DATA PROCESSOR

PURPOSE:To shorten the starting time of the whole system by deciding a processing system means to be restarted among plural processing system means and individually resetting the decided processing system means including a specific sub-CPU or the like. CONSTITUTION:A reset signal 4c is outputted from a reset circuit 3 and inputted to a main CPU 2. The CPU 2 discriminates the processing system requiring rerise, i.e. outputs a reset signal 4b to the sub-CPU 5b to partially reset hardware. At that time, the CPU 2 loads down a control program for the CPU 5b and then applies an execution command. Thereby, the CPU 5b executes self-diagnosis or the initial processing of an overlay processing circuit 6b and then completes its rise. Even when a fault is generated in a text processing circuit 6a or the sub-CPU 5b, similar processing is executed.