MQTT Rx Queue

When AnyNet SMARTconnect™ is subscribed to a topic and receives new MQTT messages, it can perform either of the following functions:

• Immediately forward the messages on the AT port in URC format – +EMQ: <id>,<len>,<data>

  where:

  id – is the message index number

  len – is the message length in bits

  data – is the forwarded MQTT message

• If the MQTT Rx Queue is enabled, store up to three MQTT messages in a queue in the module’s volatile memory.

  If AnyNet SMARTconnect™ receives further messages, it overwrites the existing messages, starting with the oldest.

  Messages are stored in the following format – +EMQREAD: <id><len>\r\n<data>

  Use the [mqtt] mqttenablerxqueue parameter in the configuration file to enable or disable the MQTT Rx Queue. For more information, see mqttenablerxqueue.

Status Flags

If the MQTT Rx Queue is enabled, you can use the following status flags to obtain information about the internal status of AnyNet SMARTconnect™:

• MQTT RX – set when messages appear in the MQTT Rx Queue, cleared when no messages exist.
• MQTT RXov – set when the oldest received message is overwritten because of overflow, cleared when the status flags are read.

• MQTT TX Internal error – set when AnyNet SMARTconnect™ is unable to save the MQTT message in the non-volatile memory, cleared when the status flags are read.

• MQTT TXov – set when the oldest transmitted message is overwritten because of overflow, cleared when the status flags are read.

• MQTT TX OK – set when the transmitted message is successfully published, cleared when the status flags are read.

• MQTT TX Refused – set when the MQTT broker rejects the transmitted MQTT message, or closes the SSL connection five consecutive times after each publication attempt. Cleared when the status flags are read.

• Reboot required – set when a reboot is required in order to apply an update, cleared when AnyNet SMARTconnect™ resets.

• Update fail – set when a host firmware, configuration, or AnyNet SMARTconnect™ update fails, cleared when the status flags are read.

• Update success – set when an update completes successfully for host firmware, configuration, AnyNet SMARTconnect™, or AnyNet SMARTconnect™ and modem firmware, cleared when the status flags are read.

Check the status flags using the AT+ETMINFO command. For more information, see ETMINFO – displays AnyNet SMARTconnect™ and device information.