NEC switch - Functions of Ports

CHAPTER 4 PORT FUNCTIONS
User’s Manual U12978EJ3V0UD
58
Table 4-1. Functions of Ports
Pin Name I/O Function After Reset Alternate
Function
P00 to
P07
I/O Port 0
8-bit I/O port
Input/output can be specified in 1-bit units.
When used as an input port, use of on-chip pull-up resistors can be
specified by pull-up resistor option register 0 (PU0).
When used as an output port, CMOS output or N-ch open-drain
output can be specified in 8-bit units by port output mode register 0
(POM0).
Input —
P10 to
P17
I/O Port 1
8-bit I/O port
Input/output can be specified in 1-bit units.
When used as an input port, use of on-chip pull-up resistors can be
specified by pull-up resistor option register 0 (PU0).
When used as an output port, CMOS output or N-ch open-drain
output can be specified in 8-bit units by port output mode register 0
(POM0).
Input —
P20
SCK10
P21 SO10
P22 SI10
P23 —
P24 —
P25 —
P26
I/O Port 2
7-bit I/O port
Input/output can be specified in 1-bit units.
When used as an input port, use of on-chip pull-up resistors can be
specified by pull-up resistor option register 0 (PU0).
When P25 or P26 is used as an output port, CMOS output or N-ch
open-drain output can be specified in 1-bit units by port output mode
register 1 (POM1).
Input
INTP0/TI01/TO01
P40 to
P47
I/O Port 4
8-bit I/O port
Input/output can be specified in 1-bit units.
When used as an input port, use of on-chip pull-up resistors can be
specified by pull-up resistor option register 0 (PU0).
Input
KR00 to KR07