I am using aci_gatt_update_char_value() on a BlueNRG-MS to send notifications to a master device. The first number of times this function is called it returns BLE_STATUS_SUCCESS but then it returns BLE_STATUS_INSUFFICIENT_RESOURCES. After this I wait for the EVT_BLUE_GATT_TX_POOL_AVAILABLE before attempting to call aci_gatt_update_char_value() and I am able to send more notifications. The problem is that it takes 4 to 5 seconds to get the Tx pool available event but I am using a connection interval of 100ms so this delay seems way to big. I am using the latest BlueNRG firmware (v7.2c) and using Stack Mode 4.