MC68HC705J2 Datasheet, PDF (21/82 Pages) Freescale Semiconductor, Inc – member of the low-cost

Freescale Semiconductor, Inc.
3.2 Port A
Port A is an 8-bit general-purpose bidirectional I/O port. The contents of DDRA
determine whether each pin is an input or an output. Figure 3-2 and Figure 3-3 show 1
the port A data register and DDRA.
2
PORTA — Port A Data Register
$0000
Bit 7
6
5
4
3
2
1
Bit 0
3
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
RESET:
NOT CHANGED BY RESET
4
Figure 3-2. Port A Data Register
5
PA7–PA0 — Port A Data Bits
6
These read/write bits are software-programmable. Data direction of each bit is
under the control of the corresponding DDRA bit.
7
DDRA — Port A Data Direction Register
$0004
8
Bit 7
6
5
4
3
2
1
Bit 0
0
0
DDRA5 DDRA4 DDRA3 DDRA2 DDRA1 DDRA0
9
RESET:
0
0
0
0
0
0
0
0
Figure 3-3. Port A Data Direction Register
10
DDRA7–DDRA0 — Port A Data Direction Bits
11
These read/write bits control port A data direction.
1 = Corresponding port A pin configured as output
12
0 = Corresponding port A pin configured as input
13
14
15
16
17
18
19
20
PARALLEL I/O
Rev. 2
3-3
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