| 摘要 |
PURPOSE:To easily access a memory having different access times by providing a clock selecting means controlled by a micro instruction. CONSTITUTION:A CPU 1 is connected to a memory 3 by a data bus 5 and an address bus 6. The CPU contains therein a decoder to a micro instruction inputted through a signal line 7, informs a start of a reading and writing to a memory access control circuit 2 via a control signal on a signal line 8 by an indication of a memory access, and at the same time, outputs a selecting indicating signal to a clock selecting circuit 4 through a signal line 10 and feeds a clock optimum to an access time to a memory access control circuit 2 through a signal line 11. In the memory access control circuit 2, a control signal fed from the CPU1 through the signal line 8 and the optimum clock from the clock selecting circuit 4 are inputted to form an access control signal to the memory 3, feed to a signal line 9 and perform a memory access. |
