MC68HC908RK2 Datasheet, PDF (90/158 Pages) Motorola, Inc – Microcontroller Unit

Keyboard/External Interrupt Module (KBI)
7.5 I/O Registers
These registers control and monitor operation of the keyboard/external interrupt module:
• IRQ and keyboard status and control register (INTKBSCR)
• Keyboard interrupt enable register (KBIER)
7.5.1 IRQ and Keyboard Status and Control Register
The IRQ and keyboard status and control register (INTKBSCR) controls and monitors operation of the
keyboard/external interrupt module. The INTKBSCR has these functions:
• Flags the keyboard interrupt requests
• Acknowledges the keyboard interrupt requests
• Masks the keyboard interrupt requests
• Shows the state of the IRQ interrupt flag
• Clears the IRQ interrupt latch
• Masks the IRQ interrupt request
• Controls the triggering sensitivity of the keyboard and IRQ interrupt pins
Address: $001A
Bit 7
Read: IRQF
Write: R
Reset: 0
R
6
5
0
IMASKI
ACKI
0
0
= Reserved
4
MODEI
0
3
KEYF
R
0
2
0
ACKK
0
1
Bit 0
IMASKK MODEK
0
0
Figure 7-6. IRQ and Keyboard Status and Control Register (INTKBSCR)
IRQF — IRQ Flag Bit
This read-only status bit is high when the IRQ interrupt is pending.
1 = IRQ interrupt pending
0 = IRQ interrupt not pending
ACKI — IRQ Interrupt Request Acknowledge Bit
Writing a 1 to this write-only bit clears the IRQ latch. ACKI always reads as 0. Reset clears ACKI.
IMASKI — IRQ Interrupt Mask Bit
Writing a 1 to this read/write bit disables IRQ interrupt requests. Reset clears IMASKI.
1 = IRQ interrupt requests disabled
0 = IRQ interrupt requests enabled
MODEI — IRQ Triggering Sensitivity Bit
This read/write bit controls the triggering sensitivity of the IRQ pin. Reset clears MODEI.
1 = IRQ interrupt requests on falling edges and low levels
0 = interrupt requests on falling edges only
KEYF — Keyboard Flag Bit
This read-only bit is set when a keyboard interrupt is pending. Reset clears the KEYF bit.
1 = Keyboard interrupt pending
0 = No keyboard interrupt pending
MC68HC908RK2 Data Sheet, Rev. 5.1
90
Freescale Semiconductor