Renesas 16-bit single-chip microcomputer Manual De Usuario

Rev.1.02    Jul 01, 2005    page 73 of 314
REJ09B0126-0102

M16C/6N Group (M16C/6NL, M16C/6NN)

9. Interrupt

This document is under development and its contents are subject to change.

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An NMI interrupt request is generated when input on the NMI pin changes state from high to low. The NMI

interrupt is a non-maskable interrupt.

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The input level of this NMI interrupt input pin can be read by accessing the P8_5 bit in the P8 register.

This pin cannot be used as an input port.

Of P10_4 to P10_7, a key input interrupt request is generated when input on any of the P10_4 to P10_7

pins which has had the PD10_4 to PD10_7 bits in the PD10 register set to “0” (input) goes low. Key input

interrupts can be used as a key-on wake up function, the function which gets the microcomputer out of wait

or stop mode. However, if you intend to use the key input interrupt, do not use P10_4 to P10_7 as analog

input ports. Figure 9.14 shows the block diagram of the key input interrupt. Note, however, that while input

on any pin which has had the PD10_4 to PD10_7 bits set to “0” (input mode) is pulled low, inputs on all other

pins of the port are not detected as interrupts.

Interrupt control circuit

KUPIC register

Key input interrupt 
request

KI3

KI2

KI1

KI0

PU25 bit in PUR2 register 

PD10_7 bit in PD10 register

Pull-up
transistor

 

PD10_7 bit in PD10 register

PD10_6 bit in
PD10 register

PD10_5 bit in
PD10 register

PD10_4 bit in
PD10 register

Pull-up
transistor

Pull-up
transistor

 

Pull-up
transistor

 

CAN0 wake-up interrupt request is generated when a falling edge is input to CRX0. The CAN0 wake-up

interrupt is enabled only when the PortEn bit = 1 (CTX/CRX function) and Sleep bit = 1 (Sleep mode

enabled) in the C0CTLR register. Figure 9.15 shows the block diagram of the CAN0 wake-up interrupt.

Please note that the wake-up message will be lost.

PortEn bit in C0CTLR register

Sleep bit in C0CTLR register

CRX0

Interrupt control 

circuit

C01WKIC register

CAN0 wake-up
interrupt request