Philips Semiconductors
P89LPC901/902/903
8-bit microcontrollers with two-clock 80C51 core
Product data Rev. 05 — 17 December 2004 10 of 53
9397 750 14465
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
Table 4: P89LPC902 pin description
Symbol Pin Type Description
P0.0 to P0.6 I/O Port 0: Port 0 is an I/O port with a user-configurable output type. During reset Port 0
latches are configured in the input only mode with the internal pull-up disabled. The
operation of Port 0 pins as inputs and outputs depends upon the port configuration
selected. Each port pin is configured independently. Refer to Section 8.12.1 “Port
configurations” and Table 13 “DC electrical characteristics” for details.
The Keypad Interrupt feature operates with Port 0 pins.
All pins have Schmitt triggered inputs.
Port 0 also provides various special functions as described below:
3 I/O P0.0 — Port 0 bit 0.
I CMP2 — Comparator 2 output.
I KBI0 — Keyboard input 0.
2 I/O P0.2 — Port 0 bit 2.
I CIN2A — Comparator 2 positive input.
I KBI2 — Keyboard input 2.
7 I/O P0.4 — Port 0 bit 4.
I CIN1A — Comparator 1 positive input.
I KBI4 — Keyboard input 4.
6 I/O P0.5 — Port 0 bit 5.
I CMPREF — Comparator reference (negative) input.
I KBI5 — Keyboard input 5.
5 I/O P0.6 — Port 0 bit 6.
O CMP1 — Comparator 1 output.
I KBI6 — Keyboard input 6.
P1.0 to P1.5 Port 1: Port 1 is an I/O port with a user-configurable output type. During reset Port 1
latches are configured in the input only mode with the internal pull-up disabled. The
operation of the configurable Port 1 pins as inputs and outputs depends upon the
port configuration selected. Each of the configurable port pins are programmed
independently. Refer to Section 8.12.1 “Port configurations” and Table 13 “DC
electrical characteristics” for details. P1.5 is input only.
All pins have Schmitt triggered inputs.
Port 1 also provides various special functions as described below:
4IP1.5 — Port 1 bit 5 (input only).
I
RST — External Reset input during Power-on or if selected via UCFG1. When
functioning as a reset input a LOW on this pin resets the microcontroller, causing I/O
ports and peripherals to take on their default states, and the processor begins
execution at address 0. Also used during a power-on sequence to force In-System
Programming mode.
V
SS
8IGround: 0 V reference.
V
DD
1IPower Supply: This is the power supply voltage for normal operation as well as Idle
and Power-down modes.
