
1.6 Pin Description
10
Chapter 1: Overview
1.6 Pin Description
Table 1.6 Pin Description
Pin No.
Name
Circuit type
Function
1 to 8
P20/A00 to
P27/A07
F
P20 to P27 are not available for use as general-purpose ports.
A00 to A07 are the output pins for the lower 8 bits of the
external address bus.
9
VSS
power supply
Ground level pin for digital circuits
10 to
17
P30/A08 to
P37/A15
F
P30 to P37 are not available for use as general-purpose ports.
A08 to A15 are the output pins for the middle 8 bits of the
external address bus.
18
P40/A16
F
P40 is a general-purpose I/O port. This function is enabled
when the corresponding bit in the upper address control regis-
ter is set to 'port.'
A16 is the output pin for bit 16 of the external address bus.
This function is enabled when the corresponding bit in the
upper address control register is set to 'address.'
19
P41/A17
F
P41 is a general-purpose I/O port. This function is enabled
when the corresponding bit in the upper address control regis-
ter is set to 'port.'
A17 is the output pin for bit 17 of the external address bus.
This function is enabled when the corresponding bit in the
upper address control register is set to 'address.'
20
P42/A18/SID0
F
P42 is a general-purpose I/O port. This function is enabled
when the corresponding bit in the upper address control regis-
ter is set to 'port.'
A18 is the output pin for bit 18 of the external address bus.
This function is enabled when the corresponding bit in the
upper address control register is set to 'address.'
SID0 is the data input pin for UART #0. Because this function
is in continual use during UART #0 input operations, I/O
access from other functions should not be attempted unless
intended.
21
P43/A19/
SOD0
F
P43 is a general-purpose I/O port. This function is enabled
when UART #0 data output is disabled and the corresponding
bit in the upper address control register is set to 'port.'
A19 is the output pin for bit 19 of the external address bus.
This function is enabled when UART #0 data output is dis-
abled and the corresponding bit in the upper address control
register is set to 'address.'
SOD0 is the data output pin for UART #0. This function is
enabled when UART #0 data output is enabled.