MC908AB32CFUE Datasheet, PDF (316/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
17.3 Port A
Port A is an 8-bit general-purpose bidirectional I/O port.
17.3.1 Port A Data Register (PTA)
The port A data register 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:
PTA7
Write:
PTA6
PTA5
PTA4
PTA3
PTA2
PTA1
PTA0
Reset:
Unaffected by Reset
Figure 17-2. 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.
17.3.2 Data Direction Register A (DDRA)
Data direction register A 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 17-3. Data Direction Register A (DDRA)
Bit 0
DDRA0
0
Technical Data
316
Input/Output (I/O) Ports
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor