mc68hc908kx8 Freescale Semiconductor, Inc, mc68hc908kx8 Datasheet - Page 105

• Manufacturer Part Number: mc68hc908kx8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 11
Input/Output (I/O) Ports (PORTS)
11.1 Introduction
Thirteen bidirectional input/output (I/O) pins form two parallel ports in the 16-pin plastic dual in-line
package (PDIP) and small outline integrated circuit (SOIC) package in the MC68HC908KX8 part. All I/O
pins are programmable as inputs or outputs. Port A has software selectable pullup resistors if the port is
used as a general-function input port.
See
Freescale Semiconductor
$000D
$0000
$0001
$0004
$0005
Addr.
Figure 11-1
Port A Input Pullup Enable
Data Direction Register A
Data Direction Register B
Register Name
Port A Data Register
Port B Data Register
Register (PTAPUE)
Connect any unused I/O pins to an appropriate logic level, either V
Although the I/O ports do not require termination for proper operation,
termination reduces excess current consumption and the possibility of
electrostatic damage.
See page 106.
See page 108.
See page 106.
See page 109.
See page 108.
for a summary of the I/O port registers.
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
(DDRA)
(DDRB)
(PTA)
(PTB)
Reset:
Reset:
Reset:
Reset:
Reset:
Read:
Read:
Read:
Read:
Read:
Write:
Write:
Write:
Write:
Write:
Figure 11-1. I/O Port Register Summary
DDRB7
PTB7
Bit 7
0
0
0
0
0
0
= Unimplemented
DDRB6
PTB6
6
0
0
0
0
0
0
NOTE
DDRB5
PTB5
5
0
0
0
0
0
0
PTAPUE4
DDRA4
DDRB4
Unaffected by reset
Unaffected by reset
PTA4
PTB4
4
0
0
0
PTAPUE3
DDRA3
DDRB3
PTA3
PTB3
3
0
0
0
PTAPUE2
DDRA2
DDRB2
DD
PTA2
PTB2
2
0
0
0
or V
SS
PTAPUE1
.
DDRA1
DDRB1
PTA1
PTB1
1
0
0
0
PTAPUE0
DDRA0
DDRB0
PTA0
PTB0
Bit 0
0
0
0
105