Single-Chip Microcontroller User Manual

User manual Rev. 01 — 1 December 2008 7 of 139

NXP Semiconductors

UM10310

P89LPC9321 User manual

[1] Input/output for P1.0 to P1.4, P1.6, P1.7. Input for P1.5.

P2.5/SPICLK 16 I/O P2.5 — Port 2 bit 5.

I/O SPICLK — SPI clock. When configured as master, this pin is output; when

configured as slave, this pin is input.

P2.6/OCA 27 I/O P2.6 — Port 2 bit 6.

O OCA — Output Compare A.

P2.7/ICA 28 I/O P2.7 — Port 2 bit 7.

I ICA — Input Capture A.

P3.0 to P3.1 I/O Port 3: Port 3 is a 2-bit I/O port with a user-configurable output type. During reset

Port 3 latches are configured in the input only mode with the internal pull-up

disabled. The operation of Port 3 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 3 also provides various special functions as described below:

P3.0/XTAL2/

CLKOUT

9I/OP3.0 — Port 3 bit 0.

O XTAL2 — Output from the oscillator amplifier (when a crystal oscillator option is

selected via the flash configuration.

O CLKOUT — CPU clock divided by 2 when enabled via SFR bit (ENCLK -TRIM.6).

It can be used if the CPU clock is the internal RC oscillator, watchdog oscillator or

external clock input, except when XTAL1/XTAL2 are used to generate clock

source for the RTC/system timer.

P3.1/XTAL1 8 I/O P3.1 — Port 3 bit 1.

I XTAL1 — Input to the oscillator circuit and internal clock generator circuits (when

selected via the flash configuration). It can be a port pin if internal RC oscillator or

watchdog oscillator is used as the CPU clock source, and if XTAL1/XTAL2 are not

used to generate the clock for the RTC/system timer.

7IGround: 0 V reference.

21 I Power supply: This is the power supply voltage for normal operation as well as

Idle and Power-down modes.

Table 1. Pin description …continued

Symbol Pin Type Description