M16C User Manual.pdf

________NMI InterruptMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER______NMI Interrupt______ ______ ______An NMI interrupt is generated when the input to the P85/NMI pin changes from “H” to “L”. The NMI interruptis a non-maskable external interrupt. The pin level can be checked in the port P85 register (bit 5 at address03F016).This pin cannot be used as a normal port input.Key Input InterruptIf the direction register of any of P104 to P107 is set for input and a falling edge is input to that port, a keyinput interrupt is generated. A key input interrupt can also be used as a key-on wakeup function for cancellingthe wait mode or stop mode. However, if you intend to use the key input interrupt, do not use P104 toP107 as A-D input ports. Figure 1.14.11 shows the block diagram of the key input interrupt. Note that if an“L” level is input to any pin that has not been disabled for input, inputs to the other pins are not detected asan interrupt.Pull-uptransistorPort P104-P107 pull-upselect bitPort P107 directionregisterPort P107 direction registerKey input interrupt control register (address 004D16)P107/KI3P106/KI2Pull-uptransistorPort P106 directionregisterInterrupt control circuitKey input interruptrequestPull-uptransistorPort P105 directionregisterP105/KI1Pull-uptransistorPort P104 directionregisterP104/KI0Figure 1.14.11. Block diagram of key input interrupt67