Input/Output (I/O) Ports
Technical Data
MC68HC908AB32
—
Rev. 1.0
312
Input/Output (I/O) Ports
MOTOROLA
17.2 Introduction
Fifty-one bidirectional input-output (I/O) pins form eight parallel ports. All
I/O pins are programmable as inputs or outputs.
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
4
3
2
1
Bit 0
$0000
Port A Data Register
(PTA)
Read:
PTA7
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
PTA0
Write:
Reset:
Unaffected by reset
$0001
Port B Data Register
(PTB)
Read:
PTB7
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0
Write:
Reset:
Unaffected by reset
$0002
Port C Data Register
(PTC)
Read:
0
0
PTC5
PTC4
PTC3
PTC2
PTC1
PTC0
Write:
Reset:
Unaffected by reset
$0003
Port D Data Register
(PTD)
Read:
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0
Write:
Reset:
Unaffected by reset
$0004
Data Direction Register A
(DDRA)
Read:
DDRA7
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
Write:
Reset:
0
0
0
0
0
0
0
0
$0005
Data Direction Register B
(DDRB)
Read:
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
Write:
Reset:
0
0
0
0
0
0
0
0
$0006
Data Direction Register C
(DDRC)
Read:
MCLKEN
0
DDRC5
DDRC4
DDRC3
DDRC2
DDRC1
DDRC0
Write:
Reset:
0
0
0
0
0
0
0
0
$0007
Data Direction Register D
(DDRD)
Read:
DDRD7
DDRD6
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
DDRD0
Write:
Reset:
0
0
0
0
0
0
0
0
Figure 17-1. I/O Port Register Summary
Summary of Contents for MC68HC908AB32
Page 1: ...MC68HC908AB32 D REV 1 0 MC68HC908AB32 HCMOS Microcontroller Unit TECHNICAL DATA ...
Page 2: ......
Page 68: ...FLASH Memory Technical Data MC68HC908AB32 Rev 1 0 68 FLASH Memory MOTOROLA ...
Page 84: ...EEPROM Technical Data MC68HC908AB32 Rev 1 0 84 EEPROM MOTOROLA ...
Page 390: ...Ordering Information Technical Data MC68HC908AB32 Rev 1 0 390 Ordering Information MOTOROLA ...
Page 391: ......