MC68HC708MP16 Datasheet, PDF (322/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
15.4 Port B
Port B is an 8-bit general-purpose bidirectional I/O port that shares its
pins with the analog-to-digital convertor module (ADC).
15.4.1 Port B Data Register
The port B data register (PTB) contains a data latch for each of the eight
port B pins.
Address: $0001
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PTB7
Write:
PTB6
PTB5
PTB4
PTB3
PTB2
PTB1
PTB0
Reset:
Unaffected by reset
Figure 15-5. Port B Data Register (PTB)
PTB[7:0] — Port B Data Bits
These read/write bits are software-programmable. Data direction of
each port B pin is under the control of the corresponding bit in data
direction register B. Reset has no effect on port B data.
15.4.2 Data Direction Register B
Data direction register B (DDRB) determines whether each port B pin is
an input or an output. Writing a logic 1 to a DDRB bit enables the output
buffer for the corresponding port B pin; a logic 0 disables the output
buffer.
Address: $0005
Bit 7
6
5
4
3
2
1
Read:
DDRB7
Write:
Reset: 0
DDRB6
0
DDRB5
0
DDRB4
0
DDRB3
0
DDRB2
0
DDRB1
0
Figure 15-6. Data Direction Register B (DDRB)
Bit 0
DDRB0
0
Technical Data
322
Input/Output (I/O) Ports
MC68HC708MP16 — Rev. 3.1
Freescale Semiconductor