Current File : //usr/share/doc/python3-serial/examples/at_protocol.py
#! /usr/bin/env python
# encoding: utf-8
"""
Example of a AT command protocol.
https://en.wikipedia.org/wiki/Hayes_command_set
http://www.itu.int/rec/T-REC-V.250-200307-I/en
"""
from __future__ import print_function
import sys
sys.path.insert(0, '..')
import logging
import serial
import serial.threaded
import threading
try:
import queue
except ImportError:
import Queue as queue
class ATException(Exception):
pass
class ATProtocol(serial.threaded.LineReader):
TERMINATOR = b'\r\n'
def __init__(self):
super(ATProtocol, self).__init__()
self.alive = True
self.responses = queue.Queue()
self.events = queue.Queue()
self._event_thread = threading.Thread(target=self._run_event)
self._event_thread.daemon = True
self._event_thread.name = 'at-event'
self._event_thread.start()
self.lock = threading.Lock()
def stop(self):
"""
Stop the event processing thread, abort pending commands, if any.
"""
self.alive = False
self.events.put(None)
self.responses.put('<exit>')
def _run_event(self):
"""
Process events in a separate thread so that input thread is not
blocked.
"""
while self.alive:
try:
self.handle_event(self.events.get())
except:
logging.exception('_run_event')
def handle_line(self, line):
"""
Handle input from serial port, check for events.
"""
if line.startswith('+'):
self.events.put(line)
else:
self.responses.put(line)
def handle_event(self, event):
"""
Spontaneous message received.
"""
print('event received:', event)
def command(self, command, response='OK', timeout=5):
"""
Set an AT command and wait for the response.
"""
with self.lock: # ensure that just one thread is sending commands at once
self.write_line(command)
lines = []
while True:
try:
line = self.responses.get(timeout=timeout)
#~ print("%s -> %r" % (command, line))
if line == response:
return lines
else:
lines.append(line)
except queue.Empty:
raise ATException('AT command timeout ({!r})'.format(command))
# test
if __name__ == '__main__':
import time
class PAN1322(ATProtocol):
"""
Example communication with PAN1322 BT module.
Some commands do not respond with OK but with a '+...' line. This is
implemented via command_with_event_response and handle_event, because
'+...' lines are also used for real events.
"""
def __init__(self):
super(PAN1322, self).__init__()
self.event_responses = queue.Queue()
self._awaiting_response_for = None
def connection_made(self, transport):
super(PAN1322, self).connection_made(transport)
# our adapter enables the module with RTS=low
self.transport.serial.rts = False
time.sleep(0.3)
self.transport.serial.reset_input_buffer()
def handle_event(self, event):
"""Handle events and command responses starting with '+...'"""
if event.startswith('+RRBDRES') and self._awaiting_response_for.startswith('AT+JRBD'):
rev = event[9:9 + 12]
mac = ':'.join('{:02X}'.format(ord(x)) for x in rev.decode('hex')[::-1])
self.event_responses.put(mac)
else:
logging.warning('unhandled event: {!r}'.format(event))
def command_with_event_response(self, command):
"""Send a command that responds with '+...' line"""
with self.lock: # ensure that just one thread is sending commands at once
self._awaiting_response_for = command
self.transport.write(b'{}\r\n'.format(command.encode(self.ENCODING, self.UNICODE_HANDLING)))
response = self.event_responses.get()
self._awaiting_response_for = None
return response
# - - - example commands
def reset(self):
self.command("AT+JRES", response='ROK') # SW-Reset BT module
def get_mac_address(self):
# requests hardware / calibration info as event
return self.command_with_event_response("AT+JRBD")
ser = serial.serial_for_url('spy://COM1', baudrate=115200, timeout=1)
#~ ser = serial.Serial('COM1', baudrate=115200, timeout=1)
with serial.threaded.ReaderThread(ser, PAN1322) as bt_module:
bt_module.reset()
print("reset OK")
print("MAC address is", bt_module.get_mac_address())
Mini Shell