Portable electronic device with self-diagnostic function

A portable data processing device comprising:

• first self-diagnosis means for, after the portable data processing device is connected to and activated by an external device, performing a portion of self-diagnosis of whether the data processing device operates properly;
• initial response transmit means for, after the portion of the self-diagnosis is terminated by the first self-diagnosis means, transmitting all initial response data to the external device;
• second self-diagnosis means for making the remaining portions of the self-diagnosis after the initial response transmit means has transmitted the initial response data to the external device and, when a command is received from the external device while the self-diagnosis is being performed, suspending the self-diagnosis to receive the command, resuming the self-diagnosis on termination of the reception of the command;
• and
• command processing means for performing corresponding processing to the received command after the termination of the self-diagnosis by the second self-diagnosis means.