Not able to use "if-else" condition inside "switch-case" event handler

Question

I'm using the Custom service example as by base. Now this was really itching me to not know the reason which causes it. I'm giving an "if-else" condition inside a "switch-case" condition as shown below inside the custom ble service handler as follows. In the BLE_CUS_EVT_NOTIFICATION_ENABLED case to be specific and inside it the if condition checking for the received_data variable : 
 static void on_cus_evt(ble_cus_t * p_cus_service,
 ble_cus_evt_t * p_evt)
{
 ret_code_t err_code;
 BaseType_t xHigherPriorityTaskWoken = pdFALSE;
 switch(p_evt->evt_type)
 {
 case BLE_CUS_EVT_NOTIFICATION_ENABLED:
 if (pdPASS != xTimerStartFromISR(m_cus_notification_timer, &xHigherPriorityTaskWoken))
 {
 APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
 }
 
 if(received_data==1){
 // Enter here, set a breakpoint here
 xTaskResumeFromISR(m_mpu_thread_0);
 }
 break;

 case BLE_CUS_EVT_NOTIFICATION_DISABLED:
 if (pdPASS != xTimerStopFromISR(m_cus_notification_timer, &xHigherPriorityTaskWoken))
 {
 APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
 }

 break;

 case BLE_CUS_EVT_CONNECTED:
 break;

 case BLE_CUS_EVT_DISCONNECTED:
 break;

 default:
 // No implementation needed.
 break;
 }
} 
 received_data is the variable which stores the data written to the service. It is a global variable so I think scope isn't the issue here. When I see my "received_data" in the debug terminal it shows that the value is 1 but it never enters the "if(received_data==1)" condition. 
 
 But if the same thing is done in ble event handler callback function then it's working fine . In the BLE_GATTS_EVT_WRITE event to specific and if condition works here fine : 
 
 static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
 uint32_t err_code;

 switch (p_ble_evt->header.evt_id)
 {
 case BLE_GAP_EVT_CONNECTED:
 m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
 err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
 APP_ERROR_CHECK(err_code);
 break;

 case BLE_GAP_EVT_DISCONNECTED:
 NRF_LOG_INFO("Disconnected");
 m_conn_handle = BLE_CONN_HANDLE_INVALID;
 break;

 case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
 {
 NRF_LOG_DEBUG("PHY update request.");
 ble_gap_phys_t const phys =
 {
 .rx_phys = BLE_GAP_PHY_AUTO,
 .tx_phys = BLE_GAP_PHY_AUTO,
 };
 err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
 APP_ERROR_CHECK(err_code);
 } break;
 
 case BLE_GATTS_EVT_WRITE:
 received_data = p_ble_evt->evt.gatts_evt.params.write.data[0];
 
 if(received_data==1){
 
 xTaskResumeFromISR(m_mpu_thread_0);

 }
 else if(received_data==2){
 xTaskResumeFromISR(m_thread_1);
 }
 break;

 default:
 // No implementation needed.
 break;
 }
} 
 what's the reason that if works in on ble event handler and not in the custom service event handler. Aren't if-else cases applicable anywhere in the code?

Marjeris Romero · Accepted Answer

Hi, 
 To answer you last question. If you take a look at the example code you can see that the application event handler on_cus_init is called inside the on_write function after BLE_GATTS_EVT_WRITE has occured in ble_cus_on_ble_evt and the priorities of ble_cus_on_ble_evt and ble_evt_handler are set as 
 // Register a handler for BLE events.
 NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL); 
 in main.c and 
 NRF_SDH_BLE_OBSERVER(_name ## _obs, \
 BLE_HRS_BLE_OBSERVER_PRIO, \
 ble_cus_on_ble_evt, &_name) 
 in ble_cus.h. BLE_HRS_BLE_OBSERVER_PRIO = 2 in sdk_config.h, and APP_BLE_OBSERVER_PRIO is defined as 3 in main.c. 
 So the callback function for ble_cus_on_ble_evt will have higher priority than ble_evt_handler. 
 Best Regards, 
 Marjeris

Not able to use "if-else" condition inside "switch-case" event handler

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