UPD78F0138 NEC, UPD78F0138 Datasheet - Page 379

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

18.3 Register Controlling Key Interrupt
(1) Key return mode register (KRM)
Cautions 1. If any of the KRM0 to KRM7 bits used is set to 1, set bits 0 to 7 (PU70 to PU77) of the
This register controls the KRM0 to KRM7 bits using the KR0 to KR7 signals, respectively.
This register is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears this register to 00H.
2. If KRM is changed, the interrupt request flag may be set. Therefore, disable interrupts and
3. The bits not used in the key interrupt mode can be used as normal ports.
Symbol
Address: FF6EH
KRM
corresponding pull-up resistor register 7 (PU7) to 1.
then change the KRM register. Clear the interrupt request flag and enable interrupts.
KRMn
KRM7
Figure 18-2. Format of Key Return Mode Register (KRM)
0
1
7
Does not detect key interrupt signal
Detects key interrupt signal
After reset: 00H
KRM6
CHAPTER 18 KEY INTERRUPT FUNCTION
6
User’s Manual U16228EJ2V0UD
KRM5
5
R/W
KRM4
Key interrupt mode control
4
KRM3
3
KRM2
2
KRM1
KRM0
0
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