MC68HC908GT16 Datasheet, PDF (226/412 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
16.2 Introduction
Bidirectional input-output (I/O) pins form five parallel ports. All I/O pins
are programmable as inputs or outputs. All individual bits within port A,
port C, and port D are software configurable with pullup devices if
configured as input port bits. The pullup devices are automatically and
dynamically disabled when a port bit is switched to output mode.
NOTE:
Connect any unused I/O pins to an appropriate logic level, either V_DD or
V_SS. Although the I/O ports do not require termination for proper
operation, termination reduces excess current consumption and the
possibility of electrostatic damage.
Addr. Register Name
Bit 7
6
5
$0000
Read:
Port A Data Register
(PTA) Write:
See page 229.
Reset:
PTA7
PTA6
PTA5
$0001
Read:
Port B Data Register
(PTB) Write:
See page 233.
Reset:
PTB7
PTB6
PTB5
$0002
Read: 0
Port C Data Register
(PTC) Write:
See page 236.
Reset:
PTC6 PTC5
$0003
Read:
Port D Data Register
(PTD) Write:
See page 240.
Reset:
PTD7
PTD6
PTD5
$0004
Read:
Data Direction Register A
(DDRA) Write:
See page 230.
Reset:
DDRA7
0
DDRA6
0
DDRA5
0
= Unimplemented
4
3
PTA4 PTA3
Unaffected by reset
PTB4 PTB3
Unaffected by reset
PTC4 PTC3
Unaffected by reset
PTD4 PTD3
Unaffected by reset
DDRA4 DDRA3
0
0
2
PTA2
PTB2
PTC2
PTD2
DDRA2
0
1
PTA1
PTB1
PTC1
PTD1
DDRA1
0
Bit 0
PTA0
PTB0
PTC0
PTD0
DDRA0
0
Figure 16-1. I/O Port Register Summary
Technical Data
226
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
Input/Output (I/O) Ports
MOTOROLA