MC68HC908JK1 Datasheet, PDF (153/210 Pages) Motorola, Inc – MC68HC908JK1

I/O Ports
Port B
12.5 Port B
Port B is an 8-bit special function port that shares all eight of its port pins
with the Analog-to-Digital converter (ADC) module, See Section 11.
12.5.1 Port B Data Register (PTB)
The port B data register contains a data latch for each of the eight port B
pins.
Address: $0001
Bit 7
6
5
4
3
2
Read:
PTB7
Write:
PTB6
PTB5
PTB4
PTB3
PTB2
Reset:
Unaffected by reset
Alternative Function: ADC7 ADC6 ADC5 ADC4 ADC3 ADC2
Figure 12-6. Port B Data Register (PTB)
1
PTB1
ADC2
Bit 0
PTB0
ADC0
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.
12.5.2 Data Direction Register B (DDRB)
Data direction register B determines whether each port B pin is an input
or an output. Writing a logic one to a DDRB bit enables the output buffer
for the corresponding port B pin; a logic zero disables the output buffer.
Address: $0005
Bit 7
6
5
4
3
2
1
Read:
DDRB7 DDRB6 DDRB5 DDRB4 DDRB3 DDRB2 DDRB1
Write:
Reset: 0
0
0
0
0
0
0
Figure 12-7. Data Direction Register B (DDRB)
Bit 0
DDRB0
0
MC68H(R)C908JL3 — Rev. 1.0
MOTOROLA
I/O Ports
Technical Data
153