MC908GZ60CFUE Datasheet, PDF (117/352 Pages) Freescale Semiconductor, Inc – Standard features, Features of the CPU08

Functional Description
The KBIP7–KBIP0 bits determine the polarity of the keyboard pin detection. These bits along with the
MODEK bit determine whether a logic level (0 or 1) and/or a falling (or rising) edge is being detected.
• If the keyboard interrupt is edge-sensitive only, a falling (or rising) edge on a keyboard pin does not
latch an interrupt request if another keyboard pin is already asserted. To prevent losing an interrupt
request on one pin because another pin is still asserted, software can disable the latter pin while it
is asserted.
• If the keyboard interrupt is edge and level sensitive, an interrupt request is present as long as any
keyboard interrupt pin is asserted and the pin is keyboard interrupt enabled.
INTERNAL BUS
KBD0
KBIP0
KBD7
KBIP7
VECTOR FETCH
DECODER
ACKK
RESET
1
0S
KBIE0
TO PULLUP/
PULLDOWN ENABLE
V_DD
CLR
D
Q
CK
KEYF
SYNCHRONIZER
1
0S
KBIE7
IMASKK
TO PULLUP/
PULLDOWN ENABLE
MODEK
Figure 9-2. Keyboard Module Block Diagram
KEYBOARD
INTERRUPT
REQUEST
Addr.
Register Name
Bit 7
6
5
4
3
Keyboard Status and Control ^Read:
0
0
0
0
KEYF
$001A
Register (INTKBSCR) Write:
See page 120. _Reset:
0
0
0
0
0
$001B
Keyboard Interrupt Enable ^Read:
Register (INTKBIER) Write:
See page 121. _Reset:
KBIE7
0
KBIE6
0
KBIE5
0
KBIE4
0
KBIE3
0
$0448
Keyboard Interrupt Polarity ^Read:
Register (INTKBIPR) Write:
See page 121. _Reset:
KBIP7
0
KBIP6
0
KBIP5
0
KBIP4
0
KBIP3
0
= Unimplemented
Figure 9-3. I/O Register Summary
2
0
ACKK
0
KBIE2
0
KBIP2
0
1
Bit 0
IMASKK MODEK
0
0
KBIE1 KBIE0
0
0
KBIP1 KBIP0
0
0
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Freescale Semiconductor
117