| 摘要 |
PURPOSE:To attain an interrupt request circuit where the circuit per one interrupt input is simplified and the response time for interrupt is shorter by using a transparent latch circuit of an interrupt factor. CONSTITUTION:When an output Q of any one of plural interrupt request FFs 5a-5n becomes H, the output of an interrupt request OR gate 11 becomes H. At this time, if an interrupt factor read signal 8 is in the H state and ineffective, an interrupt request signal 12 to a CPU of the system is set to the H state and is made effective, and a pertinent output Q of an interrupt factor transparent latch circuit 17 is set to the H state and is made effective. For the purpose of performing the interrupt processing by the interrupt request signal 12, the CPU sets the read signal to the L state to make it effective and reads interrupt factors. The interrupt request signal 12 becomes effective, and the circuit 17 latches interrupt factors inputted till then and resets FFs 5a-5n corresponding to H-state effective interrupt factors. |
