| 摘要 |
<p>PURPOSE:To attain freely an access to an external address bus without any change of the hardware even when the width of the external address buses is increased by using plural 8-bit constitution address buffer circuits connected to an internal bus properly. CONSTITUTION:A CPU 1 is provided with an ALU 8 connected to an internal data bus 3 and an internal address bus 2, an I/D counter 7 whose increment/ decrement is controlled by an I/D control signal and making count by a CI control signal and an output of a carry flip-flop, and three registers IPL 4, an IPM 5 and an IPH 6 acting like an instruction pointer, and address buffer circuits ABL 9, ABM 10 and ABH 11 connected to the internal address bus 2 and external address buses 12, 13, 14.</p> |
