
I/O Ports
Technical Data
MC68H(R)C908JL3 — Rev. 1.1
148
I/O Ports
Freescale Semiconductor
12.3 Port A
Port A is an 7-bit special function port that shares all seven of its pins
pin also has software configurable pull-up device if the corresponding
port pin is configured as input port. PTA0 to PTA5 has direct LED drive
capability.
Addr.
Register Name
Bit 7
654321
Bit 0
$0000
Port A Data Register
(PTA)
Read:
0
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
$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:
0
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
DDRA0
Write:
Reset:
00000000
$0005
Data Direction Register B
(DDRB)
Read:
DDRB7
DDRB6
DDRB5
DDRB4
DDRB3
DDRB2
DDRB1
DDRB0
Write:
Reset:
00000000
$0007
Data Direction Register D
(DDRD)
Read:
DDRD7
DDRD6
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
DDRD0
Write:
Reset:
00000000
$000A
Port D Control Register
(PDCR)
Read:
0000
SLOWD7 SLOWD6 PTDPU7 PTDPU6
Write:
Reset:
00000000
$000D
Port A Input Pull-up
Enable Register
(PTAPUE)
Read:
PTA6EN PTAPUE6 PTAPUE5 PTAPUE4 PTAPUE3 PTAPUE2 PTAPUE1 PTAPUE0
Write:
Reset:
00000000
Figure 12-1. I/O Port Register Summary