
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 .
OTXD — Transmitter output for serial port.
P1.1/RXD 17 I/O P1.1 — Port1 bit 1.
IRXD — Receiver input for serial port.
P1.2/T0/SCL 12 I/O P1.2 — Port 1 bit2 (open-d rain when used as output).
I/O T0 — Timer/counter0 external count input or overflow output (open-drain when
used as output).
I/O SCL — I2C-bus serial clock input/output.
P1.3/INT0/SDA 11 I/O P1.3 — Port 1 bit 3 (open-drain when used as output).
IINT0 — External interrupt 0 input.
I/O SDA — I2C-bus serial data input/output.
P1.4/INT1 10 I/O P1.4 — Port 1 bit4. Hig h current source.
IINT1 — External interrupt 1 input.
P1.5/RST 6IP1.5 — Port 1 bit5 (input onl y).
IRST — 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 bit6 . High current source.
OOCB — Output Compare B
P1.7/OCC 4 I/O P1.7 — Port1 bit 7. High current source.
OOCC — Output Compare C.
P2.0 to P2.7 I/O Port2: Port 2 is an 8 -bit I/O port with a user-configurable output type. During reset
Port2 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.
Port2 also provides various special functions as described below:
P2.0/ICB 1 I/O P2.0 — Port 2 bit 0.
IICB — Input Capture B.
P2.1/OCD 2 I/O P2.1 — Port2 bit 1.
OOCD — Output Compare D.
P2.2/MOSI 13 I/O P2.2 — Port 2 bit2 .
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 bit3 .
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 — Port2 bit 4.
I/O SS — SPI Slave select.
Table 1. Pin description …continued
Symbol Pin Type Description