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CHAPTER 4 I/O PORTS
4.4 Port 2
Port 2 is N-ch open-drain I/O port that also serves as LCD segment driver outputs. Port
2 pins can be switched between LCD segment driver output and port operation by mask
option. This section principally describes the port functions when operating as N-ch
open-drain I/O port.
The section describes the port structure and pins, the pin block diagram, and the port
register for port 2.
■ Structure of port 2
Port 2 consists of the following two components:
• N-ch open-drain I/O pins/LCD segment driver output pins (P20/SEG36 to P25/SEG41)
• Port 2 data register (PDR2)
■ Port 2 pins
Port 2 consists of six N-ch open-drain I/O. When pins are used by the peripheral, they cannot be used as N-
ch open-drain I/O.
Table 4.4-1 "Port 2 pins" lists the port 2 pins.
See Section 1.7 "I/O Pins and Pin Functions" for a description of the circuit type.
Table 4.4-1 Port 2 pins
Port Pin name Function Shared peripheral
I/O type
Circuit
type
Input Output
Port 2
P20/SEG36 P20 N-ch open-drain I/O SEG36 LCD segment driver output
CMOS
Segment / N-ch
open-drain
D
P21/SEG37 P21 N-ch open-drain I/O SEG37 LCD segment driver output
P22/SEG38 P22 N-ch open-drain I/O SEG38 LCD segment driver output
P23/SEG39 P23 N-ch open-drain I/O SEG39 LCD segment driver output
P24/SEG40 P24 N-ch open-drain I/O SEG40 LCD segment driver output
P25/SEG41 P25 N-ch open-drain I/O SEG41 LCD segment driver output