Datasheet

V850ES/JG3 CHAPTER 20 KEY INTERRUPT FUNCTION

R01UH0015EJ0300 Rev.3.00 Page 672 of 870

Sep 30, 2010

20.2 Register

(1) Key return mode register (KRM)

The KRM register controls the KRM0 to KRM7 bits using the KR0 to KR7 signals.

This register can be read or written in 8-bit or 1-bit units.

Reset sets this register to 00H.

KRM7

Does not detect key return signal

Detects key return signal

KRMn

Control of key return mode

KRM KRM6 KRM5 KRM4 KRM3 KRM2 KRM1 KRM0

After reset: 00H R/W Address: FFFFF300H

Caution Rewrite the KRM register after once clearing the KRM register to 00H.

Remark For the alternate-function pin settings, see Table 4-15 Using Port Pin as Alternate-

Function Pin.

20.3 Cautions

(1) If a low level is input to any of the KR0 to KR7 pins, the INTKR signal is not generated even if the falling edge of

another pin is input.

(2) The RXDA1 and KR7 pins must not be used at the same time. To use the RXDA1 pin, do not use the KR7 pin. To

use the KR7 pin, do not use the RXDA1 pin (it is recommended to set the PFC91 bit to 1 and clear PFCE91 bit to

0).

(3) If the KRM register is changed, an interrupt request signal (INTKR) may be generated. To prevent this, change the

KRM register after disabling interrupts (DI) or masking, then clear the interrupt request flag (KRIC.KRIF bit) to 0,

and enable interrupts (EI) or clear the mask.

(4) To use the key interrupt function, be sure to set the port pin to the key return pin and then enable the operation

with the KRM register. To switch from the key return pin to the port pin, disable the operation with the KRM