_LEN:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_BREAK_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_CONNECTED:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_CTS_STATE:
return to_state(self.interface.getCTS()), SUCCESS
elif attribute == constants.VI_ATTR_ASRL_DATA_BITS:
return self.interface.bytesize, SUCCESS
elif attribute == constants.VI_ATTR_ASRL_DCD_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_DISCARD_NULL:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_DSR_STATE:
return to_state(self.interface.getDSR()), SUCCESS
elif attribute == constants.VI_ATTR_ASRL_DTR_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_FLOW_CNTRL:
return (self.interface.xonxoff * constants.VI_ASRL_FLOW_XON_XOFF |
self.interface.rtscts * constants.VI_ASRL_FLOW_RTS_CTS |
self.interface.dsrdtr * constants.VI_ASRL_FLOW_DTR_DSR), SUCCESS
elif attribute == constants.VI_ATTR_ASRL_PARITY:
parity = self.interface.parity
if parity == serial.PARITY_NONE:
return constants.Parity.none, SUCCESS
elif parity == serial.PARITY_EVEN:
return constants.Parity.even, SUCCESS
elif parity == serial.PARITY_ODD:
return constants.Parity.odd, SUCCESS
elif parity == serial.PARITY_MARK:
return constants.Parity.mark, SUCCESS
elif parity == serial.PARITY_SPACE:
return constants.Parity.space, SUCCESS
raise Exception('Unknown parity value: %r' % parity)
elif attribute == constants.VI_ATTR_ASRL_RI_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_RTS_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_STOP_BITS:
bits = self.interface.stopbits
if bits == serial.STOPBITS_ONE:
return constants.StopBits.one, SUCCESS
elif bits == serial.STOPBITS_ONE_POINT_FIVE:
return constants.StopBits.one_and_a_half, SUCCESS
elif bits == serial.STOPBITS_TWO:
return constants.StopBits.two, SUCCESS
raise Exception('Unknown bits value: %r' % bits)
elif attribute == constants.VI_ATTR_ASRL_XOFF_CHAR:
raise NotImplementedError
elif attribute == constants.VI_ATTR_INTF_TYPE:
return constants.InterfaceType.asrl, SUCCESS
raise UnknownAttribute(attribute)
def _set_attribute(self, attribute, attribute_state):
"""Sets the state of an attribute.
Corresponds to viSetAttribute function of the VISA library.
:param attribute: Attribute for which the state is to be modified. (Attributes.*)
:param attribute_state: The state of the attribute to be set for the specified object.
:return: return value of the library call.
:rtype: VISAStatus
"""
if attribute == constants.VI_ATTR_ASRL_ALLOW_TRANSMIT:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_BAUD:
self.interface.baudrate = attribute_state
return StatusCode.success
elif attribute == constants.VI_ATTR_ASRL_BREAK_LEN:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_BREAK_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_CONNECTED:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_DATA_BITS:
self.interface.bytesize = attribute_state
return StatusCode.success
elif attribute == constants.VI_ATTR_ASRL_DCD_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_DISCARD_NULL:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_DSR_STATE:
return to_state(self.interface.getDSR())
elif attribute == constants.VI_ATTR_ASRL_DTR_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_FLOW_CNTRL:
if not isinstance(attribute_state, int):
return StatusCode.error_nonsupported_attribute_state
if not 0 < attribute_state < 8:
return StatusCode.error_nonsupported_attribute_state
try:
self.interface.xonxoff = attribute_state & constants.VI_ASRL_FLOW_XON_XOFF
self.interface.rtscts = attribute_state & constants.VI_ASRL_FLOW_RTS_CTS
self.interface.dsrdtr = attribute_state & constants.VI_ASRL_FLOW_DTR_DSR
return StatusCode.success
except:
return StatusCode.error_nonsupported_attribute_state
elif attribute == constants.VI_ATTR_ASRL_PARITY:
if attribute_state == constants.Parity.none:
self.interface.parity = serial.PARITY_NONE
return StatusCode.success
elif attribute_state == constants.Parity.even:
self.interface.parity = serial.PARITY_EVEN
return StatusCode.success
elif attribute_state == constants.Parity.odd:
self.interface.parity = serial.PARITY_ODD
return StatusCode.success
elif attribute_state == serial.PARITY_MARK:
self.interface.parity = serial.PARITY_MARK
return StatusCode.success
elif attribute_state == constants.Parity.space:
self.interface.parity = serial.PARITY_SPACE
return StatusCode.success
return StatusCode.error_nonsupported_attribute_state
elif attribute == constants.VI_ATTR_ASRL_RI_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_RTS_STATE:
raise NotImplementedError
elif attribute == constants.VI_ATTR_ASRL_STOP_BITS:
bits = self.interface.stopbits
if bits == serial.STOPBITS_ONE:
return constants.StopBits.one
elif bits == serial.STOPBITS_ONE_POINT_FIVE:
return constants.StopBits.one_and_a_half
elif bits == serial.STOPBITS_TWO:
return constants.StopBits.two
raise Exception('Unknown bits value: %r' % bits)
elif attribute == constants.VI_ATTR_ASRL_XOFF_CHAR:
raise NotImplementedError
raise UnknownAttribute(attribute)
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