| 摘要 |
PURPOSE:To change property of an RAM, by installing a latch circuit which controls the write permit signal of the RAM on the RAM board. CONSTITUTION:A board address signal 50 which assigns the board on which an RAM10 is installed and an inversion output signal of a read/write control signal 60 obtained through an invertor 601 is added to an NAND circuit for controlling latch circuit 70, and the output signal of this NAND circuit 70 is connected to a clock terminal CK of a latch circuit 30. An inversion output signal 6011 of the invertor 601 is added to a write permit terminal of the RAM10 through another NAND circuit for changing property of an RAM80. Both read/write control signal 60 and the board address signal 50 are added to the NAND circuit for controlling a tri-state buffer 90, and an output signal 901 of this NAND circuit 90 is added to an output permit terminal of a tri-state buffer 40. |
