Add MQTT demo for the cc2538dk platform

examples/cc2538dk/mqtt-demo/Makefile

+DEFINES+=PROJECT_CONF_H=\"project-conf.h\"
+
+all: mqtt-demo
+
+CONTIKI_WITH_IPV6 = 1
+
+APPS += mqtt
+
+CONTIKI=../../..
+include $(CONTIKI)/Makefile.include

examples/cc2538dk/mqtt-demo/Makefile.target

+TARGET = cc2538dk

examples/cc2538dk/mqtt-demo/README.md

+MQTT Demo
+=========
+The MQTT client can be used to:
+
+* Publish sensor readings to an MQTT broker.
+* Subscribe to a topic and receive commands from an MQTT broker
+
+The demo will give some visual feedback with the green LED:
+* Very fast blinking: Searching for a network
+* Fast blinking: Connecting to broker
+* Slow, long blinking: Sending a publish message
+
+Publishing
+----------
+By default the example will attempt to publish readings to an MQTT broker
+running on the IPv6 address specified as `MQTT_DEMO_BROKER_IP_ADDR` in
+`project-conf.h`. This functionality was tested successfully with
+[mosquitto](http://mosquitto.org/).
+
+The publish messages include sensor readings but also some other information,
+such as device uptime in seconds and a message sequence number. The demo will
+publish to topic `iot-2/evt/status/fmt/json`. The device will connect using
+client-id `d:quickstart:cc2538:<device-id>`, where `<device-id>` gets
+constructed from the device's IEEE address.
+
+Subscribing
+-----------
+You can also subscribe to topics and receive commands, but this will only
+work if you use "Org ID" != 'quickstart'. To achieve this, you will need to
+change 'Org ID' (`DEFAULT_ORG_ID`). In this scenario, the device will subscribe
+to:
+
+`iot-2/cmd/+/fmt/json`
+
+You can then use this to toggle LEDs. To do this, you can for example
+use mosquitto client to publish to `iot-2/cmd/leds/fmt/json`. So, to change
+the state of an LED, you would do this:
+
+`mosquitto_pub -h <broker IP> -m "1" -t iot-2/cmd/leds/fmt/json`
+
+Where `broker IP` should be replaced with the IP address of your mosquitto
+broker (the one where you device has subscribed). Replace `-m "1'` with `-m "0"`
+to turn the LED back off.
+
+Bear in mind that, even though the topic suggests that messages are of json
+format, they are in fact not. This was done in order to avoid linking a json
+parser into the firmware. This comment only applies to parsing incoming
+messages, outgoing publish messages use proper json payload.
+
+IBM Quickstart Service
+----------------------
+It is also possible to publish to IBM's quickstart service. To do so, you need
+to undefine `MQTT_DEMO_BROKER_IP_ADDR`.
+
+The device will then try to connect to IBM's quickstart over NAT64, so you will
+need a NAT64 gateway in your network to make this work. A guide on how to
+setup NAT64 is out of scope here.
+
+If you want to use IBM's cloud service with a registered device, change
+'Org ID' (`DEFAULT_ORG_ID`) and provide the 'Auth Token' (`DEFAULT_AUTH_TOKEN`),
+which acts as a 'password', but bear in mind that it gets transported in clear
+text.

examples/cc2538dk/mqtt-demo/project-conf.h

+/*
+ * Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/*---------------------------------------------------------------------------*/
+/**
+ * \addtogroup cc2538-mqtt-demo
+ * @{
+ *
+ * \file
+ * Project specific configuration defines for the MQTT demo
+ */
+/*---------------------------------------------------------------------------*/
+#ifndef PROJECT_CONF_H_
+#define PROJECT_CONF_H_
+/*---------------------------------------------------------------------------*/
+/* User configuration */
+#define MQTT_DEMO_STATUS_LED      LEDS_GREEN
+#define MQTT_DEMO_PUBLISH_TRIGGER &button_right_sensor
+
+/* If undefined, the demo will attempt to connect to IBM's quickstart */
+#define MQTT_DEMO_BROKER_IP_ADDR "aaaa::1"
+/*---------------------------------------------------------------------------*/
+#endif /* PROJECT_CONF_H_ */
+/*---------------------------------------------------------------------------*/
+/** @} */