
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
184 of 487
13.1 How to read this chapter
Three USARTs are available on all parts depending on the switch matrix configuration.
13.2 Features
•
7, 8, or 9 data bits and 1 or 2 stop bits
•
Synchronous mode with master or slave operation. Includes data phase selection and
continuous clock option.
•
Multiprocessor/multidrop (9-bit) mode with software address compare.
•
RS-485 transceiver output enable.
•
Parity generation and checking: odd, even, or none.
•
Software selectable oversampling from 5 to 16 clocks in asynchronous mode.
•
One transmit and one receive data buffer.
•
RTS/CTS for hardware signaling for automatic flow control. Software flow control can
be performed using Delta CTS detect, Transmit Disable control, and any GPIO as an
RTS output.
•
Received data and status can optionally be read from a single register
•
Break generation and detection.
•
Receive data is 2 of 3 sample "voting". Status flag set when one sample differs.
•
Built-in Baud Rate Generator with autobaud function.
•
A fractional rate divider is shared among all USARTs.
•
Interrupts available for Receiver Ready, Transmitter Ready, Receiver Idle, change in
receiver break detect, Framing error, Parity error, Overrun, Underrun, Delta CTS
detect, and receiver sample noise detected.
•
Loopback mode for testing of data and flow control.
•
USARTn transmit and receive functions can operated with the system DMA
controller.
13.3 Basic configuration
Configure the USARTs for receiving and transmitting data:
•
In the SYSAHBCLKCTRL register, set bit 3 to 5 (
) to enable the clock to the
register interface.
•
Clear the USART peripheral resets using the PRESETCTRL register (
).
•
Enable or disable the USART interrupts in slots #3 to #5 in the NVIC. See
.
•
Configure the USART pin functions through the switch matrix.
•
Configure the USART clock and baud rate. See
•
Send and receive lines are connected to DMA request lines. See
.
UM10800
Chapter 13: LPC82x USART0/1/2
Rev. 1.2 — 5 October 2016
User manual