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Table 1-3. Pin Functions (4)
Type
Dual-port DDB
7
RAM
Symbol
I/O
I/O
Name and function
Dual-port RAM Data Bus:
Bidirectional 8-bit bus by which
an external CPU can access the dual-port RAM.
Chip Select:
Input pin for selecting the dual-port RAM.
Register Select:
Input pins for addressing the dual-port RAM.
Output Enable:
Enables output on DDB
7
to DDB
0
.
Write Enable:
Enables writing to the dual-port RAM.
ReaDY:
For sending an interrupt request signal to an external
CPU. NMOS open-drain output.
Port 1:
An 8-bit input/output port with programmable MOS input
pull-ups and LED driving capability. The direction of each bit can
be selected in the port 1 data direction register (P1DDR).
Port 2:
An 8-bit input/output port with programmable MOS input
pull-ups and LED driving capability. The direction of each bit can
be selected in the port 2 data direction register (P2DDR).
Port 3:
An 8-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 3
data direction register (P3DDR).
Port 4:
An 8-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 4
data direction register (P4DDR).
Port 5:
A 3-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 5
data direction register (P5DDR).
Port 6:
An 8-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 6
data direction register (P6DDR).
Port 7:
An 8-bit input port.
Port 8:
A 7-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 8
data direction register (P8DDR).
Port 9:
An 8-bit input/output port with programmable MOS input
pull-ups. The direction of each bit can be selected in the port 9
data direction register (P9DDR).
to DDB
0
CS
RS
3
to RS
0
OE
WE
RDY
I
I
I
I
O
General-
purpose
I/O
P1
7
to P1
0
I/O
P2
7
to P2
0
I/O
P3
7
to P3
0
I/O
P4
7
to P4
0
I/O
P5
2
to P5
0
I/O
P6
7
to P6
0
I/O
P7
7
to P7
0
P8
6
to P8
0
I
I/O
P9
7
to P9
0
I/O
15