
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
187 of 487
NXP Semiconductors
UM10800
Chapter 13: LPC82x USART0/1/2
•
Enable the USART interrupt in the NVIC.
•
Any USART interrupt wakes up the part from sleep mode. Enable the USART
interrupt in the INTENSET register (
).
13.3.2.2 Wake-up from Deep-sleep or Power-down mode
•
Configure the USART in synchronous slave mode. See
. You must connect
the SCLK function to a pin and connect the pin to the master.
•
Enable the USART wake-up in the STARTERP1 register. See
interrupt wake-up enable register (STARTERP1, address 0x4004 8214) bit
description”
.
•
Enable the USART interrupt in the NVIC.
•
In the PDAWAKE register, configure all peripherals that need to be running when the
part wakes up.
•
The USART wakes up the part from Deep-sleep or Power-down mode on all events
that cause an interrupt and are also enabled in the INTENSET register. Typical
wake-up events are:
–
A start bit has been received.
–
The RXDAT buffer has received a byte.
–
Data is ready to be transmitted in the TXDAT buffer and a serial clock from the
master has been received.
–
A change in the state of the CTS pin if the CTS function is connected and the
DELTACTS interrupt is enabled. This event wakes up the part without the
synchronous UART clock running.
Remark:
By enabling or disabling the interrupt in the INTENSET register (
),
you can customize when the wake-up occurs in the USART receive/transmit protocol.
13.4 Pin description
Table 174. USART pin description
Function
I/O
Type
Connect
to
Use register
Reference
Description
U0_TXD
O
external
to pin
any pin
PINASSIGN0
Transmitter output for USART0. Serial transmit data.
U0_RXD
I
external
to pin
any pin
PINASSIGN0
Receiver input for USART0.
U0_RTS
O
external
to pin
any pin
PINASSIGN0
Request To Send output for USART0. This signal
supports inter-processor communication through the
use of hardware flow control. This feature is active
when the USART RTS signal is configured to appear
on a device pin.