MC68HC08AZ16 Datasheet, PDF (324/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

I/O Ports
Port A
Port A
Port A is an 8-bit general-purpose bidirectional I/O port.
Port A Data
Register (PTA)
The port A data register contains a data latch for each of the eight port
A pins.
PTA
$0000
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
PTA7 PTA6 PTA5 PTA4 PTA3 PTA2
Unaffected by reset
Figure 1. Port A data register (PTA)
1
PTA1
Bit 0
PTA0
PTA[7:0] — Port A Data Bits
These read/write bits are software programmable. Data direction of
each port A pin is under the control of the corresponding bit in data
direction register A. Reset has no effect on port A data.
Data direction
register A (DDRA)
Data direction register A determines whether each port A pin is an input
or an output. Writing a logic one to a DDRA bit enables the output buffer
for the corresponding port A pin; a logic zero disables the output buffer.
DDRA
$0004
Bit 7
6
5
4
3
2
Read:
DDRA7
Write:
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
Reset: 0
0
0
0
0
0
Figure 2 Data direction register A (DDRA)
1
DDRA1
0
Bit 0
DDRA0
0
DDRA[7:0] — Data direction register A Bits
These read/write bits control port A data direction. Reset clears
DDRA[7:0], configuring all port A pins as inputs.
1 = Corresponding port A pin configured as output
0 = Corresponding port A pin configured as input
3-io
MOTOROLA
I/O Ports
MC68HC08AZ32
323