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15. GENERAL-PURPOSE PORT
A general-purpose port outputs a high level, low level, or floating signal to an external circuit and reads
a high level or low level signal from an external circuit.
15.1 CONFIGURATION AND CLASSIFICATION OF GENERAL-PURPOSE PORT
Fig. 15-1 shows a block diagram of the general-purpose port.
Table 15-1 lists the classifications of general-purpose ports.
As shown in Fig. 15-1, the general-purpose port consists of Port0A (P0A) to Port1C (P1C), that set data
according to addresses 70H to 73H (port register) in each bank of data memory. The same port register is
mapped to both BANK0 and BANK2.
Each port consists of general-purpose port pins. For example, Port0A consists of pin P0A
As stated in Table 15-1, general-purpose ports are classified into I/O shared ports (I/O ports), input-only ports
(input ports), and output-only ports (output ports).
I/O ports are classified into bit I/O ports which allow I/O to be specified in 1-bit (1-pin) units and group
I/O ports in which I/O can be specified in 3-bit (3-pin) units .
0
1
2
3
0
1
2
Port register
3
4
5
6
7
Bit
Bit
I/O
I/O
Out In
P
P
P
P
0
0
0
0
A
B
C
D
P
P
P
P
0
0
0
0
A
A
A
A
3
2
1
pin
pin
pin
pin
Fig. 15-1 Block Diagram of General-Purpose Port
Column address
4
5
6
7
8
9
A
B
Data memory
BANK0
BANK1
Bit
Group
Bit
Bit
Out
I/O
I/O
I/O
I/O Out In
P
P
P
Fixed
P
P
at
1
1
1
0
0
0
A
B
C
A
B
I/O setting
Example configuration
of P0A pins
0
C
D
E
F
BANK2
System register
P
P
0
0
C
D
PD17062
to pin P0A
.
3
0
Control register
189
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