uartat, le910: initial implementation.

uartat is the underlying UART driver, specifically for use with
AT-style command driven devices like modems.

The le910 support is provided in the form of examples that make use
of the uartat driver to interact with the device.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/python/le910.py

@@ -0,0 +1,157 @@
+#!/usr/bin/python
+# Author: Jon Trulson <jtrulson@ics.com>
+# Copyright (c) 2017 Intel Corporation.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+from __future__ import print_function
+import time, sys, signal, atexit
+from upm import pyupm_uartat as UARTAT
+
+def main():
+    ## Exit handlers ##
+    # This function stops python from printing a stacktrace when you
+    # hit control-C
+    def SIGINTHandler(signum, frame):
+        raise SystemExit
+
+    # This function lets you run code on exit, including functions from sensor
+    def exitHandler():
+        print("Exiting")
+        sys.exit(0)
+
+    # Register exit handlers
+    atexit.register(exitHandler)
+    signal.signal(signal.SIGINT, SIGINTHandler)
+
+    defaultDev = "/dev/ttyUSB0"
+
+    # if an argument was specified, use it as the device instead
+    if (len(sys.argv) > 1):
+        defaultDev = sys.argv[1]
+
+    print("Using device:", defaultDev);
+
+    # Instantiate a UARTAT sensor on defaultDev at 115200 baud.
+    sensor = UARTAT.UARTAT(defaultDev, 115200)
+
+    # This is a simplistic example that tries to configure the LE910,
+    # and use it's built-in socket capabilities to connect to a
+    # remote host, obtain a small piece of data, and return it.  It's
+    # mainly intended to show you how you can use the various AT
+    # commands supported by the LE910 to perform simple tasks.
+    #
+    # You must have a valid SIM card with an active data plan for
+    # this example to do anything interesting.
+    #
+    # See the LE910 AT Commands reference for full information on
+    # what is possible with this device.  The uartat driver is
+    # intended to make it a little easier to control AT-style
+    # devices, but is by no means a full-featured communication
+    # infrastructure.  A "real" application will probably need to be
+    # much more sophisticated with regard to parsing, doing retries,
+    # etc.
+    #
+    # For experimenting with various AT commands, try using an
+    # interactive terminal emulator like minicom or screen.
+
+    # make sure we are in command mode
+    if (not sensor.inCommandMode()):
+        print("Not in command mode, switching...")
+        sensor.commandMode("+++", 1000)
+
+    # flter out CR's in responses by default
+    sensor.filterCR(True)
+
+    print("Configuring modem...")
+
+    # discard any waiting characters
+    sensor.drain()
+
+    # reset modem
+    sensor.command("ATZ\r")
+
+    # turn off command echo, set verbosity to 1, enable data
+    # connection mode
+    sensor.command("ATE0 V1 +FCLASS=0\r")
+    sensor.drain()
+
+    # Now issue some commands and output the results.
+
+    print("Modem and SIM information:")
+
+    bufferLength = 256
+
+    buffer = sensor.commandWithResponse("AT+ICCID\r", bufferLength)
+    if (buffer):
+        print("ICCID (SIM ID):", buffer)
+
+    buffer = sensor.commandWithResponse("AT+CGSN=1\r", bufferLength)
+    if (buffer):
+        print("IMEI: ", buffer)
+
+    # see if we are on the network....
+    buffer = sensor.commandWithResponse("AT+CREG?\r", bufferLength)
+    if (buffer):
+        print(buffer)
+
+        # look for "CGREG: 0,1" or "CGREG: 0,5"
+        if (sensor.find(buffer, "CREG: 0,1") or
+            sensor.find(buffer, "CREG: 0,5")):
+            print("Connected to the cell data network.")
+
+            # wait up to 5 seconds for responses now...
+            sensor.setResponseWaitTime(5000)
+
+            # setup PDP context (socket 1).  An ERROR repsonse is
+            # possible if the PDP context is already set up.
+            sensor.command("AT#SGACT=1,1\r")
+
+            # setup a TCP socket to nist.gov and read the timestamp.
+
+            print("Connecting to time-a.nist.gov, TCP port 13")
+
+            # Wait up to 60 seconds to find the NO CARRIER
+            # string, which will be present at the end, if the
+            # connection succeeded and the requested data was
+            # obtained.
+            buffer = sensor.commandWaitFor("AT#SD=1,0,13,\"time-a.nist.gov\"\r",
+                                           bufferLength, "\nNO CARRIER\n", 60000)
+            if (buffer):
+                # print out the response
+                print("RESPONSE: ")
+                print(buffer)
+            else:
+                print("No response.")
+
+            # destroy PDP context
+            sensor.setResponseWaitTime(250)
+            sensor.command("AT#SGACT=1,0\r")
+        else:
+            print("You do not appear to be connected to the network...")
+    else:
+        print("Error executing query\n")
+
+    # reset the modem
+    sensor.command("ATZ\r")
+
+
+if __name__ == '__main__':
+    main()