| 摘要 |
PURPOSE:To execute self-diagnosis by including a system bus by holding temporarily test data from a CPU in a buffer circuit, and thereafter, giving it to an inspection target, and reading its response data in the CPU through a bus connecting circuit. CONSTITUTION:Test data outputted from a CPU 1 is held in a buffer circuit 8, based on a control signal from a control part 10. Thereafter, by the control signal from the control part 10, a CPU side bus 5a and an inspection target side bus 5b are connected electrically through a bus connecting circuit 9, a response signal from an inspection target side is read in the CPU 1 and the inspection of the inspection target side bus 5b is executed. Subsequently, the bus connecting circuit 9 is turned off, and this time, the test data is supplied to a ROM 2, a RAM 3 and an I/O port 4, etc., being inspection targets through the buffer circuit 8, and its inspection is executed. In such a manner, the self- diagnosis having high reliability can be executed by including a system bus. |
