MC68HC08LT8 Datasheet, PDF (111/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 11
Keyboard Interrupt Module (KBI)
11.1 Introduction
The keyboard interrupt module (KBI) provides four independently maskable external interrupts which are
accessible via PTA0–PTA3. When a port pin is enabled for keyboard interrupt function, an internal pull-up
device is also enabled on the pin.
11.2 Features
Features of the keyboard interrupt module include the following:
• Four keyboard interrupt pins with pull-up devices
• Separate keyboard interrupt enable bits and one keyboard interrupt mask
• Programmable edge-only or edge- and level- interrupt sensitivity
• Exit from low-power modes
Addr.
$001B
$001C
Register Name
Bit 7
6
5
4
3
Keyboard Status and ^Read:
0
0
0
0
KEYF
Control Register Write:
(KBSCR) _Reset:
0
0
0
0
0
Keyboard Interrupt ^Read:
0
0
0
0
KBIE3
Enable Register Write:
(KBIER) _Reset:
0
0
0
0
0
= Unimplemented
Figure 11-1. KBI I/O Register Summary
2
0
ACKK
0
KBIE2
0
1
Bit 0
IMASKK MODEK
0
0
KBIE1 KBIE0
0
0
11.3 I/O Pins
The eight keyboard interrupt pins are shared with standard port I/O pins. The full name of the KBI pins
are listed in Table 11-1. The generic pin name appear in the text that follows.
Table 11-1. Pin Name Conventions
KBI Generic Pin Name
KBI0–KBI3
Full MCU Pin Name
PTA0/KBI0–PTA3/KBI3
Pin Selected for KBI Function
by KBIEx Bit in KBIER
KBIE0–KBIE3
MC68HC08LT8 Data Sheet, Rev. 1
Freescale Semiconductor
111