Reenable BLE after disabling fails in ble_conn_params_init() on freertos

Question

Hi, I'd like to describe an issue i faced during project development. My setup is: nRF52840 + s140 + sdk15+FreeRtos When i disable BLE I call: 
 1) sd_ble_gap_disconnect () . if connected 2) ble_conn_params_stop() 
 3)nrf_sdh_disable_request(); 
 
 When I reenable BLE I call: 
 nrf_sdh_enable_request() 
 nrf_sdh_ble_enable() 
 ble_conn_params_init() 
 .... 
 
 The problem is that ble_conn_params_init() returns NRF_ERROR_INTERNAL at if initing this way. It caused by call err_code = app_timer_create(&p_instance->timer_id,
 APP_TIMER_MODE_SINGLE_SHOT,
 update_timeout_handler);
 if (err_code != NRF_SUCCESS)
 {
 return NRF_ERROR_INTERNAL;
 } 
 For FREERTOS i use app_timer implementation from app_timer_freertos.c inside it the function 
 app_timer_create() has next lines: if (pinfo->osHandle == NULL)
 {
 /* New timer is created */
 memset(pinfo, 0, sizeof(app_timer_info_t));

 timer_mode = (mode == APP_TIMER_MODE_SINGLE_SHOT) ? pdFALSE : pdTRUE;
 pinfo->single_shot = (mode == APP_TIMER_MODE_SINGLE_SHOT);
 pinfo->func = timeout_handler;
 pinfo->osHandle = xTimerCreate(" ", 1000, timer_mode, pinfo, app_timer_callback);

 if (pinfo->osHandle == NULL)
 err_code = NRF_ERROR_NULL;
 }
 else
 {
 /* Timer cannot be reinitialized using FreeRTOS API */
 return NRF_ERROR_INVALID_STATE;
 } 
 and else case is executed. The comment explains why I get an error. 
 /* Timer cannot be reinitialized using FreeRTOS API */ 
 For now I added workaround and skipped error at upper layer but it would be better to get this case fixed in next SDK version. I suggest adding app_timer_remove() and updating ble_conn_params_stop() might be a good option. Or just skip call 
 app_timer_create in case if it already created. Regards,

bfriedk1 · Accepted Answer

Hello - 
 
 In case it is helpful for anyone else bumping into this issue, here is what we did to resolve the problem. These changes were applied to SDK v17.0.0. 
 
 In ble_conn_params.c, we modified the code to call a new app_timer_delete() function: 
 
 ret_code_t ble_conn_params_stop(void)
{
 ret_code_t err_code;

 //lint -save -e681 "Loop not entered" when NRF_BLE_CONN_PARAMS_INSTANCE_COUNT is 0
 for (uint32_t i = 0; i < NRF_BLE_CONN_PARAMS_INSTANCE_COUNT; i++)
 {
 err_code = app_timer_stop(m_conn_params_instances[i].timer_id);

 switch (err_code)
 {
 case NRF_SUCCESS:
 app_timer_delete(m_conn_params_instances[i].timer_id);
 break;

 case NRF_ERROR_INVALID_STATE:
 /* do nothing */
 break;

 case NRF_ERROR_NO_MEM:
 return NRF_ERROR_BUSY;

 case NRF_ERROR_INVALID_PARAM:
 /* fallthrough */
 default:
 return NRF_ERROR_INTERNAL;
 }
 }
 //lint -restore
 return NRF_SUCCESS;
}

Then we added a simple implementation of app_timer_delete() to app_timer_freertos.c: 
 
 uint32_t app_timer_delete(app_timer_id_t timer_id)
{
 app_timer_info_t * pinfo = (app_timer_info_t*)(timer_id);
 TimerHandle_t hTimer = pinfo->osHandle;
 if (hTimer == NULL)
 {
 return NRF_ERROR_INVALID_STATE;
 }

	if (xTimerDelete(hTimer, APP_TIMER_WAIT_FOR_QUEUE) != pdPASS)
	{
 return NRF_ERROR_NO_MEM;
	}
	
	pinfo->osHandle = NULL;

 return NRF_SUCCESS;
}

The app_timer_delete() function sets the pInfo->osHandle to NULL, which allows a new timer to be created after BLE is reenabled. 
 
 Regards, 
 Brian

Reenable BLE after disabling fails in ble_conn_params_init() on freertos

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