MC68HC708MP16 Datasheet, PDF (320/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
15.3 Port A
Port A is an 8-bit general-purpose bidirectional I/O port.
15.3.1 Port A Data Register
The port A data register (PTA) contains a data latch for each of the eight
port A pins.
Address: $0000
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Write:
Reset:
PTA7
PTA6
PTA5 PTA4 PTA3 PTA2
Unaffected by reset
PTA1
PTA0
Figure 15-2. Port A Data Register (PTA)
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.
15.3.2 Data Direction Register A
Data direction register A (DDRA) determines whether each port A pin is
an input or an output. Writing a logic 1 to a DDRA bit enables the output
buffer for the corresponding port A pin; a logic 0 disables the output
buffer.
Address: $0004
Bit 7
6
5
4
3
2
1
Read:
DDRA7
Write:
DDRA6
DDRA5
DDRA4
DDRA3
DDRA2
DDRA1
Reset: 0
0
0
0
0
0
0
Figure 15-3. Data Direction Register A (DDRA)
Bit 0
DDRA0
0
Technical Data
320
Input/Output (I/O) Ports
MC68HC708MP16 — Rev. 3.1
Freescale Semiconductor