Datasheet

Keyboard Interrupt (KBI) Module
MC68HC908GP32 Data Sheet, Rev. 10
108 Freescale Semiconductor
10.8 I/O Signals
The KBI module can share its pins with the general-purpose I/O pins.
10.8.1 KBI Input Pins (KBI7:KBI0)
Each KBI pin is independently programmable as an external interrupt source. Each KBI pin when enabled
will automatically configure a pullup device.
10.9 Registers
The following registers control and monitor operation of the KBI module:
• INTKBSCR (keyboard interrupt status and control register)
• INTKBIER (keyboard interrupt enable register)
10.9.1 Keyboard Status and Control Register (INTKBSCR)
Features of the INTKBSCR:
• Flags keyboard interrupt requests
• Acknowledges keyboard interrupt requests
• Masks keyboard interrupt requests
• Controls keyboard interrupt triggering sensitivity
Bits 7–4 — Not used
KEYF — Keyboard Flag Bit
This read-only bit is set when a keyboard interrupt is pending.
1 = Keyboard interrupt pending
0 = No keyboard interrupt pending
ACKK — Keyboard Acknowledge Bit
Writing a 1 to this write-only bit clears the KBI request. ACKK always reads 0.
IMASKK— Keyboard Interrupt Mask Bit
Writing a 1 to this read/write bit prevents the output of the KBI latch from generating interrupt requests.
1 = Keyboard interrupt requests disabled
0 = Keyboard interrupt requests enabled
MODEK — Keyboard Triggering Sensitivity Bit
This read/write bit controls the triggering sensitivity of the keyboard interrupt pins.
1 = Keyboard interrupt requests on falling edges and low levels
0 = Keyboard interrupt requests on falling edges only
Bit 7654321Bit 0
Read: 0000KEYF 0
IMASKK MODEK
Write:
ACKK
Reset:00000000
= Unimplemented
Figure 10-2. Keyboard Status and Control Register (INTKBSCR)