Samsung S3P80C5 User Manual page 212

S3P80C5/C80C5/C80C8
9
I/O PORTS
OVERVIEW
The S3P80C5/C80C5/C80C8 microcontroller has three bit-programmable I/O ports, P0–P2. Two ports, P0-P1,
are 8-bit ports and P2 is a 3-bit port. This gives a total of 19 I/O pins in the S3P80C5/C80C5/C80C8"s 24-pin
package. Each port is bit-programmable and 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.
For IR universal remote controller applications, ports 0, and1 are usually configured to the keyboard matrix and
port 2 is used to transmit the remote controller carrier signal or to indicate operating status by turning on a LED.
Table 9-1 gives you a general overview of S3P80C5/C80C5/C80C8 I/O port functions.
Port
0 8-bit general-purpose I/O port; Input or push-pull output; external interrupt input on falling
edges, rising edges, or both edges; all P0 pin circuits have noise filters and interrupt
enable/disable (P0INT) and pending control (P0PND); Pull-up resistors can be assigned to
individual P0 pins using P0PUR register settings. Specially Interrupt with Reset(INTR) is
assigned to release stop mode with system reset.
1 8-bit general-purpose I/O port; Input, open-drain output, or push-pull output. Pull-up resistors
can be assigned to individual P1 pins using P1PUR register settings.
2 3-bit I/O port; input mode with or without pull-up, push-pull or open-drain output mode. REM
and T0PWM can be assigned. Port 2 pins have high current drive capability to support LED
applications. The port 2 data register contains three status bits: three for P2.0, P2.1 and P2.2
and one for remote controller carrier signal on/off status.
Table 9-1. S3P80C5/C80C5/C80C8 Port Configuration Overview
Configuration Options
I/O PORTS
9-1