General description – Philips P89LPC903 User Manual
Page 15
Philips Semiconductors
User’s Manual - Preliminary -
P89LPC901/902/903
GENERAL DESCRIPTION
2003 Dec 8
15
PIN DESCRIPTIONS - P89LPC903
MNEMONIC PIN NO. TYPE NAME AND FUNCTION
P0.0 - P0.6
2,6,7
I/O
Port 0: Port 0 is an I/O port with a user-configurable output types.
During reset Port 0 latches are configured in the input only
mode with the internal pullup 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 the section on I/O port
configuration and the DC Electrical Characteristics in the
Data Sheet 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.
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
CMPREFComparator reference (negative) input.
I
KBI5
Keyboard Input 5.
P1.0 - P1.5
3,4,5
Port 1: Port 1 is an I/O port with a user-configurable output types.
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 the section on I/O port configuration and the DC
Electrical Characteristics in the Data Sheet for details. P1.5
is input only.
All pins have Schmitt triggered inputs.
Port 1 also provides various special functions as described below.
5
I/O
P1.0
Port 1 bit 0.
O
TxD
Serial port transmitter data.
3
I/O
P1.1
Port 1 bit 1.
I
RxD
Serial port receiver data.
4
I
P1.5
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-Circuit Programming mode.
V
SS
8
I
Ground: 0V reference.
V
DD
1
I
Power Supply: This is the power supply voltage for normal operation as
well as Idle and Power down modes.