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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.
I 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)
I 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.
Table 4.4-1 Port 2 pins
Port
Pin name
P20/SEG36
P21/SEG37
P22/SEG38
Port 2
P23/SEG39
P24/SEG40
P25/SEG41
See Section 1.7 "I/O Pins and Pin Functions" for a description of the circuit type.
82
Function
P20 N-ch open-drain I/O
P21 N-ch open-drain I/O
P22 N-ch open-drain I/O
P23 N-ch open-drain I/O
P24 N-ch open-drain I/O
P25 N-ch open-drain I/O
Shared peripheral
SEG36 LCD segment driver output
SEG37 LCD segment driver output
SEG38 LCD segment driver output
SEG39 LCD segment driver output
SEG40 LCD segment driver output
SEG41 LCD segment driver output
I/O type
Input
Output
Segment / N-ch
CMOS
open-drain
Circuit
type
D
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