UM10147_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 28 April 2008
8 of 134
NXP Semiconductors
UM10147
P89LPC952/954 User manual
P2.2/MOSI
30
34
28
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
29
33
27
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
28
32
26
I/O
P2.4 —
Port 2 bit 4.
I/O
SS —
SPI Slave select.
P2.5/SPICLK
27
31
25
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
26
-
-
I/O
P2.6 —
Port 2 bit 6.
P2.7
5
-
-
I/O
P2.7 —
Port 2 bit 7.
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 5.1 “Port configurations”
.
All pins have Schmitt triggered inputs.
Port 3 also provides various special functions as described
below:
P3.0/XTAL2/
CLKOUT
7
12
6
I/O
P3.0 —
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
6
11
5
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.
P4.0 to P4.7
I/O
Port 4:
Port 4 is an 8-bit I/O port with a user-configurable
output type. During reset Port 4 latches are configured in the
input only mode with the internal pull-up disabled. The
operation of Port 4 pins as inputs and outputs depends upon
the port configuration selected. Each port pin is configured
independently. Refer to
Section 5.1 “Port configurations”
.
All pins have Schmitt triggered inputs.
Port 4 also provides various special functions as described
below:
Table 1.
Pin description
…continued
Symbol
Pin
Type Description
LQFP48
PLCC44
LQFP44