mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 87

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

9.7 I/O Signals
The KBI module can share its pins with the general-purpose I/O pins. See
are shared.
9.7.1 KBI Input Pins (KBIx:KBI0)
Each KBI pin is independently programmable as an external interrupt source. KBI pin polarity can be
controlled independently. Each KBI pin when enabled will automatically configure the appropriate
pullup/pulldown device based on polarity.
9.8 Registers
The following registers control and monitor operation of the KBI module:
9.8.1 Keyboard Status and Control Register (KBSCR)
Features of the KBSCR:
Bits 7–4 — Not used
KEYF — Keyboard Flag Bit
ACKK — Keyboard Acknowledge Bit
IMASKK— Keyboard Interrupt Mask Bit
MODEK — Keyboard Triggering Sensitivity Bit
Freescale Semiconductor
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This read-only bit is set when a keyboard interrupt is pending.
Writing a 1 to this write-only bit clears the KBI request. ACKK always reads 0.
Writing a 1 to this read/write bit prevents the output of the KBI latch from generating interrupt requests.
This read/write bit controls the triggering sensitivity of the keyboard interrupt pins.
1 = Keyboard interrupt pending
0 = No keyboard interrupt pending
1 = Keyboard interrupt requests disabled
0 = Keyboard interrupt requests enabled
1 = Keyboard interrupt requests on edge and level
0 = Keyboard interrupt requests on edge only
KBSCR (keyboard interrupt status and control register)
KBIER (keyboard interrupt enable register)
KBIPR (keyboard interrupt polarity register)
Flags keyboard interrupt requests
Acknowledges keyboard interrupt requests
Masks keyboard interrupt requests
Controls keyboard interrupt triggering sensitivity
Reset:
Read:
Write:
Figure 9-3. Keyboard Status and Control Register (KBSCR)
Bit 7
0
0
= Unimplemented
6
0
0
MC68HC908QB8 Data Sheet, Rev. 2
5
0
0
0
4
0
KEYF
3
0
ACKK
2
0
0
Figure 9-1
IMASKK
1
0
MODEK
for the port pins that
Bit 0
0
I/O Signals
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