General description – Philips P89LPC903 User Manual
Page 14
Philips Semiconductors
User’s Manual - Preliminary -
P89LPC901/902/903
GENERAL DESCRIPTION
2003 Dec 8
14
PIN DESCRIPTIONS - P89LPC902
MNEMONIC PIN NO. TYPE NAME AND FUNCTION
P0.0 - P0.6 2,3,5,6,7
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 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.
0
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
CMPREFComparator 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.
P1.5
4
I
Port 1: Port 1 is a single-bit input-only port. I/O port without a pull-up.
This pin has a Schmitt trigger.
Port 1 also provides the special function described below.
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-System 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.