| 摘要 |
PURPOSE:To protect a data of an internal memory, by pulling up an address signal in a CPU card, and stabilizing a level of an internal bus. CONSTITUTION:A pull-up resistance 1e is installed to an internal bus 1d in a CPU card 10. Also, an internal memory 1b is protected at the time of DMA transfer between an external memory 3 and an input/output device 2 by pulling up an internal address signal in the CPU card and stabilizing a level of the internal bus. Accordingly, even if a signal in the output direction of a CPU1a becomes in a floating state, an address signal (1d-a) of the internal bus 1d is pulled up by the resistance 1e. Therefore, a level does not become unstable, and accordingly, the contents of the internal memory 1b are not broken down. |
