381
Programmable I/O Ports
M
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u
M
S
b
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3
M
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0
I
C
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2
R
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1
O
c
r
8
C
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c
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G
M
m
p
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P
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r
p
R
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U
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N
G
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-
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P
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6
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(5) I/O functions of built-in peripheral devices
Table 2.15.1 shows relation between ports and I/O functions of built-in peripheral devices.
Table 2.15.1. Relation between ports and I/O functions of built-in peripheral devices
Port
Internal peripheral device I/O pins
FLD controller output pins
FLD controller output pins
P4
0
to P4
3
FLD controller output pins/UART0 I/O pins
P4
4
to P4
7
FLD controller output pins
(6) Examples of working on non-used pins
Table 2.15.2 contains examples of working on non-used pins. There are shown here for mere ex-
amples. In practical use, make suitable changes and perform sufficient evaluation in compliance with
you application.
(a) Single-chip mode
Table 2.15.2. Examples of working on unused pins in single-chip mode
P0 to P3
P5, P6
P7
0
to P7
2
P7
3
P7
4
to P7
7
P8
0
to P8
5
P8
6
, P8
7
P9
0
to P9
5
P9
6
P9
7
Timer B0 to B2 input pins
Timer A0 I/O pin
Timer A1 to A4 input pins/UART1 I/O pins
External interrupt input pins
Sub-clock input pins
I/O pins of serial I/O with automatic transfer function
A-D converter input pins
D-A converter output pin/ X
IN
division clock output pin
/ DIM signal output pin of FLD controller
P10
0
to P10
7
D-A converter output pin/Clock I/O pin of serial I/O with automatic transfer function
Pin name
Connection
Ports P3, P4, P7 to P10
X
OUT
(Note 2), V
EE
After setting for input mode, connect every pin to V
SS
or V
CC
via a
resistor; or after setting for output mode, leave these pins open.
(Note 1)
Open
AV
SS
, V
REF
Connect to V
SS
If setting these pins in output mode and opening them, ports are in input mode until switched into
output mode by use of software after reset. Thus the voltage levels of the pins become unstable,
and there can be instances in which the power source current increases while the ports are in
input mode.
In view of an instance in which the contents of the direction registers change due to a runaway
generated by noise or other causes, setting the contents of the direction registers periodically by
use of software increases program reliability.
When an external clock is input to the X
IN
pin.
Note 1:
Note 2:
Ports P0 to P2, P5, P6
Open