MC68HC705J2 Datasheet, PDF (22/82 Pages) Freescale Semiconductor, Inc – member of the low-cost

Freescale Semiconductor, Inc.
3.3 Port B
1
Port B is a 6-bit general-purpose bidirectional I/O port. The contents of DDRB
2
determine whether each pin is an input or an output. Figure 3-4 and Figure 3-5
show the port B data register and DDRB.
3
PORTB — Port B Data Register
$0001
4
Bit 7
6
5
4
3
2
1
Bit 0
0
0
PB5
PB4
PB3
PB2
PB1
PB0
RESET:
5
NOT CHANGED BY RESET
Figure 3-4. Port B Data Register
6
PB5–PB0 — Port B Data Bits
7
These read/write bits are software-programmable. Data direction of each bit is
under the control of the corresponding DDRA bit.
8
DDRB — Port B Data Direction Register
$0005
9
Bit 7
6
5
4
3
2
1
Bit 0
10
RESET:
DDRB7
0
DDRB6 DDRB5
0
0
DDRB4
0
DDRB3 DDRB2
0
0
DDRB1
0
DDRB0
0
Figure 3-5. Port B Data Direction Register
11
DDRB7–DDRB0 — Port B Data Direction Bits
12
These read/write bits control port B data direction.
13
1 = Corresponding port B pin configured as output
0 = Corresponding port B pin configured as input
14
15
16
17
18
19
20
PARALLEL I/O
3-4
Rev. 2
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