XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 432

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Keyboard Module (KBD)
24.3 Features
24.4 Functional Description
Technical Data
432
KBD features include:
Writing to the KBIE4–KBIE0 bits in the keyboard interrupt enable register
independently enables or disables each port G or port H 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 a keyboard interrupt request.
A keyboard interrupt is latched when one or more keyboard pins goes
low after all were high. The MODEK bit in the keyboard status and
control register controls the triggering mode of the keyboard interrupt.
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Five Keyboard Interrupt Pins with Separate Keyboard Interrupt
Enable Bits and One Keyboard Interrupt Mask
Hysteresis Buffers
Programmable Edge-Only or Edge- and Level- Interrupt Sensitivity
Automatic Interrupt Acknowledge
Exit from Low-Power Modes
If the keyboard interrupt is edge-sensitive only, a falling edge on a
keyboard pin does not latch an interrupt request if another
keyboard pin is already low. To prevent losing an interrupt request
on one pin because another pin is still low, software can disable
the latter pin while it is low.
If the keyboard interrupt is falling edge- and low level-sensitive, an
interrupt request is present as long as any keyboard pin is low.
Keyboard Module (KBD)
MC68HC908AZ60A — Rev 2.0
MOTOROLA