MC68HC908GZ8 Datasheet, PDF (199/344 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Data Sheet — MC68HC908GZ8
Section 17. Input/Output (I/O) Ports
17.1 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.
Not all port pins are bonded out in all packages. Care sure be taken to make any
unbonded port pins an output to reduce them from being floating inputs.
Addr.
Register Name
$0000
Read:
Port A Data Register (PTA)
See page 202.
Write:
Reset:
$0001
Read:
Port B Data Register (PTB)
See page 204.
Write:
Reset:
$0002
Read:
Port C Data Register (PTC)
See page 207.
Write:
Reset:
$0003
Read:
Port D Data Register (PTD)
See page 210.
Write:
Reset:
Bit 7
PTA7
PTB7
1
PTD7
6
PTA6
5
PTA5
PTB6
PTB5
PTC6
PTC5
PTD6
PTD5
= Unimplemented
4
3
PTA4
PTA3
Unaffected by reset
PTB4
PTB3
Unaffected by reset
PTC4
PTC3
Unaffected by reset
PTD4
PTD3
Unaffected by reset
Figure 17-1. I/O Port Register Summary
2
PTA2
PTB2
PTC2
PTD2
1
PTA1
PTB1
PTC1
PTD1
Bit 0
PTA0
PTB0
PTC0
PTD0
MC68HC908GZ8
MOTOROLA
Input/Output (I/O) Ports
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Data Sheet
199