Datasheet
LPC82x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 1 — 1 October 2014 71 of 81
NXP Semiconductors
LPC82x
32-bit ARM Cortex-M0+ microcontroller
Unused pins with GPIO function should be configured as outputs set to LOW with their
internal pull-up disabled. To configure a GPIO pin as output and drive it LOW, select the
GPIO function in the IOCON register, select output in the GPIO DIR register, and write a 0
to the GPIO PORT register for that pin. Disable the pull-up in the pin’s IOCON register.
In addition, it is recommended to configure all GPIO pins that are not bonded out on
smaller packages as outputs driven LOW with their internal pull-up disabled.
[1] I = Input, O = Output, IA = Inactive (no pull-up/pull-down enabled), F = floating, PU = Pull-Up.
14.5 Pin states in different power modes
[1] Default and programmed pin states are retained in sleep, deep-sleep, and power-down modes.
Table 29. Termination of unused pins
Pin Default
state
[1]
Recommended termination of unused pins
RESET
/PIO0_5 I; PU In an application that does not use the RESET pin or its GPIO function, the
termination of this pin depends on whether Deep power-down mode is used:
• Deep power-down used: Connect an external pull-up resistor and keep pin in
default state (input, pull-up enabled) during all other power modes.
• Deep power-down not used and no external pull-up connected: can be left
unconnected if internal pull-up is disabled and pin is driven LOW and
configured as output by software.
all PIOn_m (not
open-drain)
I; PU Can be left unconnected if driven LOW and configured as GPIO output with pull-up
disabled by software.
PIOn_m (I2C open-drain) IA Can be left unconnected if driven LOW and configured as GPIO output by software.
VREFP - Tie to VDD.
VREFN - Tie to VSS.
Table 30. Pin states in different power modes
Pin Active Sleep Deep-sleep/Power-
down
Deep power-down
PIOn_m pins (not
I2C)
As configured in the IOCON
[1]
. Default: internal pull-up
enabled.
Floating.
PIO0_4, PIO0_5
(open-drain
I2C-bus pins)
As configured in the IOCON
[1]
. Floating.
RESET
Reset function enabled. Default: input, internal pull-up
enabled.
Reset function disabled; floating; if the part
is in deep power-down mode, the RESET
pin needs an external pull-up to reduce
power consumption.
PIO0_16/
WAKEUP
As configured in the IOCON
[1]
. WAKEUP function inactive. Wake-up function enabled; can be disabled
by software.