CHAPTER 4 PORT FUNCTIONS
4.2.2 Port 1
This is a 2-bit I/O port with an output latch. Port 1 can be specified in the input or output mode in 1-bit units by
using port mode register 1 (PM1). When using the P10 and P11 pins as input port pins, on-chip pull-up resistors can
be connected in 2-bit units by using pull-up resistor option register 0 (PU0).
This port is set in the input mode when the RESET signal is input.
Figure 4-4 shows a block diagram of port 1.
Figure 4-4. Block Diagram of P10 and P11
V
DD
WRPU0
PU01
P-ch
RD
WRPORT
Output latch
(P10, P11)
P10, P11
WRPM
PM10, PM11
PU0:
PM:
RD:
Pull-up resistor option register 0
Port mode register
Port 1 read signal
WR:
Port 1 write signal
82
User’s Manual U15075EJ1V0UM00
NEC [ NEC ]
