UM10310_1
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 01 — 1 December 2008
6 of 139
NXP Semiconductors
UM10310
P89LPC9321 User manual
P1.0/TXD
18
I/O
P1.0 —
Port 1 bit 0.
O
TXD —
Transmitter output for serial port.
P1.1/RXD
17
I/O
P1.1 —
Port 1 bit 1.
I
RXD —
Receiver input for serial port.
P1.2/T0/SCL
12
I/O
P1.2 —
Port 1 bit 2 (open-drain when used as output).
I/O
T0 —
Timer/counter 0 external count input or overflow output (open-drain when
used as output).
I/O
SCL —
I
2
C-bus serial clock input/output.
P1.3/INT0/SDA
11
I/O
P1.3 —
Port 1 bit 3 (open-drain when used as output).
I
INT0 —
External interrupt 0 input.
I/O
SDA —
I
2
C-bus serial data input/output.
P1.4/INT1
10
I/O
P1.4 —
Port 1 bit 4. High current source.
I
INT1 —
External interrupt 1 input.
P1.5/RST
6
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 ISP
mode.
P1.6/OCB
5
I/O
P1.6 —
Port 1 bit 6. High current source.
O
OCB —
Output Compare B
P1.7/OCC
4
I/O
P1.7 —
Port 1 bit 7. High current source.
O
OCC —
Output Compare C.
P2.0 to P2.7
I/O
Port 2:
Port 2 is an 8-bit I/O port with a user-configurable output type. During reset
Port 2 latches are configured in the input only mode with the internal pull-up
disabled. The operation of Port 2 pins as inputs and outputs depends upon the
port configuration selected. Each port pin is configured independently. Refer to
Section 4.1 “Port configurations”
for details.
All pins have Schmitt triggered inputs.
Port 2 also provides various special functions as described below:
P2.0/ICB
1
I/O
P2.0 —
Port 2 bit 0.
I
ICB —
Input Capture B.
P2.1/OCD
2
I/O
P2.1 —
Port 2 bit 1.
O
OCD —
Output Compare D.
P2.2/MOSI
13
I/O
P2.2 —
Port 2 bit 2.
I/O
MOSI —
SPI master out slave in. When configured as master, this pin is output;
when configured as slave, this pin is input.
P2.3/MISO
14
I/O
P2.3 —
Port 2 bit 3.
I/O
MISO —
When configured as master, this pin is input, when configured as slave,
this pin is output.
P2.4/SS
15
I/O
P2.4 —
Port 2 bit 4.
I/O
SS —
SPI Slave select.
Table 1.
Pin description
…continued
Symbol
Pin
Type
Description
