| 摘要 |
PURPOSE:To realize a low-cost and efficient multipersonality system by incorporating plural processor units different in characteristic in the system switching and operating them and connecting directly input/output signals of plural processor units to make excess driver/receiver circuits unnecessary. CONSTITUTION:If a processor unit (A) 1 requires mode switching by some cause, contents of a flip-flop 31 are rewritten. That is, data (DAT) for processor switching is given through a CPU bus 4, and a mode A signal and a mode B signal are set to the low level and the high level respectively after a write strobe signal -WRT from a control part 34 comes. Then, the reset terminal of the processor unit B is made active through an NOR gate 33, and a bus control signal is set to the floating state. Reset of a processor unit B is released, and the processor unit B can be operated as a CPU bus mask. |
