mc68hc908rf2 Freescale Semiconductor, Inc, mc68hc908rf2 Datasheet - Page 98

• Manufacturer Part Number: mc68hc908rf2
• Description: M68hc08 Microcontrollers Microcontroller / Transmitter
• Manufacturer: Freescale Semiconductor, Inc

Keyboard/External Interrupt Module (KBI)
7.3.3 KBI Module During Break Interrupts
7.3.4 Keyboard Interrupt Pins
Data Sheet
98
TO PULLUP
TO PULLUP
KBD1
KBD6
ENABLE
ENABLE
KB1IE
KB6IE
.
.
.
The system integration module (SIM) controls whether the IRQ1 or keyboard
interrupt latches can be cleared during the break state. The BCFE bit in the break
flag control register (BFCR) enables software to clear the latches during the break
state. (See
To allow software to clear the IRQ1 or keyboard latches during a break interrupt,
write a 1 to the BCFE bit. If a latch is cleared during the break state, it remains
cleared when the MCU exits the break state.
To protect the latch during the break state, write a 0 to the BCFE bit. With BCFE
at 0 (its default state), writing to the ACKI or ACKK bits in the IRQ and keyboard
status and control register during the break state has no effect on the IRQ1 or
keyboard latches.
Writing to the KBIE6–KBIE1 bits in the keyboard interrupt enable register
independently enables or disables each port A pin as a keyboard interrupt pin.
Enabling a keyboard interrupt pin also enables its internal pullup device. A logic 0
applied to an enabled keyboard interrupt pin latches an IRQ1/keyboard interrupt
request.
Figure 7-5. Keyboard Interrupt Block Diagram
Freescale Semiconductor, Inc.
For More Information On This Product,
MODEK
10.7.3 SIM Break Flag Control
Keyboard/External Interrupt Module (KBI)
V
DD
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D
CK
CLR
Q
INTERRUPT LATCH
KEYBOARD
RESET
ACKK
Register.)
IMASKK
VECTOR FETCH
DECODER
SYNCHRONIZER
INTERNAL BUS
MC68HC908RF2 — Rev. 4.0
INTERRUPT
REQUEST
KEYF
IRQ1
KEYBOARD
INTERRUPT
REQUEST
IRQ1/KEYBOARD
INTERRUPT
REQUEST
MOTOROLA