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MC908AS60ACFU Datasheet, PDF (305/414 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers | |||
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24.7.1 Keyboard Status and Control Register
The keyboard status and control register:
⢠Flags keyboard interrupt requests
⢠Acknowledges keyboard interrupt requests
⢠Masks keyboard interrupt requests
⢠Controls keyboard interrupt triggering sensitivity
I/O Registers
Address: $001B
Bit 7
6
5
4
3
2
1
Bit 0
Read: 0
0
0
0
KEYF
0
IMASKK MODEK
Write:
ACKK
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
Figure 24-3. Keyboard Status and Control Register (KBSCR)
Bits 7â4 â Not used
These read-only bits always read as logic 0s.
KEYF â 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
ACKK â Keyboard Acknowledge Bit
Writing a logic 1 to this write-only bit clears the keyboard interrupt request. ACKK always reads as logic
0. Reset clears ACKK.
IMASKK â Keyboard Interrupt Mask Bit
Writing a logic 1 to this read/write bit prevents the output of the keyboard interrupt mask from
generating interrupt requests. Reset clears the IMASKK bit.
1 = Keyboard interrupt requests masked
0 = Keyboard interrupt requests not masked
MODEK â Keyboard Triggering Sensitivity Bit
This read/write bit controls the triggering sensitivity of the keyboard interrupt pins. Reset clears
MODEK.
1 = Keyboard interrupt requests on falling edges and low levels
0 = Keyboard interrupt requests on falling edges only
MC68HC908AZ60A ⢠MC68HC908AS60A ⢠MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
305
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