Hello MKolo.2
I am assuming that your are running a custom BLE project on STM32WB55. You can set-up your custom services and characteristics using STM32_WPAN middleware in CubeMX. Lets' focus on a read characteristic with a notify read event (GATT side).
Step 1: Managed the read event
Under STM32_WPAN/App/custom_stm.c you will find the static SVCCTL_EvtAckStatus_t Custom_STM_Event_Handler(void *Event).
You need to identify where is you read characteristic event handler for exemple here we are using "FW" characteristic.
....
else if (read_req->Attribute_Handle == (CustomContext.CustomFwHdle + CHARACTERISTIC_VALUE_ATTRIBUTE_OFFSET))
{
return_value = SVCCTL_EvtAckFlowEnable;
/*USER CODE BEGIN CUSTOM_STM_Service_3_Char_1_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_1 */
Notification.Custom_Evt_Opcode = CUSTOM_STM_FW_READ_EVT; /* evt_Opcode = FW read event */
Custom_STM_App_Notification(&Notification); /* Call Custom_STM_App_Notification to managed the command */
/*USER CODE END CUSTOM_STM_Service_3_Char_1_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_1*/
aci_gatt_allow_read(read_req->Connection_Handle);
/*USER CODE BEGIN CUSTOM_STM_Service_3_Char_1_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_2 */
/*USER CODE END CUSTOM_STM_Service_3_Char_1_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_2*/
} /* if (read_req->Attribute_Handle == (CustomContext.CustomFwHdle + CHARACTERISTIC_VALUE_ATTRIBUTE_OFFSET))*/
....
You need to call Custom_STM_App_Notification() with the correct event.
Step 2: Update and send your value
Under /STM32_WPAN/App_Customapp.c you will find void Custom_STM_App_Notification(Custom_STM_App_Notification_evt_t *pNotification). Find your read event, update your value and send it. Again with the "FW" read characterisitc:
case CUSTOM_STM_FW_READ_EVT:
/* USER CODE BEGIN CUSTOM_STM_FW_READ_EVT */
APP_DBG_MSG("\r\n\r** CUSTOM_STM_FW_READ_EVT \n");
strcpy((char *)NotifyCharData, FW);
Custom_STM_App_Update_Char(CUSTOM_STM_FW, (uint8_t *)NotifyCharData);
/* USER CODE END CUSTOM_STM_FW_READ_EVT */
break;
You have successfully managed to return the read characteristic to the client.
Hope this will help,
beST regards,
Axel L.
