Datasheet

78K0/Kx2-L CHAPTER 18 KEY INTERRUPT FUNCTION
R01UH0028EJ0400 Rev.4.00 638
Sep 27, 2010
18.3 Register Controlling Key Interrupt
(1) Key return mode register (KRM)
This register controls the KRMn bit using the KRn signal.
KRM is set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears KRM to 00H.
Figure 18-2. Format of Key Return Mode Register (KRM) (78K0/KC2-L)
(a) 40-pin and 44-pin products
0KRM 0 0 0 KRM3 KRM2 KRM1 KRM0
Address: FF6EH After reset: 00H R/W
Symbol
765432 0
(b) 48-pin products
0
Does not detect key interrupt signal
Detects key interrupt signal
KRMn
0
1
Key interrupt mode control
KRM 0 KRM5 KRM4 KRM3 KRM2 KRM1 KRM0
Address: FF6EH After reset: 00H R/W
Symbol
765432 0
Cautions 1. If any of the KRMn bits used is set to 1, set bit n (PU7n) of the corresponding pull-up resistor
register 7 (PU7) to 1.
2. If KRM is changed, the interrupt request flag may be set. Therefore, disable interrupts and then
change the KRM register. Clear the interrupt request flag and enable interrupts.
3. The bits not used in the key interrupt mode can be used as normal ports.
4. For the 40, 44-pin products of 78K0/KC2-L, be sure to set bits 4 to 7 of KRM to “0”. For the 48-
pin products of 78K0/KC2-L, be sure to set bits 6 and 7 of KRM to “0”.
Remark n = 0 to 3: 40-pin and 44-pin products of 78K0/KC2-L
n = 0 to 5: 48-pin products of 78K0/KC2-L
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