MC68HC908GT16 Datasheet, PDF (229/412 Pages) Motorola, Inc – Microcontrollers

16.3 Port A
Input/Output (I/O) Ports
Port A
Port A is an 8-bit special-function port that shares all eight of its pins with
the keyboard interrupt (KBI) module. Port A also has software
configurable pullup devices if configured as an input port.
16.3.1 Port A Data Register
The port A data register (PTA) contains a data latch for each of the eight
port A pins.
Address: $0000
Bit 7
6
5
4
3
2
1
Read:
PTA7
Write:
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
Reset:
Unaffected by reset
Alternate
Function:
KBD7
KBD6
KBD5
KBD4
KBD3
KBD2
KBD1
Figure 16-2. Port A Data Register (PTA)
Bit 0
PTA0
KBD0
PTA7–PTA0 — 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.
KBD7–KBD0 — Keyboard Inputs
The keyboard interrupt enable bits, KBIE7–KBIE0, in the keyboard
interrupt control register (KBICR) enable the port A pins as external
interrupt pins. See Section 13. Keyboard Interrupt Module (KBI).
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
MOTOROLA
Input/Output (I/O) Ports
Technical Data
229