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S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X I/O PORTS
9-1
9 I/O PORTS
OVERVIEW
The S3C8275X/C8278X/C8274X microcontroller has seven bit-programmable I/O ports, P0−P6. Port 0−port 5 are
8-bit ports, port 6 is 4-bit. This gives a total of 52 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 S3C8275X/C8278X/C8274X can be configured to input or output mode. P2−P6 are shared with LCD
signals.
Table 9-1 gives you a general overview of S3C8275X/C8278X/C8274X I/O port functions.
Table 9-1. S3C8275X/C8278X/C8274X Port Configuration Overview
Port Configuration Options
0 1-bit programmable I/O port.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P0.0−P0.2 can be used as input for external interrupts INT and P0.3-P0.7 can be
used as T1CLK, TAOUT, TBOUT, CLKOUT, and BUZ.
1 1-bit programmable I/O port.
Schmitt trigger input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P1.3−P1.7 can be used as input for external interrupts INT and P1.0−P1.2 can be
used as SCK, SO, and SI.
2 1-bit programmable I/O port.
Input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P2 can be used as outputs for LCD segment signals.
3 1-bit programmable I/O port.
Input or push-pull, open-drain output and software assignable pull-ups.
Alternatively P3 can be used as outputs for LCD segment signals.
4 1-bit programmable I/O port.
Input or push-pull 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 output and software assignable pull-ups.
Alternatively P5 can be used as outputs for LCD segment signals.
6 1-bit programmable I/O port.
Input or push-pull output and software assignable pull-ups.
Alternately P6.0−P6.3 can be used as outputs for LCD common signals.