In a non-volatile memory system, test data may be retrieved by means of a circuit without the help of firmware. The circuit is triggered into action when it detects an abnormality in the processor or host interface. In such event, it formats the self test or status signals from the various blocks in the non-volatile memory system controller and sends a test message to the outside world without the assistance of the system processor or interface controller. When implemented in memory systems with multiple data lines, only one of the data lines may be utilized for such purpose, thereby allowing the testing to be performed while the system is still performing data transfer. Preferably, the system includes the test mode communication controller, which can select between a test channel and a host interface channel for the test message transfer so that the same testing may be performed when the memory system is in the test package as well as in an encapsulated package. The test message is transmitted repeatedly and the test message is structured so that it is easier for the receiver host to decipher the message without a handshake with the memory system. A communication controller preferably detects whether any of the communication channels is not used by the controller of a non-volatile memory system for sending signals and sends diagnostic signals through such channel.