mc68hc908kx8 Freescale Semiconductor, Inc, mc68hc908kx8 Datasheet - Page 99

• Manufacturer Part Number: mc68hc908kx8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

9.6 I/O Registers
Two registers control and monitor operation of the keyboard module:
9.6.1 Keyboard Status and Control Register
The keyboard status and control register (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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These read-only bits always read as 0s.
This read-only bit is set when a keyboard interrupt is pending. Reset clears the KEYF bit.
Writing a 1 to this write-only bit clears the keyboard interrupt request. ACKK always reads as 0. Reset
clears ACKK.
Writing a 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating
interrupt requests. Reset clears the IMASKK bit.
This read/write bit controls the triggering sensitivity of the keyboard interrupt pins. Reset clears
MODEK.
1 = Keyboard interrupt pending
0 = No keyboard interrupt pending
1 = Keyboard interrupt requests masked
0 = Keyboard interrupt requests not masked
1 = Keyboard interrupt requests on falling edges and low levels
0 = Keyboard interrupt requests on falling edges only
Keyboard status and control register, KBSCR
Keyboard interrupt enable register, KBIER
Flags keyboard interrupt requests
Acknowledges keyboard interrupt requests
Masks keyboard interrupt requests
Controls keyboard interrupt triggering sensitivity
Address: $001A
Reset:
Read:
Write:
Figure 9-4. Keyboard Status and Control Register (KBSCR)
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
Bit 7
0
0
= Unimplemented
6
0
0
5
0
0
4
0
0
KEYF
3
0
ACKK
2
0
0
IMASKK
1
0
MODEK
Bit 0
0
I/O Registers
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