7 Replies Latest reply on Oct 9, 2016 8:58 AM by userc_27901

    iOT AWS MQTT Subscribe issues on BCM94343AVN

      I am running BCM94343W AVN with build 3.7.0   The device can publish consistently from device to AWS iOT . No issues. However, once I do a device update from AWS to the device ( update shadow ) , the client will never want to receive another request. Eventually the device will reset itself. This is with the standard build and not code changes other than starting it working. the web MQTT client will happily receive multiple shadow updates.


      On the device it will enter into the GET Semiphore code after it parses the JSON and never return on the next item in the delta topic ( which does make it into the queue as the MQTT client at AWS sees the update.


      Anyone see this issue before? I did not change the JSON either .. just out of the box stuff. I have code that modifies the JSON parser but its not causing the problems.





        • 1. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

          You may want to try the Avnet Forum here as well: Avnet BCM4343W IoT Starter Kit | Avnet CloudConnectKits


          I think this is a common issue.

          • 2. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

            Can someone please answer this question.

            • 3. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

              I had the same problem. So removed the shadow functionality and now just use receive messages functionality.



              /* code here to receive and parse messages */

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              • 4. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

                I'm seeing this issue also, and removing the shadow functionality isn't an option. Has there been a resolution?


                userc_28937 were you able to determine a fix?

                • 5. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN


                  On removing the shadow feature are you suggesting just the empty case entries? I need the shadow response which is processed in the MSG_RECEIVED  code section. Can you provide more details on what you specifically removed>?


                  switch ( event->type )


                          case WICED_MQTT_EVENT_TYPE_CONNECT_REQ_STATUS:

                          case WICED_MQTT_EVENT_TYPE_DISCONNECTED:

                          case WICED_MQTT_EVENT_TYPE_PUBLISHED:

                          case WICED_MQTT_EVENT_TYPE_SUBCRIBED:

                          case WICED_MQTT_EVENT_TYPE_UNSUBSCRIBED:


                              app_info.expected_event = event->type;

                              wiced_rtos_set_semaphore( &app_info.msg_semaphore );




                          case WICED_MQTT_EVENT_TYPE_PUBLISH_MSG_RECEIVED:


                              wiced_mqtt_topic_msg_t msg = event->data.pub_recvd;

                  • 6. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

                    Ok. I did not give my best effort in troubleshooting why shadow functionality was not working.


                    So i focused on pushing my data to AWS Platform in "aws/data" topic. Also, to receive messages, i posted them to a "aws/databack" topic, which where then received and parsed in the "case WICED_MQTT_EVENT_TYPE_PUBLISH_MSG_RECEIVED:" section. To post messages to "aws/databack", you can use program like MQTT.fx  or from use AWS MQTT via Websockets if you want to do it in a Web application.


                    To below are the changes made.

                    Hope this helps.


                    aws_common.h file


                    #define THING_STATE_TOPIC_STR_BUILDER       "$aws/things/%s/shadow/update"

                    #define THING_DELTA_TOPIC_STR_BUILDER       "$aws/things/%s/shadow/update/delta"

                    #define THING_TOPIC_DATA       "aws/data"           // topic to send data to AWS

                    #define THING_TOPIC_DATA       "aws/databack"   // subscribed topic

                    typedef struct aws_app_info_s


                        wiced_mqtt_event_type_t   expected_event;

                        wiced_semaphore_t         msg_semaphore;

                        wiced_semaphore_t         wake_semaphore;

                        char                      thing_name[32];

                        char                      shadow_state_topic[64];

                        char                      shadow_delta_topic[64];

                        char                      thing_topic_data[64];

                        char                      thing_topic_databack[64];

                        char                      mqtt_client_id[64];

                        wiced_mqtt_object_t       mqtt_object;

                    } aws_app_info_t;



                    In shadow.c, you are not subscribing to the shadow topic, but to your custom topic

                    Below is example of changes in application_start()


                    void application_start( void )


                        wiced_result_t  ret = WICED_SUCCESS;

                        int             connection_retries = 0;

                        char payload[1];


                        sprintf(payload, "{\"serial\":%s,\"tmptr\":%.1f}","\"S1\"",15.0);

                        ret = aws_app_init(&app_info);

                        wiced_gpio_input_irq_enable( WICED_BUTTON1, IRQ_TRIGGER_RISING_EDGE, setpoint_control_keypad_handler, NULL );




                            ret = aws_mqtt_conn_open( app_info.mqtt_object, mqtt_connection_event_cb );

                            connection_retries++ ;

                        } while ( ( ret != WICED_SUCCESS ) && ( connection_retries < WICED_MQTT_CONNECTION_NUMBER_OF_RETRIES ) );



                        aws_mqtt_app_publish( app_info.mqtt_object, WICED_MQTT_QOS_DELIVER_AT_LEAST_ONCE, (uint8_t*)app_info.thing_topic_data, (uint8_t*)payload ,strlen(payload) );

                        wiced_rtos_delay_milliseconds( MQTT_DELAY_IN_MILLISECONDS * 2 );

                        aws_mqtt_app_subscribe( app_info.mqtt_object, app_info.thing_topic_databack , WICED_MQTT_QOS_DELIVER_AT_LEAST_ONCE );


                        while ( 1 )


                            /* Wait forever on wake semaphore until the wake button is pressed */

                            wiced_rtos_get_semaphore( &app_info.wake_semaphore, WICED_NEVER_TIMEOUT );

                            aws_mqtt_app_publish( app_info.mqtt_object, WICED_MQTT_QOS_DELIVER_AT_LEAST_ONCE, (uint8_t*)app_info.thing_topic_data, (uint8_t*)payload ,strlen(payload) );



                        aws_mqtt_app_unsubscribe( app_info.mqtt_object, app_info.thing_topic_databack);

                        aws_mqtt_conn_close( app_info.mqtt_object );


                        wiced_rtos_deinit_semaphore( &app_info.msg_semaphore );

                        ret = wiced_mqtt_deinit( app_info.mqtt_object );

                        free( app_info.mqtt_object );

                        app_info.mqtt_object = NULL;






                    In shadow.c, to parse incoming data.

                    This example has more detail. You can check if the data is meant for the specific device and turn LED ON or OFF based on message content.




                            // MESSAGE Example: {"serial": "S1","LED": "ON"}

                            cJSON *original, *child, *json;


                            wiced_mqtt_topic_msg_t msg = event->data.pub_recvd;

                            WPRINT_APP_INFO(( "[MQTT] Received %.*s  for TOPIC : %.*s\n\n", (int) msg.data_len, msg.data, (int) msg.topic_len, msg.topic ));


                            if ( strncmp( (char*) msg.topic, "aws/databack", msg.topic_len ) == 0 ){


                           original = cJSON_Parse( strchr( (char*) msg.data, '{' ) );

                           child = original->child;


                           json = NULL;


                           while ( child != NULL )


                           WPRINT_APP_INFO (( "child->string [%s]\n", child->string ));

                           WPRINT_APP_INFO (( "child->value [%s]\n", child->valuestring ));


                           if (strcasecmp(child->valuestring,"S1")==0){

                           WPRINT_APP_INFO (("Serial Matched.\n"));

                          json = child->next;




                        WPRINT_APP_INFO (("Serial Mismatch.\n"));


                         child = child->next;



                      if ( json != NULL )


                      WPRINT_APP_INFO(("json->string [%s]\n", json->string));

                      WPRINT_APP_INFO(("json->value [%s]\n", json->valuestring));


                      if (strcasecmp(json->valuestring,"ON")==0){


                             lstat = 1;

                            wiced_rtos_set_semaphore( &app_info.wake_semaphore );


                      else if (strcasecmp(json->valuestring,"OFF")==0){


                      lstat = 0;

                      wiced_rtos_set_semaphore( &app_info.wake_semaphore );



                      cJSON_Delete( original );





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                    • 7. Re: iOT AWS MQTT Subscribe issues on BCM94343AVN

                      From another thread here: https://community.cypress.com/message/28971


                      Wow.. after weeks of debugging... Works like a charm..


                      Setting QoS to the other value

                      aws_mqtt_app_subscribe( app_info.mqtt_object, app_info.shadow_delta_topic , WICED_MQTT_QOS_DELIVER_AT_MOST_ONCE


                      thank you so much VikramR_26 and AndrewY_86

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