|
MC908KX2MDWE Datasheet, PDF (99/210 Pages) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families | |||
|
◁ |
9.6 I/O Registers
Two registers control and monitor operation of the keyboard module:
⢠Keyboard status and control register, KBSCR
⢠Keyboard interrupt enable register, KBIER
I/O Registers
9.6.1 Keyboard Status and Control Register
The keyboard status and control register (KBSCR):
⢠Flags keyboard interrupt requests
⢠Acknowledges keyboard interrupt requests
⢠Masks keyboard interrupt requests
⢠Controls keyboard interrupt triggering sensitivity
Address: $001A
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 9-4. Keyboard Status and Control Register (KBSCR)
Bits 7â4 â Not used
These read-only bits always read as 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 1 to this write-only bit clears the keyboard interrupt request. ACKK always reads as 0. Reset
clears ACKK.
IMASKK â Keyboard Interrupt Mask Bit
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.
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
MC68HC908KX8 ⢠MC68HC908KX2 ⢠MC68HC08KX8 Data Sheet, Rev. 2.1
Freescale Semiconductor
99
|
▷ |