MC68HC908RK2 Datasheet, PDF (91/158 Pages) Motorola, Inc – Microcontroller Unit

I/O Registers
ACKK — 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 — 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 — 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
7.5.2 Keyboard Interrupt Enable Register
The keyboard interrupt enable register (INTKBIER) enables or disables each port A pin to operate as a
keyboard interrupt pin.
Address: $001B
Bit 7
6
5
4
3
2
1
Bit 0
Read: 0
0
KBIE6 KBIE5 KBIE4 KBIE3 KBIE2 KBIE1
Write:
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
Figure 7-7. Keyboard Interrupt Enable Register (INTKBIER)
KBIE6–KBIE1 — Keyboard Interrupt Enable Bits
Each of these read/write bits enables the corresponding keyboard interrupt pin to latch interrupt
requests. These bits also enable the corresponding internal pullup resistor which is enabled only when
the bit is set. Reset clears the keyboard interrupt enable register.
1 = PAx pin enabled as keyboard interrupt pin and corresponding internal pullup resistor enabled
0 = PAx pin not enabled as keyboard interrupt pin and corresponding internal pullup resistor
disabled
NOTE
Setting a keyboard interrupt enable bit (KBIEx) forces the corresponding
keyboard interrupt pin to be an input, overriding the data direction register.
However, the data direction register bit must be a 0 for software to read the
pin.
MC68HC908RK2 Data Sheet, Rev. 5.1
Freescale Semiconductor
91