def __init__(self, device, baudrate=None, parity=None, rtscts=False,
debug=False):
self._terminal = Terminal()
self._device = device
self._baudrate = baudrate or self.DEFAULT_BAUDRATE
self._port = self._open_port(self._device, self._baudrate, parity,
rtscts, debug)
self._resume = False
self._silent = False
self._rxq = deque()
self._rxe = Event()
self._debug = debug
register(self._cleanup)
class MiniTerm:
"""A mini serial terminal to demonstrate pyserial extensions"""
DEFAULT_BAUDRATE = 115200
def __init__(self,
device,
baudrate=None,
parity=None,
rtscts=False,
debug=False):
self._terminal = Terminal()
self._device = device
self._baudrate = baudrate or self.DEFAULT_BAUDRATE
self._port = self._open_port(self._device, self._baudrate, parity,
rtscts, debug)
self._resume = False
self._silent = False
self._rxq = deque()
self._rxe = Event()
self._debug = debug
register(self._cleanup)
def run(self,
fullmode=False,
loopback=False,
silent=False,
localecho=False,
autocr=False):
"""Switch to a pure serial terminal application"""
self._terminal.init(fullmode)
print('Entering minicom mode @ %d bps' % self._port.baudrate)
stdout.flush()
self._resume = True
# start the reader (target to host direction) within a dedicated thread
args = [loopback]
if self._device.startswith('ftdi://'):
# with pyftdi/pyusb/libusb stack, there is no kernel buffering
# which means that a UART source with data burst may overflow the
# FTDI HW buffer while the SW stack is dealing with formatting
# and console output. Use an intermediate thread to pop out data
# out from the HW as soon as it is made available, and use a deque
# to serve the actual reader thread
args.append(self._get_from_source)
sourcer = Thread(target=self._sourcer)
sourcer.setDaemon(1)
sourcer.start()
else:
# regular kernel buffered device
args.append(self._get_from_port)
reader = Thread(target=self._reader, args=tuple(args))
reader.setDaemon(1)
reader.start()
# start the writer (host to target direction)
self._writer(fullmode, silent, localecho, autocr)
def _sourcer(self):
try:
while self._resume:
data = self._port.read(4096)
if not data:
continue
self._rxq.append(data)
self._rxe.set()
except Exception as ex:
self._resume = False
print(str(ex), file=stderr)
interrupt_main()
def _get_from_source(self):
while not self._rxq and self._resume:
if self._rxe.wait(0.1):
self._rxe.clear()
break
if not self._rxq:
return bytearray()
return self._rxq.popleft()
def _get_from_port(self):
try:
return self._port.read(4096)
except OSError as ex:
self._resume = False
print(str(ex), file=stderr)
interrupt_main()
except Exception as ex:
print(str(ex), file=stderr)
return bytearray()
def _reader(self, loopback, getfunc):
"""Loop forever, processing received serial data in terminal mode"""
try:
# Try to read as many bytes as possible at once, and use a short
# timeout to avoid blocking for more data
self._port.timeout = 0.050
while self._resume:
if self._silent:
sleep(0.25)
continue
data = getfunc()
if data:
stdout.write(data.decode('utf8', errors='replace'))
stdout.flush()
if loopback:
self._port.write(data)
except KeyboardInterrupt:
return
except Exception as exc:
print("Exception: %s" % exc)
if self._debug:
print(format_exc(chain=False), file=stderr)
interrupt_main()
def _writer(self, fullmode, silent, localecho, crlf=0):
"""Loop and copy console->serial until EOF character is found"""
while self._resume:
try:
char = self._terminal.getkey()
if fullmode and ord(char) == 0x2: # Ctrl+B
self._cleanup(True)
return
if self._terminal.IS_MSWIN:
if ord(char) in (0, 224):
char = self._terminal.getkey()
self._port.write(self._terminal.getch_to_escape(char))
continue
if ord(char) == 0x3: # Ctrl+C
raise KeyboardInterrupt('Ctrl-C break')
if silent:
if ord(char) == 0x6: # Ctrl+F
self._silent = True
print('Silent\n')
continue
if ord(char) == 0x7: # Ctrl+G
self._silent = False
print('Reg\n')
continue
if localecho:
stdout.write(char.decode('utf8', errors='replace'))
stdout.flush()
if crlf:
if char == b'\n':
self._port.write(b'\r')
if crlf > 1:
continue
self._port.write(char)
except KeyError:
continue
except KeyboardInterrupt:
if fullmode:
if self._terminal.IS_MSWIN:
self._port.write(b'\x03')
continue
self._cleanup(True)
def _cleanup(self, *args):
"""Cleanup resource before exiting"""
if args and args[0]:
print('%sAborting...' % linesep)
try:
self._resume = False
if self._port:
# wait till the other thread completes
sleep(0.5)
try:
rem = self._port.inWaiting()
except IOError:
# maybe a bug in underlying wrapper...
rem = 0
# consumes all the received bytes
for _ in range(rem):
self._port.read()
self._port.close()
self._port = None
print('Bye.')
except Exception as ex:
print(str(ex), file=stderr)
finally:
if self._terminal:
self._terminal.reset()
self._terminal = None
@staticmethod
def _open_port(device, baudrate, parity, rtscts, debug=False):
"""Open the serial communication port"""
try:
from serial.serialutil import SerialException
from serial import PARITY_NONE
except ImportError as exc:
raise ImportError("Python serial module not installed") from exc
try:
from serial import serial_for_url, VERSION as serialver
version = tuple([int(x) for x in serialver.split('.')])
if version < (3, 0):
raise ValueError
except (ValueError, IndexError, ImportError) as exc:
raise ImportError("pyserial 3.0+ is required") from exc
# the following import enables serial protocol extensions
if device.startswith('ftdi:'):
try:
from pyftdi import serialext
serialext.touch()
except ImportError as exc:
raise ImportError("PyFTDI module not installed") from exc
try:
port = serial_for_url(device,
baudrate=baudrate,
parity=parity or PARITY_NONE,
rtscts=rtscts,
timeout=0)
if not port.is_open:
port.open()
if not port.is_open:
raise IOError('Cannot open port "%s"' % device)
if debug:
backend = port.BACKEND if hasattr(port, 'BACKEND') else '?'
print("Using serial backend '%s'" % backend)
return port
except SerialException as exc:
raise IOError(str(exc)) from exc