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S3C9228/P9228 I/O PORTS
9-1
9 I/O PORTS
OVERVIEW
The S3C9228/P9228 microcontroller has seven bit-programmable I/O ports, P0-P6. Port 0 is 6-bit port, port 1,
port 2, and port 6 are 4-bit ports, port 3 is 2-bit port, and port 4 and port 5 are 8-bit ports. This gives a total of 36
I/O pins. Each port can be flexibly configured to meet application design requirements.
The CPU accesses ports by directly writing or reading port registers. No special I/O instructions are required. All
ports of the S3C9228/P9228 except P0.4 and P0.5 can be configured to input or output mode. All LCD signal pins
are shared with normal I/O ports.
Table 9-1 gives you a general overview of S3C9228 I/O port functions.
Table 9-1. S3C9228 Port Configuration Overview
Port Configuration Options
0 1-bit programmable I/O port except P0.4 and P0.5.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
The P0.4 and P0.5 are only push-pull output ports.
Alternatively P0.0-P0.3 can be used as input for external interrupts INT and can be used as
TAOUT, T1CLK, and BUZ.
1 1-bit programmable I/O port.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P1 can be used as input for external interrupts INT and can be used as AD0-AD3.
2 1-bit programmable I/O port.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P2.0 and P2.1 can be used as outputs for LCD segment signals and P2.0-P2.2
can be used as SCK, SO, and SI.
3 1-bit programmable I/O port.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P3 can be used as input for external interrupts INTP and can be used as outputs
for LCD segment signals.
4 1-bit programmable I/O port.
Input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P4 can be used as outputs for LCD segment signals.
5 1-bit programmable I/O port.
Input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P5.0-P5.3 can be used as outputs for LCD segment signals and P5.4-P5.7 can be
used as outputs for LCD common or segment signals.
6 1-bit programmable I/O port.
Input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P6 can be used as outputs for LCD common signals.