MC68HC908QC16_07 Datasheet, PDF (85/274 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 8
Keyboard Interrupt Module (KBI)
8.1 Introduction
The keyboard interrupt module (KBI) provides independently maskable external interrupts. The KBI
shares its pins with general-purpose input/output (I/O) port pins. See Figure 8-2 for port location of these
shared pins.
8.2 Features
Features of the keyboard interrupt module include:
• Keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard interrupt
mask
• Programmable edge-only or edge and level interrupt sensitivity
• Edge sensitivity programmable for rising or falling edge
• Level sensitivity programmable for high or low level
• Pullup or pulldown device automatically enabled based on the polarity of edge or level detect
• Exit from low-power modes
8.3 Functional Description
The keyboard interrupt module controls the enabling/disabling of interrupt functions on the KBI pins.
These pins can be enabled/disabled independently of each other.
INTERNAL BUS
KBI0
KBIP0
KBIx
KBIPx
VECTOR FETCH
DECODER
ACKK
RESET
1
0S
KBIE0
TO PULLUP/
PULLDOWN ENABLE
V_DD
D ^CLR Q
CK
KEYF
SYNCHRONIZER
1
0S
KBIEx
KBI LATCH
IMASKK
TO PULLUP/
PULLDOWN ENABLE
MODEK
Figure 8-1. Keyboard Interrupt Block Diagram
KEYBOARD
INTERRUPT
REQUEST
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 3
Freescale Semiconductor
85