MC68HC908LJ24 Datasheet, PDF (380/464 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
18.3 Port A
Port A is an 8-bit special function port that shares four of its port pins with
the analog-to-digital converter (ADC) module and four of its port pins
with the keyboard interrupt module (KBI).
18.3.1 Port A Data Register (PTA)
The port A data register contains a data latch for each of the eight port A
pins.
Address: $0000
Read:
Write:
Bit 7
PTA7
6
PTA6
5
PTA5
4
PTA4
3
PTA3
2
PTA2
Reset:
Unaffected by Reset
Alternative Function: ADC3 ADC2 ADC1 ADC0 KBI3
KBI2
Figure 18-2. Port A Data Register (PTA)
1
PTA1
KBI1
Bit 0
PTA0
KBI0
PTA[7:0] — Port A Data Bits
These read/write bits are software programmable. Data direction of
each port A pin is under the control of the corresponding bit in data
direction register A. Reset has no effect on port A data.
KBI[3:0] — Keyboard Interrupt Channels 3 to 0
KBI[3:0] are pins used for the keyboard interrupt input. The
corresponding input, KBI[3:0], can be enabled in the keyboard
interrupt enable register, KBIER. Port pins used as KBI input will
override any control from the port I/O logic. See Section 20.
Keyboard Interrupt Module (KBI).
Data Sheet
380
Input/Output (I/O) Ports
MC68HC908LJ24/LK24 — Rev. 2.1
Freescale Semiconductor