def write(self, data):
"""Output the given byte string over the serial port."""
if not self.is_open:
raise PortNotOpenError()
d = to_bytes(data)
tx_len = length = len(d)
timeout = Timeout(self._write_timeout)
while tx_len > 0:
try:
n = os.write(self.fd, d)
if timeout.is_non_blocking:
# Zero timeout indicates non-blocking - simply return the
# number of bytes of data actually written
return n
elif not timeout.is_infinite:
# when timeout is set, use select to wait for being ready
# with the time left as timeout
if timeout.expired():
raise SerialTimeoutException('Write timeout')
abort, ready, _ = select.select([self.pipe_abort_write_r],
[self.fd], [],
timeout.time_left())
if abort:
os.read(self.pipe_abort_write_r, 1000)
break
if not ready:
raise SerialTimeoutException('Write timeout')
else:
assert timeout.time_left() is None
# wait for write operation
abort, ready, _ = select.select([self.pipe_abort_write_r],
[self.fd], [], None)
if abort:
os.read(self.pipe_abort_write_r, 1)
break
if not ready:
raise SerialException('write failed (select)')
d = d[n:]
tx_len -= n
except SerialException:
raise
except OSError as e:
# this is for Python 3.x where select.error is a subclass of
# OSError ignore BlockingIOErrors and EINTR. other errors are shown
# https://www.python.org/dev/peps/pep-0475.
if e.errno not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('write failed: {}'.format(e))
except select.error as e:
# this is for Python 2.x
# ignore BlockingIOErrors and EINTR. all errors are shown
# see also http://www.python.org/dev/peps/pep-3151/#select
if e[0] not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('write failed: {}'.format(e))
if not timeout.is_non_blocking and timeout.expired():
raise SerialTimeoutException('Write timeout')
return length - len(d)
def ri(self):
"""Read terminal status line: Ring Indicator"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('returning dummy for ri')
return False
def cd(self):
"""Read terminal status line: Carrier Detect"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('returning dummy for cd)')
return True
def reset_input_buffer(self):
"""Clear input buffer, discarding all that is in the buffer."""
if not self.is_open:
raise PortNotOpenError()
# just use recv to remove input, while there is some
ready = True
while ready:
ready, _, _ = select.select([self._socket], [], [], 0)
try:
if ready:
ready = self._socket.recv(4096)
except OSError as e:
# this is for Python 3.x where select.error is a subclass of
# OSError ignore BlockingIOErrors and EINTR. other errors are shown
# https://www.python.org/dev/peps/pep-0475.
if e.errno not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('read failed: {}'.format(e))
except (select.error, socket.error) as e:
# this is for Python 2.x
# ignore BlockingIOErrors and EINTR. all errors are shown
# see also http://www.python.org/dev/peps/pep-3151/#select
if e[0] not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('read failed: {}'.format(e))
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise PortNotOpenError()
read = bytearray()
timeout = Timeout(self._timeout)
poll = select.poll()
poll.register(self.fd, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL)
poll.register(self.pipe_abort_read_r, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL)
if size > 0:
while len(read) < size:
# print "\tread(): size",size, "have", len(read) #debug
# wait until device becomes ready to read (or something fails)
for fd, event in poll.poll(None if timeout.is_infinite else (timeout.time_left() * 1000)):
if fd == self.pipe_abort_read_r:
break
if event & (select.POLLERR | select.POLLHUP | select.POLLNVAL):
raise SerialException('device reports error (poll)')
# we don't care if it is select.POLLIN or timeout, that's
# handled below
if fd == self.pipe_abort_read_r:
os.read(self.pipe_abort_read_r, 1000)
break
buf = os.read(self.fd, size - len(read))
read.extend(buf)
if timeout.expired() \
or (self._inter_byte_timeout is not None and self._inter_byte_timeout > 0) and not buf:
break # early abort on timeout
return bytes(read)
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise PortNotOpenError()
if self._timeout is not None and self._timeout != 0:
timeout = time.time() + self._timeout
else:
timeout = None
data = bytearray()
while size > 0 and self.is_open:
try:
b = self.queue.get(
timeout=self._timeout) # XXX inter char timeout
except queue.Empty:
if self._timeout == 0:
break
else:
if b is not None:
data += b
size -= 1
else:
break
# check for timeout now, after data has been read.
# useful for timeout = 0 (non blocking) read
if timeout and time.time() > timeout:
if self.logger:
self.logger.info('read timeout')
break
return bytes(data)
def write(self, data):
"""\
Output the given byte string over the serial port. Can block if the
connection is blocked. May raise SerialException if the connection is
closed.
"""
self._cancel_write = False
if not self.is_open:
raise PortNotOpenError()
data = to_bytes(data)
# calculate aprox time that would be used to send the data
time_used_to_send = 10.0 * len(data) / self._baudrate
# when a write timeout is configured check if we would be successful
# (not sending anything, not even the part that would have time)
if self._write_timeout is not None and time_used_to_send > self._write_timeout:
# must wait so that unit test succeeds
time_left = self._write_timeout
while time_left > 0 and not self._cancel_write:
time.sleep(min(time_left, 0.5))
time_left -= 0.5
if self._cancel_write:
return 0 # XXX
raise SerialTimeoutException('Write timeout')
for byte in iterbytes(data):
self.queue.put(byte, timeout=self._write_timeout)
return len(data)
def cts(self):
"""Read terminal status line: Clear To Send"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('CTS -> state of RTS ({!r})'.format(self._rts_state))
return self._rts_state
def cts(self):
"""Read terminal status line: Clear To Send"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('returning dummy for cts')
return True
def dsr(self):
"""Read terminal status line: Data Set Ready"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('returning dummy for dsr')
return True
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise PortNotOpenError()
read = bytearray()
timeout = Timeout(self._timeout)
while len(read) < size:
try:
ready, _, _ = select.select([self.fd, self.pipe_abort_read_r],
[], [], timeout.time_left())
if self.pipe_abort_read_r in ready:
os.read(self.pipe_abort_read_r, 1000)
break
# If select was used with a timeout, and the timeout occurs, it
# returns with empty lists -> thus abort read operation.
# For timeout == 0 (non-blocking operation) also abort when
# there is nothing to read.
if not ready:
break # timeout
buf = os.read(self.fd, size - len(read))
except OSError as e:
# this is for Python 3.x where select.error is a subclass of
# OSError ignore BlockingIOErrors and EINTR. other errors are shown
# https://www.python.org/dev/peps/pep-0475.
if e.errno not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('read failed: {}'.format(e))
except select.error as e:
# this is for Python 2.x
# ignore BlockingIOErrors and EINTR. all errors are shown
# see also http://www.python.org/dev/peps/pep-3151/#select
if e[0] not in (errno.EAGAIN, errno.EALREADY,
errno.EWOULDBLOCK, errno.EINPROGRESS,
errno.EINTR):
raise SerialException('read failed: {}'.format(e))
else:
# read should always return some data as select reported it was
# ready to read when we get to this point.
if not buf:
# Disconnected devices, at least on Linux, show the
# behavior that they are always ready to read immediately
# but reading returns nothing.
raise SerialException(
'device reports readiness to read but returned no data '
'(device disconnected or multiple access on port?)')
read.extend(buf)
if timeout.expired():
break
elif self._inter_byte_timeout is not None and self._inter_byte_timeout > 0:
#atleast one char received --> overwrite timeout by setting it to inter_byte_timeout
timeout = Timeout(self._inter_byte_timeout)
return bytes(read)
def _update_break_state(self):
"""Set break: Controls TXD. When active, to transmitting is possible."""
if not self.is_open:
raise PortNotOpenError()
if self._break_state:
win32.SetCommBreak(self._port_handle)
else:
win32.ClearCommBreak(self._port_handle)
def reset_input_buffer(self):
if not self.is_open:
raise PortNotOpenError()
self._hid_handle.send_feature_report(
bytes((_REPORT_SET_PURGE_FIFOS, _PURGE_RX_FIFO)))
# empty read buffer
while self._read_buffer.qsize():
self._read_buffer.get(False)
def flush(self):
"""\
Flush of file like objects. In this case, wait until all data
is written.
"""
if not self.is_open:
raise PortNotOpenError()
termios.tcdrain(self.fd)
def reset_output_buffer(self):
"""\
Clear output buffer, aborting the current output and discarding all
that is in the buffer.
"""
if not self.is_open:
raise PortNotOpenError()
termios.tcflush(self.fd, termios.TCOFLUSH)
def reset_output_buffer(self):
"""\
Clear output buffer, aborting the current output and discarding all
that is in the buffer.
"""
if not self.is_open:
raise PortNotOpenError()
win32.PurgeComm(self._port_handle, win32.PURGE_TXCLEAR | win32.PURGE_TXABORT)
def in_waiting(self):
"""Return the number of bytes currently in the input buffer."""
if not self.is_open:
raise PortNotOpenError()
# Poll the socket to see if it is ready for reading.
# If ready, at least one byte will be to read.
lr, lw, lx = select.select([self._socket], [], [], 0)
return len(lr)
def fileno(self):
"""\
For easier use of the serial port instance with select.
WARNING: this function is not portable to different platforms!
"""
if not self.is_open:
raise PortNotOpenError()
return self.fd
def send_break(self, duration=0.25):
"""\
Send break condition. Timed, returns to idle state after given
duration.
"""
if not self.is_open:
raise PortNotOpenError()
termios.tcsendbreak(self.fd, int(duration / 0.25))
def in_waiting(self):
"""Return the number of bytes currently in the input buffer."""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
# attention the logged value can differ from return value in
# threaded environments...
self.logger.debug('in_waiting -> {:d}'.format(self.queue.qsize()))
return self.queue.qsize()
def send_break(self, duration=0.25):
"""\
Send break condition. Timed, returns to idle state after given
duration.
"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('ignored send_break({!r})'.format(duration))
def reset_output_buffer(self):
"""\
Clear output buffer, aborting the current output and
discarding all that is in the buffer.
"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('ignored reset_output_buffer')
def out_waiting(self):
"""Return how many bytes the in the outgoing buffer"""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
# attention the logged value can differ from return value in
# threaded environments...
self.logger.debug('out_waiting -> {:d}'.format(self.queue.qsize()))
return self.queue.qsize()
def reset_input_buffer(self):
"""Clear input buffer, discarding all that is in the buffer."""
if not self.is_open:
raise PortNotOpenError()
if self.logger:
self.logger.info('reset_input_buffer()')
try:
while self.queue.qsize():
self.queue.get_nowait()
except queue.Empty:
pass
def write(self, data):
if not self.is_open:
raise PortNotOpenError()
data = to_bytes(data)
tx_len = len(data)
while tx_len > 0:
to_be_sent = min(tx_len, 0x3F)
report = to_bytes([to_be_sent]) + data[:to_be_sent]
self._hid_handle.write(report)
data = data[to_be_sent:]
tx_len = len(data)
def set_output_flow_control(self, enable=True):
"""\
Manually control flow of outgoing data - when hardware or software flow
control is enabled.
WARNING: this function is not portable to different platforms!
"""
if not self.is_open:
raise PortNotOpenError()
if enable:
termios.tcflow(self.fd, termios.TCOON)
else:
termios.tcflow(self.fd, termios.TCOOFF)
def set_input_flow_control(self, enable=True):
"""\
Manually control flow - when software flow control is enabled.
This will send XON (true) or XOFF (false) to the other device.
WARNING: this function is not portable to different platforms!
"""
if not self.is_open:
raise PortNotOpenError()
if enable:
termios.tcflow(self.fd, termios.TCION)
else:
termios.tcflow(self.fd, termios.TCIOFF)
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise PortNotOpenError()
read = bytearray()
buf = os.read(self.fd, size - len(read))
read.extend(buf)
return bytes(read)
def set_output_flow_control(self, enable=True):
"""\
Manually control flow - when software flow control is enabled.
This will do the same as if XON (true) or XOFF (false) are received
from the other device and control the transmission accordingly.
WARNING: this function is not portable to different platforms!
"""
if not self.is_open:
raise PortNotOpenError()
if enable:
win32.EscapeCommFunction(self._port_handle, win32.SETXON)
else:
win32.EscapeCommFunction(self._port_handle, win32.SETXOFF)
def _update_break_state(self):
if not self._hid_handle:
raise PortNotOpenError()
if self._break_state:
self._hid_handle.send_feature_report(
bytes((_REPORT_SET_TRANSMIT_LINE_BREAK, 0)))
else:
# Note that while AN434 states "There are no data bytes in
# the payload other than the Report ID", either hidapi or
# Linux does not seem to send the report otherwise.
self._hid_handle.send_feature_report(
bytes((_REPORT_SET_STOP_LINE_BREAK, 0)))