| 摘要 |
PURPOSE:To remove a test exclusive terminal, and to simplify the constitution by controlling directly an address bus control circuit by a CPU so that a direct memory access can be executed, at the time of testing. CONSTITUTION:At the time of normal operating, a memory 1 is operated, based on an address and a control signal outputted through an address bus 2 from a CPU 11. Also, this microcomputer is constituted so that an address bus control circuit 10 can be controlled directly by the CPU 11, at the time of testing. That is, on the same chip, the memory 1, the address bus 2 and the circuit 10 for controlling the bus 2 are provided, and an address from an address bus terminal 3 can be transferred directly to the memory 1. In such a state, when an instruction exists at the time of testing, the circuit 10 is controlled directly by the CPU 11, and this circuit 10 is turned on and a direct memory access is executed. In such a way, a test exclusive terminal is made unnecessary and the constitution can be simplified. |
