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CHAPTER 19 KEY INTERRUPT FUNCTION
User’s Manual U19780EJ2V0UD
536
19.3 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 19-2. Format of Key Return Mode Register (KRM)
Address: FF6EH After reset: 00H R/W
Symbol
7 6 5 4 3 2 1 0
KRM
0
0
KRM5 KRM4 KRM3 KRM2 KRM1 KRM0
KRMn
Key interrupt mode control
0
Does not detect key interrupt signal
1
Detects key interrupt signal
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. Be sure to set bits 6 and 7 of KRM to “0”.
Remark
n = 0, 5